Title of Invention	RADIO-FREQUENCY SIGNAL RECEPTION AND/OR TRANSMISSION DEVICE WITH NOISE REDUCTION
Abstract	The radio-frequency signal reception and/or transmission device incluaes an antenna (8) for piciting up or transmitting radic-frequency signals, a bandpass fiiter (9), at least one low noise ampiifier (11; for ampilfying the filtered signals, an oscillator stage (1) for generating firs; high frequency signals (Svco), at least one frequency divider (14) for dividing by M the frequency of the first signals in order to generate second high frequency signals (So), where M is an integer number greater than 1, at least a first mixer unit (12) for mixing the filtered and amplified radio-frequency signals (SR) with the first high frequency signals (Svco), and at least a second mixer unit (13) for mixing the intermediate signals supplied by the first mixer unit with the second high frequency signals in order to produce baseband signals (IR, QR). The stage oscillator (1) is configured to generate first high frequency signals (Svco), whose frequency is outside the frequency band of the bandpass filter and higher than the frequency of the received radio-frequency signals by a factor M/N comprised between 1 and 2, where N is an integer number greater than 1. Figure 1

Title of Invention

RADIO-FREQUENCY SIGNAL RECEPTION AND/OR TRANSMISSION DEVICE WITH NOISE REDUCTION

Abstract

The radio-frequency signal reception and/or transmission device incluaes an antenna (8) for piciting up or transmitting radic-frequency signals, a bandpass fiiter (9), at least one low noise ampiifier (11; for ampilfying the filtered signals, an oscillator stage (1) for generating firs; high frequency signals (Svco), at least one frequency divider (14) for dividing by M the frequency of the first signals in order to generate second high frequency signals (So), where M is an integer number greater than 1, at least a first mixer unit (12) for mixing the filtered and amplified radio-frequency signals (SR) with the first high frequency signals (Svco), and at least a second mixer unit (13) for mixing the intermediate signals supplied by the first mixer unit with the second high frequency signals in order to produce baseband signals (IR, QR). The stage oscillator (1) is configured to generate first high frequency signals (Svco), whose frequency is outside the frequency band of the bandpass filter and higher than the frequency of the received radio-frequency signals by a factor M/N comprised between 1 and 2, where N is an integer number greater than 1. Figure 1

Full Text	RADIO-FREQUENCY SIGNAL RECEPTION AND/OF TRANSMISSION DEVICE WITH NOISE REDUCTION The invention concerns a low power radio-frequency signal reception and/or transmission device with noise reduction. A dual frequency conversion is carried out in the device so as to lower the frequency of the received radio-frrequency signals or to increase the frequency of baseband signals to be transmitted. In order to do this, the device includes a bandpass filter connected to a radio-frequency signal reception or transmission antenna, at least one low noise amplifier for amplifying the received or transmitted signals, and first and second mixer units for carrying out a dual frequency conversion using high frequency signals generated by an oscillator stage and a divider element. A dual frequency conversion for lowering the received radio-frequency signals to a baseband frequency is generally necessary. This avoids certain problems of disturbance in the case of a single frequency conversion when the radio-frequency signals are received or transmitted. US Patent Application No. 2005/0017887 discloses just such a radio-frequency signal reception and transmission device, able to perform a dual frequency conversion to lower the frequency of the received radio-frequency signals with a single antenna to a baseband frequency. A dual frequency conversion is also performed to generate radio-frequency signals to be transmitted by the same antenna on the basis of baseband signals. With a single frequency conversion, the high frequency signals generated by the oscillator stage and supplied to the mixer unit must have a substantially equal frequency to the frequency of the radio-frequency signals. Disturbance signals at harmonic frequencies to the frequency of the radio-frequency signals may be produced. Since the isolation of the mixer is limited, reverse disturbance radiation of the high frequency signals may occur in the direction of the antenna in the radio-frequency signal reception mode. This reverse radiation of equal frequencv to the radio-frequency signal frequency is tnus not fiitered by the input bandpass filter, Moreover. in transmission mode, the radio-frequency sinals produced at the equivalent frequency to the high frequency signals from the oscillator stage can influence the oscilator stage. Because or the radiation from the transmitted radio-frequency signals, a voltage controlled osciliaior of an oscillator stage is iiable to generate high frequency signals of higher frequency than the desired value. During frequency conversion in a radio-frequency signal reception/transmission device, a problem of noise has been observed, linked, on the one hand, to the amplifier and mixer unit, and on the other hand to the image frequency during frequency conversion. This image frequency is liable to disturb the useful data signals to be removed from the radio-frequency signals picked up, particularly dunng conversion from a high frequency to a low frequency. The image frequency signal gain at the output of the mixer unit is generally greater than the useful data signal gain, which may complicate the processing of the information contained in the radio-frequency signals picked up. Several embodiments of radio-frequency signal reception and/or transmission devices have already been proposed in the past for reducing part of the noise, in particular during frequency conversion of the radio-frequency signals picked up. In this regard, one could cite WO Patent Application No 03/009483 which discloses a device of this type for receiving and transmitting radio-frequency signals whose frequency may be equal to 2 GHz and 5 GHz using two filter antennas. Dunng the dual frequency conversion operations, a specific architecture is achieved for one of the mixer units so as to remove the image frequency of the converted signals. A voltage controlled oscillator is arranged for generating first high frequency signals whose frequency is comprised between 2 and 5 GHz such that after radio-frequency signals whose Trsquency is within the frequency band of the first filter or within the frequency band of the second filter. A first frequency conversion of the received anc filtered radio-frequency signals is performed by first mixer unit using first high frequency signals wnose frequency is Close to a mean vaiue between tne frequencies of tne signals filtered by the first or second Dandpass filters, in this manner, tne freauency of tne intermediate signals is a: a value close to 344 MHE. The solution proposed in JP Patent No 05-244032 also greatly complicates the structure of this communication device in particular by using several bandpass filters. This device provides no solution for reducing noise linked to the image frequency. The frequency vaiue of the first high frequency signals mixed with the received and filtered radio-frequency signals is chosen only so that the frequency of the intermediate signals at the output of the first mixer is always the same. Consequently no particular means are provided simply for reducing the noise linked to the image frequency. Moreover, a communication device of this type uses a great deal of electrical energy, and thus cannot be fitted to a small portable instrument powered by a battery or an electhcal energy accumulator. It is thus a main object of the invention to provide a low power radio-frequency signal reception and/or transmission device of simple design for easily reducing the noise mainly linked to the image frequency of the converted signals in order to overcome the aforecited drawbacks of the prior art. Moreover, as many as possible of the elements of the simply structured device must be able to be integrated in a single integrated circuit for the sake of saving space. The invention therefore concerns an aforecited low power radio-frequency signal reception and/or transmission device which is characterized in that the oscillator stage is configured so as to generate first high frequency signals, whose frequency is outside the frequency band of the bandpass filter and greater by a factor M/N comprised between 1 and 2 than the frequency of the received radio-frequency' signals., where N and M are integer numbers greater than with M. grearer. N butless than N One advantage of the recsption. and/or transmission device according to the invention lies in tne fact that, a large reduotion in the noise generated by an image frequency at the input of tne first mixer unit is ODiained, by generating first nigh frequency signals, whose frequency is greater than the frequency of tne received radio-frequency signais DV a determined factor. In this manner, the useful signais frequency. Moreover, s communication device of this type uses a great dea! of electricai energy, and thus cannot be fitred to a small portable instrument powered by a batterv or an electrical energy accumuiaton. It is thus a main object of tne invention to provide s low power radio-frequency signai reception and/or transmissior devics of simple design for easiiy reducind the noise mainiy linked to me image frequency of the converted signals in order to overcome the aforecited drawbacks of the prior art. iMoreover, as many as possible of the elements of the simpiy structured device must be able to be integrated in a single integrated circuit for the sake of saving space. The invention therefore concerns an aforecited low power radio-frequency signal reception and/or transmission device which is characterized in that the oscillator stage is configured so as to generate first high frequency signals, whose frequency is outside the frequency band of the bandpass filter and greater by a factor iVl/N compnsed between 1 and 2 than the frequency of the received radio-frequency signals, where N is an integer number greater than 1. One advantage of the reception and/or transmission device according to the invention lies in the fact that, a large reduction in the noise generated by an image frequency at the input of the first mixer unit is obtained, by generating first high frequency signals, whose frequency is greater than the frequency of the received radio-frequency signals by a determined factor. In this manner, the useful signals are less disturbed in order to facilitate subsequent demodulation operations. Preferably, the frequency of the first high frequency signals is greater than the frequency of the radio-frequency signals picked up by s factor of 4/3. After the first frequency conversion, the intermediate signals obtained thus have a frequency of a 1/3 the value of the frequency of the radio-frequency signals. This means that a second frequency conversion can easily be performed using second high frequency signals whose frequency is divided by 4 relative to the frequency of the first signals. Baseband signals, i.e. with a carrier frequency close to 0, are thus obtained after two frequency conversion operations using a simple structure and greatiy reducing the noise linked to the image frequency. Aavantageousiy, the structure of the reception and/or transmission device is achieved with a reduced number of components without any panicuiar shieid. Most of tne iovv power device can easity be integrated in a. single integrated circuit, for example made in G.25 um CMOS technology. Consequently, with the exception of the bandpass filter and a quartz crystal for the oscillator stage, all of the other elements are integrated in the integrated circuit. However, since the integrated low noise amplifier preceding the first mixer unit is one of the causes of the image frequency, it is thus advantageous for the oscillator stage to generate high frequency signals at a higher frequency than the radio-frequency signal frequency. The objects, advantages and features of the low power radio-frequency signal reception and/or transmission device will appear more cieariy in the following description of embodiments illustrated by the drawings, in which: - Figure 1 shows a first embodiment of a radio-frequency signal reception and/or transmission device according to the invention, - Figure 2 shows two graphs of the gain and noise of the amplified and converted signals at the output of the first mixer unit showing the level of disturbance signals at an image frequency as a function of the frequency of the first high frequency signals generated by the oscillator stage, - Figure 3 shows a second embodiment of a part of the device for transmitting radio-frequency signals according to the invention, and - Figure 4 shows a third embodiment of a part of the device for transmitting radio-frequency signals according to the invention. In the following description, the elements of the low power device for receiving and/or transmitting radio-frequency signals which are well known to those skilled in the art in this technical field are only related in a simplified manner. This device could be used in various appiications, such as in a cell telepnons in a telecommunications system for exampls or also for receiving: 3PS type signals for navigation operations. Figure 1 shows a radio-frsauency signal reception and/or transmission device according to tine invention in a simpiified manner illusirating, in particular, the input stage for frequency conversion ODerations on the signals tnat are picked up or transmitted, in order to do this, said device includes, first of a!!, an antenna 8 for receiving or transmitting radio-frequency RF signals, and a bandpass filter 9, which may be preceded by a low noise amplifier (not shown). This filter may be a selective SAW (surface acoustic wave) type bandpass filter. The bandpass filter is directly connected to a switch element 10 that can be controlled to place the device in a radio-frequency RF signal reception mode as shown in Figure 1, or in a radio-frequency signal ST transmission mode. For the reception of radio-frequency signals RF, the device also includes, after switch element 10, a low noise amplifier LHA 11 for amplifying the radio-frequency signals filtered by filter 9, and a first mixer unit 12 for performing a.first frequency conversion operation. The filtered and amplified signals SR are mixed in the first mixer unit with first high frequency signals Svco generated by an oscillator stage 1. The intermediate signals SINR thus produced by the first mixer unit 12 are mainly signals whose frequency is equal to the subtraction between the earner frequency of filtered radio-frequency signals SR and the frequency of the first high frequency signals Svco- Of course, according to the invention, in order to reduce the noise relating to the image frequency at the input of the first mixer unit 12 caused in part by amplifier 11, oscillator stage 1 is configured to generate first high frequency signals Svco whose frequency is determined to be greater than the carrierr frequency of the filtered and amplified radio-frequency signals SR by a factor of M/N. N and M are integer numbers where M is greater than N but less than 2N so that factor iVl/N is comprised between 1 and 2. The number M is preferably a multiple of 2, The frequency of the first high frequency signals must aisc be outside tns frequency range of input bandpass filter 3. This avoids navinc man frequency signal radiation tnrough the bandpass filter and the antenna in recection mode, since mixer unit 12 has limited isolation. According to a preferred embodiment of tne aevice, psciliator stage . is configured to generate first high frequency signals wnose frequency is substantially equal to 4/3 the frequency of filtered and amplified signals SR. In this way. for the second frequency conversion operation, it is possible to generate second high frequency in-phase and in-quadrature signals So on the basis of the first high frequency signals using a master-slave divide" 14 of simple design, for example a divider-by-4. Figure 2 illustrates well the advantage of generating first high frequency signals at a higher frequency than the frequency of the received radio-frequency signals in order to reduce tne influence of noise related to the image frequency at the input of the first mixer unit. According to the invention, the value of the image frequency at the input of the first mixer unit, which is partly caused by the low noise amplifier, is 5/3 the frequency fR of the radio-frequency signals when the frequency of the first high frequency signals is fixed at 4/3 of the frequency of the radio-frequency signals. However, the value of the image frequency at the output of the first mixer unit is 1/3 of the frequency fp, of the radio-frequency signals when the frequency of the first high frequency signals is conventionally fixed at 2/3 of the frequency of the radio-frequency signals. Consequently, it will be noted that according to the invention, the gain and noise level of the image frequency signals are much less than those of a conventional solution using first high frequency signals whose frequencv is lower than the frequency of the radio-frequency signals picked up. in the conventional solution, the detrimental noise relative to the image frequency is of the order of 4.5 dB, whereas according to the invention, this detnmental noise is only 1.5 dB. Thus, a large reduction of 3 dB is obtained in this detrimental noise reiative to tine useful signais ampiified by tns low noise ampiifier. This is a considerable advantage in s: low power cisvice for wnicn it is very imDonant to minimise noise raiativs to the useful signals. A decrease of even 0.5 dE in noise during recepiion of tne radio-frequency signals is already difficult to optain whatever tne architecture of the device. iVsoreover with a recuced numDe: of components, the Sow power device according to the invention can easiiy demodulate the data contained in the radio-'fequency signals picKed up This low power device can thus be fitted to an instrument of small size, such as a wristwatch or portable telephone. It should also be noted that selecting a frequency for the first high frequency signais that is higher than the radio-frequency signal frequency by a factor comprised between 1 and 2, prevents harmonic frequencies Deing generated duhng frequency conversion. With reference to Figure 1, oscillator stage 1 of the device includes mainly a frequency synthesiser with a voltage controlled oscillator VCO 6 for generating the first high frequency signals Svco- This oscillator stage 1 further includes a reference oscillator unit 3 with a quartz crystal 2, a phase and frequency detector 4 for comparing the frequency of the reference signals of oscillator 3 to the frequency of the signals from the voltage controlled oscillator VCO 6, which is divided by a factor n in divider 7. The control signals exiting detector 4 are filtered by a low pass filter 5 to produce a control voltage for the voltage controlled oscillator 6 as a function oi the comparison of the signals supplied to said detector 4. The frequency of the reference signals from oscillator 3 may be of the order of 8 MHz, whereas the frequency of the first nigh frequency signals may be of the order of 1.2 GHz. This high frequency only minimally increases the power consumption of the device compared to a conventional frequency of the order of 600 iVsHz. The device may be capable of picking UD radio-frequency signals with a carrier frequency close to 900 MHz depending upon the frequency range defined by bandpass filter 9. The device further includes a second mixer unit 13 for performing a second frequency conversion ooeration on intermediate signals SIMR. This secono mixer unit 13 is rormed of mixers not snovi/n; tor respeotively mixmg the second higr. frequenov signals resoeotiveiy -in-phase and in-quadrature with intermediete signals SINR. The signals producad by ine lwo mixers of the second mixer unir 13 are signals; whose frequency is equal to the subtraction between the freauency of Intermediate signals SIMR and the frequency of the second high frequency signals SD- AS in the preferred embodiment of the invention, the frequency of the second high frequency signals is substantially equal to the carrier frequency of the intermediate signals, the two output signals in-phase IR and in-quadrature QR are baseband signals with a earner frequency close to 0. Of course, a controlled gain amplifier could be provided at the output of second mixer unii 13, followed bv an anaiogue/digitai converter so as to supply sampled and quantified output signals IR and QR. In order to transmit radio-frequency signals, the device may also include a third mixer unit 15 for performing a first frequency conversion operation in order to increase the frequency of the baseband signals IT and QT. This third mixer unit 15 is formed of two mixers followed by an adder, as shown in Figure 3 deschbed below, for mixing the second high frequency in-phase and in-quadrature signals 3D respectively with the baseband signals IT and QT. Intermediate transmission signals SINT are supplied to the output of the adder of third mixer unit 15, whose frequency corresponds to the frequency of the second high frequency signals So- The frequency of these intermediate signals is preferably equal to 1/3 of the frequency of the radio-frequency signals to be transmitted ST. The device further includes a fourth mixer unit 16 for increasing the frequency of the intermediate transmission signals SINT Using first high frequency signals 3vco generated by osciiiator stage 1. The fourth mixer unit 16 supplies radio-frequency signals, which are amplified by a power ampiifier 17. The ampiified radio-frequency signals ST are transmitted by antenna 8 passinc through switch element 10 and r^andoass filte"" 9. Figure 6 shows a second embodiment of one. part of the devics for¬transmitting radio-frequency signals ST. Tnis second embodiment is substantiaily equivaient to that descnbed with reference tc Figure 1 for the device in transmission mode. in order tc iransmit radio-frequency signals, ine device includes s. third mixer unit 15 for performing a first frequency conversion operation. This first operation increases the frequency of the data signals IT and QT to be transmitted, which are in baseband, i.e. which have a carrier frequency close to 0. This third mixer unit 15 is formed of a first mixer 15a, a second mixer 15b and an adder 15c tor adding the signals exiting the first and second mixers. For this first frequency conversion operation, the frequency of the first high frequency signals Svco must be divided by 4 by a first divider-by-2 14a and a second master-siave aivider-by-2 i4b to supply second high frequency signals in-phase Si and in-quadrature SQ. The first mixer 15a mixes in-phase signals IT with the second high frequency in-phase signals S\|, whereas the second mixer 15b mixes in-quadrature signals QT with the second high frequency in-quadrature signals SQ. The signals exiting the first and second mixers 15a and 15b are added in adder 15c in order to supply intermediate transmission signals SINT at an equivalent frequency to the frequency of the second high frequency signals. A second frequency conversion operation is performed using a fourth mixer unit 16, which receives intermediate signals SINT and first high frequency signals Svco- The carrier frequency of the useful output radio-frequency signals from this fourth mixer unit Is 3/4 less than the frequency of the first high frequency signals according to the invention. The image frequency of the disturbance signals at the output of tnis fourth mixer unit whose value is 5/3 the frequency of the radio-frequency signals, may be easily filtered by a lowpass filter 18. Thus, the filtered signals can be amplified without any disturbance signals by the power amDiifier 17 in order to supply radio-freeuency signals ST that can be transmitted by the antenns. of tne device. without the lowpass filter, the disturbance signals wouio be ampiifieG in tne same way as the useful signals which would waste energy in amplifier 17. Figure - snows a third embodiment of one Dan: of tne device for transmitting radic-freauency signals ST. In order to transmit radio-frequency signals, the device includes a third mixer unit 15 for performing a first frequency conversion operation. This first operation increases the frequency of the data signals k and QT to be transmitted, which are baseband, i.e. which have a carrier frequency close to 0. This third mixer unit 15 is formed of a first mixer 15a and a second mixer 15b. For this first frequency conversion operation, the frequency of the first high frequency signals Svco must be divided by 4 as for the second embodiment, in oraer to do this the division is performed by a first master-slave divider-by-2 14a, which supplies third high frequency signals in-phase Si and in-quadrature SQ, followed by a second master-slave divider-by-2 14b receiving the divided in-phase signals from the first divider-by-2. The second divider-by-2 14b thus supplies second high frequency signals in-phase S\|, and in-quadrature SQ. The first mixer 15a mixes in-phase signals IT with the second high frequency in-phase signals S\| to supply first in-phase intermediate transmission signals SINTI. The second mixer 15b mixes in-quadrature signals QT with the second high frequency in-quadrature signals SQ to supply second intermediate transmission in-quadrature signals SNT2- The frequency of the first and second iniermediate signals is thus equivalent to the frequency of the second high frequency signals. .A second frequency conversion operation is performed using a fourtn mixer unit 19. This fourth mixer unit includes a first mixer 19a, a second mixer 19b and an adder 19c for adding the signals supplied by the first and second mixers. The first mixer 19a mixes intermediate in-phase signals SiNT1 with third high frequency in-phase slgnals S\\ whereas the second mixer 19b mixes- intermediaie ni-quaaraiure signals SINT2 with the third nigh frequency :n-quadraiur6 signsls, Sc- The ssgnais exiting tne fourth mber unit are radio-freauency signals which are finaliy amplified by the cower ampiifier 17 so thai the amplifiec radio-frequency signass ST can DS transmitted by the antenna of the device. It should be noted that with this third embodiment of one part of the device for transmitting radio-frequency signals, it is possible to perform an SSB (singie side band modulation) type dual conversion modulation. This structure omits the filter for the image frequency before the power amplifier, given that in this case, there is not image frequency to be filtered at the output of the fourth mixer unit 19. It is also advantageous to supply first high frequency signals Svco whose frequency has to be divided by the first and second dividers 14a and 14b to perform the two frequency conversions precisely. It would however be difficult to provide an oscillator that directly supplies the third high frequency in-phase and in-quadrature signals for mixing in the fourth mixer unit 19. From the description that has just been given, multiple variants of the low power device for receiving and/or transmitting radio-frequency signals with noise reduction can be devised by those skilled in the art without departing from the scope of the invention defined by the claims. The centra! frequency of the radio-frequency signals to be picked up could be detected so as to calibrate the oscillator stage for generating the first high frequency signals. The assembly formed by the amplifier and the two mixer units could be used both for the reception and transmission of the radio-frequency signals. CLAIM : 1. Radio-frequency signal reception and/or -transmission device, said low power device including: -a bandpass fiiter (9) to: fiitering the radio-frequency signals picked up or transmitted by an antenna (8) of the device -at least one iow noise ampiifier (11) for ampiifying tne signals filtered by the bandpass filter, -an oscillator stage (1) for generating first high frequency signals (Svco), - at least one frequency divider (14) for dividing the frequency of the first signals by M in order to generate second high frequency signals (So), where M is an integer number greater than 1, - at least a first mixer unit (12) for mixing the filtered and amplified radio-frequency signals (SR) with the first high frequency signals (Svco) in order to produce intermediate signals (SINR) whose frequency is equal to the subtraction between a carrier frequency of the radio-frequency signals and the frequency of the first signals, - at least a second mixer unit (13) for mixing the intermediate signals supplied by the first mixer unit with the second high frequency signals in order to produce output signals (IR, QR) whose frequency is equal to the subtraction between the frequency of the intermediate signals and the frequency of the second high frequency signals, said device being characterized in that the oscillator stage (1) is configured so as to generate first high frequency signals (Svoo) whose frequency is outside the frequency band of the bandpass filter and higher, by a factor M/N comprised between 1 and 2, than the frequency of the received radio-frequency signals, where N is an integer number greater thar 1, where M is greater than N bat less than 2-N to reduce the noise linked to the image frequency of the converted signals.. 2. Device according to claim 1 CHaracterizec in the the frequency of the first hign frequency signals is nigher than the Frequency of tne received radio-frequency signals by a factor M/N, where M is a multible of 2, prefersbly equal tc 4, whereas N is preferabiy equal to 3 defining a factcr equal to 4/3, and in that: the frequency divider (14' is a divider-Dy-4. 3. Device according to any one of the preceding claims, characterized in that the frequency divider (14) is of the master-slave type for generating second high frequency in-phase (S\|) and in-quadrature (SQ) signals, and in that the second mixer unit (13) includes a first mixer for mixing the intermediate signals (SINTI) with the second high frequency in-phase signals to supply in-phase baseband cutout signals (IR), and a second mixer for mixing the intermediate signals (SINTI) with the second high frequency in-quadrature signals to supply in-quadrature baseband output signals (QR). 4. Device according to any one of the preceding claims, characterized in that the stage oscillator (1) includes a reference oscillator unit (3) with a quartz crystal (2), a phase and frequency detector (4) for comparing the frequency of the reference signals from the oscillator (3) with the frequency of the signals from a voltage controlled oscillator (6), which is divided by a factor n in an oscillator divider (7), a lowpass filter (5) for producing a control voltage for the voltage controlled oscillator (6) as a function of the comparison of the signals supplied to said detector (4) such that the voltage controlled oscillator generates the first high frequency sianais. 5. Device according to claim 4, characterized in that the oscillator stage is configured to generate first high frequency signals based on detection of the frequency of the radio-frequency signals picked up by the antenna (8) of the device. 6. Device according to any one of the preceding ciaims, charaoterized in that in includes a switch element 10 between the bandpass filter (9 and the sow noise ampiifier (11) allowing saic device to be placed in a radio-frequency reception mode or in a radio-frequency transmission mode by the same antenna (8), 7. Device according to anv one of the preceding claims, characterized in that, for the transmission of radio-frequency signals, it includes a third mixer unit (15), which includes a first mixer (15a) for mixing the in-phase baseband data signals (IT) with the second high frequency in-phase signals (S\|), a second mixer (15b) for mixing in-quadrature baseband data signals (QT) with the second high frequency in-quadrature signals (SQ), and an adder (15c) for adding the output signals from the first and second mixers (15a, 15b) in order to provide intermediate transmission signals (SINTI), and in that it includes a fourth mixer unit (16) for mixing the intermediate transmission signals (SINTI) with the first high frequency signals (Svco) in order to supply radio-frequency signals, which are filtered by a lowpass filter (18) and amplified by a second power amplifier (17) to be transmitted by the antenna of the device. 8. Device according to any one of claims 1 to 6, characterized in that, for the transmission of radio-frequency signals, it includes a third mixer unit (15) , which includes a first mixer (15a) for mixing in-phase baseband data signals (IT) with the second high frequency in-phase signals (S\|) to supply intermediate in-phase signals (SINTI), S second mixer (15b) for mixing in-quadrature baseband data signals (QT) with the second hign frequency in-quadrature signals (SQ), to supply intermediate in-quadrature signals (SINTI), in that the frequency divider includes a first master-slave divider-by-2 (14a) for the first nigh frequency signals so as to supply third high frequency in-phase signals (Sr) and in-quadrature (Sc) and a second master-slave divider-by-2 (14b) for supply the second high frequency in-phase and in-quadrature signals, and in that it includes a fourth mixer unit '19;. which includes a first mixer (19a; for mixing the intermediats in-phass signals (SINTI; with the third high frequency in-phase- signals (S ), a second mixer '19b) for mixing the intermediate in-quadrature signals (SINTI; with the third high frequency in-quadrature signals (SQ'): and an adde;- (19a: for adding tine output signals from the first and second mixers (19a, 19b; of tne fourth unit in order to supply radio-frequency signals to be amplified by a second power amplifier (17) without passing through a lowpass filter and transmitted via the antenna of the device.

Full Text

RADIO-FREQUENCY SIGNAL RECEPTION AND/OF TRANSMISSION DEVICE WITH NOISE REDUCTION
The invention concerns a low power radio-frequency signal reception and/or transmission device with noise reduction. A dual frequency conversion is carried out in the device so as to lower the frequency of the received radio-frrequency signals or to increase the frequency of baseband signals to be transmitted. In order to do this, the device includes a bandpass filter connected to a radio-frequency signal reception or transmission antenna, at least one low noise amplifier for amplifying the received or transmitted signals, and first and second mixer units for carrying out a dual frequency conversion using high frequency signals generated by an oscillator stage and a divider element.
A dual frequency conversion for lowering the received radio-frequency signals to a baseband frequency is generally necessary. This avoids certain problems of disturbance in the case of a single frequency conversion when the radio-frequency signals are received or transmitted.
US Patent Application No. 2005/0017887 discloses just such a radio-frequency signal reception and transmission device, able to perform a dual frequency conversion to lower the frequency of the received radio-frequency signals with a single antenna to a baseband frequency. A dual frequency conversion is also performed to generate radio-frequency signals to be transmitted by the same antenna on the basis of baseband signals.
With a single frequency conversion, the high frequency signals generated by the oscillator stage and supplied to the mixer unit must have a substantially equal frequency to the frequency of the radio-frequency signals. Disturbance signals at harmonic frequencies to the frequency of the radio-frequency signals may be produced. Since the isolation of the mixer is limited, reverse disturbance radiation of the high frequency signals may

occur in the direction of the antenna in the radio-frequency signal reception mode. This reverse radiation of equal frequencv to the radio-frequency signal frequency is tnus not fiitered by the input bandpass filter, Moreover. in transmission mode, the radio-frequency sinals produced at the equivalent frequency to the high frequency signals from the oscillator stage can influence the oscilator stage. Because or the radiation from the transmitted radio-frequency signals, a voltage controlled osciliaior of an oscillator stage is iiable to generate high frequency signals of higher frequency than the desired value.
During frequency conversion in a radio-frequency signal
reception/transmission device, a problem of noise has been observed, linked, on the one hand, to the amplifier and mixer unit, and on the other hand to the image frequency during frequency conversion. This image frequency is liable to disturb the useful data signals to be removed from the
radio-frequency signals picked up, particularly dunng conversion from a high frequency to a low frequency. The image frequency signal gain at the output of the mixer unit is generally greater than the useful data signal gain, which may complicate the processing of the information contained in the radio-frequency signals picked up.
Several embodiments of radio-frequency signal reception and/or
transmission devices have already been proposed in the past for reducing part of the noise, in particular during frequency conversion of the radio-frequency signals picked up. In this regard, one could cite WO Patent Application No 03/009483 which discloses a device of this type for receiving
and transmitting radio-frequency signals whose frequency may be equal to 2 GHz and 5 GHz using two filter antennas. Dunng the dual frequency conversion operations, a specific architecture is achieved for one of the mixer units so as to remove the image frequency of the converted signals. A voltage controlled oscillator is arranged for generating first high frequency
signals whose frequency is comprised between 2 and 5 GHz such that after

radio-frequency signals whose Trsquency is within the frequency band of the first filter or within the frequency band of the second filter. A first frequency conversion of the received anc filtered radio-frequency signals is performed by first mixer unit using first high frequency signals wnose frequency is Close to a mean vaiue between tne frequencies of tne signals filtered by the first or second Dandpass filters, in this manner, tne freauency of tne intermediate signals is a: a value close to 344 MHE.
The solution proposed in JP Patent No 05-244032 also greatly complicates the structure of this communication device in particular by using several bandpass filters. This device provides no solution for reducing noise linked to the image frequency. The frequency vaiue of the first high frequency signals mixed with the received and filtered radio-frequency signals is chosen only so that the frequency of the intermediate signals at the output of the first mixer is always the same. Consequently no particular means are provided simply for reducing the noise linked to the image frequency. Moreover, a communication device of this type uses a great deal of electrical energy, and thus cannot be fitted to a small portable instrument powered by a battery or an electhcal energy accumulator.
It is thus a main object of the invention to provide a low power radio-frequency signal reception and/or transmission device of simple design for easily reducing the noise mainly linked to the image frequency of the converted signals in order to overcome the aforecited drawbacks of the prior art. Moreover, as many as possible of the elements of the simply structured device must be able to be integrated in a single integrated circuit for the sake of saving space.
The invention therefore concerns an aforecited low power radio-frequency signal reception and/or transmission device which is characterized in that the oscillator stage is configured so as to generate first high frequency signals, whose frequency is outside the frequency band of the bandpass filter and greater by a factor M/N comprised between 1 and 2

than the frequency of the received radio-frequency' signals., where N and M are integer numbers greater than with M. grearer. N butless than N
One advantage of the recsption. and/or transmission device according to the invention lies in tne fact that, a large reduotion in the noise generated by an image frequency at the input of tne first mixer unit is ODiained, by generating first nigh frequency signals, whose frequency is greater than the frequency of tne received radio-frequency signais DV a determined factor. In this manner, the useful signais

frequency. Moreover, s communication device of this type uses a great dea!
of electricai energy, and thus cannot be fitred to a small portable instrument powered by a batterv or an electrical energy accumuiaton.
It is thus a main object of tne invention to provide s low power radio-frequency signai reception and/or transmissior devics of simple design for easiiy reducind the noise mainiy linked to me image frequency of the converted signals in order to overcome the aforecited drawbacks of the prior art. iMoreover, as many as possible of the elements of the simpiy structured device must be able to be integrated in a single integrated circuit for the sake of saving space.
The invention therefore concerns an aforecited low power radio-frequency signal reception and/or transmission device which is characterized in that the oscillator stage is configured so as to generate first high frequency signals, whose frequency is outside the frequency band of the bandpass filter and greater by a factor iVl/N compnsed between 1 and 2 than the frequency of the received radio-frequency signals, where N is an integer number greater than 1.
One advantage of the reception and/or transmission device according to the invention lies in the fact that, a large reduction in the noise generated by an image frequency at the input of the first mixer unit is obtained, by generating first high frequency signals, whose frequency is greater than the frequency of the received radio-frequency signals by a determined factor. In this manner, the useful signals are less disturbed in order to facilitate subsequent demodulation operations.
Preferably, the frequency of the first high frequency signals is greater than the frequency of the radio-frequency signals picked up by s factor of 4/3. After the first frequency conversion, the intermediate signals obtained thus have a frequency of a 1/3 the value of the frequency of the radio-frequency signals. This means that a second frequency conversion can easily be performed using second high frequency signals whose frequency is divided by 4 relative to the frequency of the first signals. Baseband

signals, i.e. with a carrier frequency close to 0, are thus obtained after two frequency conversion operations using a simple structure and greatiy reducing the noise linked to the image frequency.
Aavantageousiy, the structure of the reception and/or transmission device is achieved with a reduced number of components without any panicuiar shieid. Most of tne iovv power device can easity be integrated in a. single integrated circuit, for example made in G.25 um CMOS technology. Consequently, with the exception of the bandpass filter and a quartz crystal for the oscillator stage, all of the other elements are integrated in the integrated circuit. However, since the integrated low noise amplifier preceding the first mixer unit is one of the causes of the image frequency, it is thus advantageous for the oscillator stage to generate high frequency signals at a higher frequency than the radio-frequency signal frequency.
The objects, advantages and features of the low power radio-frequency signal reception and/or transmission device will appear more cieariy in the following description of embodiments illustrated by the drawings, in which:
- Figure 1 shows a first embodiment of a radio-frequency signal
reception and/or transmission device according to the invention,
- Figure 2 shows two graphs of the gain and noise of the amplified
and converted signals at the output of the first mixer unit showing the level of disturbance signals at an image frequency as a function of the frequency of the first high frequency signals generated by the oscillator stage,
- Figure 3 shows a second embodiment of a part of the device for
transmitting radio-frequency signals according to the invention, and
- Figure 4 shows a third embodiment of a part of the device for
transmitting radio-frequency signals according to the invention.
In the following description, the elements of the low power device for
receiving and/or transmitting radio-frequency signals which are well known
to those skilled in the art in this technical field are only related in a simplified

manner. This device could be used in various appiications, such as in a cell
telepnons in a telecommunications system for exampls or also for receiving: 3PS type signals for navigation operations.
Figure 1 shows a radio-frsauency signal reception and/or transmission device according to tine invention in a simpiified manner illusirating, in particular, the input stage for frequency conversion ODerations on the signals tnat are picked up or transmitted, in order to do this, said device includes, first of a!!, an antenna 8 for receiving or transmitting radio-frequency RF signals, and a bandpass filter 9, which may be preceded by a low noise amplifier (not shown). This filter may be a selective SAW (surface acoustic wave) type bandpass filter. The bandpass filter is directly connected to a switch element 10 that can be controlled to place the device in a radio-frequency RF signal reception mode as shown in Figure 1, or in a radio-frequency signal ST transmission mode.
For the reception of radio-frequency signals RF, the device also includes, after switch element 10, a low noise amplifier LHA 11 for amplifying the radio-frequency signals filtered by filter 9, and a first mixer unit 12 for performing a.first frequency conversion operation. The filtered and amplified signals SR are mixed in the first mixer unit with first high frequency signals Svco generated by an oscillator stage 1. The intermediate signals SINR thus produced by the first mixer unit 12 are mainly signals whose frequency is equal to the subtraction between the earner frequency of filtered radio-frequency signals SR and the frequency of the first high frequency signals Svco-
Of course, according to the invention, in order to reduce the noise relating to the image frequency at the input of the first mixer unit 12 caused in part by amplifier 11, oscillator stage 1 is configured to generate first high frequency signals Svco whose frequency is determined to be greater than the carrierr frequency of the filtered and amplified radio-frequency signals SR by a factor of M/N. N and M are integer numbers where M is greater than N but less than 2N so that factor iVl/N is comprised between 1 and 2. The

number M is preferably a multiple of 2, The frequency of the first high
frequency signals must aisc be outside tns frequency range of input bandpass filter 3. This avoids navinc man frequency signal radiation tnrough the bandpass filter and the antenna in recection mode, since mixer unit 12 has limited isolation.
According to a preferred embodiment of tne aevice, psciliator stage . is configured to generate first high frequency signals wnose frequency is substantially equal to 4/3 the frequency of filtered and amplified signals SR. In this way. for the second frequency conversion operation, it is possible to generate second high frequency in-phase and in-quadrature signals So on the basis of the first high frequency signals using a master-slave divide" 14 of simple design, for example a divider-by-4.
Figure 2 illustrates well the advantage of generating first high frequency signals at a higher frequency than the frequency of the received radio-frequency signals in order to reduce tne influence of noise related to the image frequency at the input of the first mixer unit. According to the invention, the value of the image frequency at the input of the first mixer unit, which is partly caused by the low noise amplifier, is 5/3 the frequency fR of the radio-frequency signals when the frequency of the first high frequency signals is fixed at 4/3 of the frequency of the radio-frequency signals. However, the value of the image frequency at the output of the first mixer unit is 1/3 of the frequency fp, of the radio-frequency signals when the frequency of the first high frequency signals is conventionally fixed at 2/3 of the frequency of the radio-frequency signals. Consequently, it will be noted that according to the invention, the gain and noise level of the image frequency signals are much less than those of a conventional solution using first high frequency signals whose frequencv is lower than the frequency of the radio-frequency signals picked up.
in the conventional solution, the detrimental noise relative to the image frequency is of the order of 4.5 dB, whereas according to the invention, this detnmental noise is only 1.5 dB. Thus, a large reduction of 3

dB is obtained in this detrimental noise reiative to tine useful signais
ampiified by tns low noise ampiifier. This is a considerable advantage in s: low power cisvice for wnicn it is very imDonant to minimise noise raiativs to the useful signals. A decrease of even 0.5 dE in noise during recepiion of tne radio-frequency signals is already difficult to optain whatever tne architecture of the device. iVsoreover with a recuced numDe: of components, the Sow power device according to the invention can easiiy demodulate the data contained in the radio-'fequency signals picKed up This low power device can thus be fitted to an instrument of small size, such as a wristwatch or portable telephone.
It should also be noted that selecting a frequency for the first high frequency signais that is higher than the radio-frequency signal frequency by a factor comprised between 1 and 2, prevents harmonic frequencies Deing generated duhng frequency conversion.
With reference to Figure 1, oscillator stage 1 of the device includes mainly a frequency synthesiser with a voltage controlled oscillator VCO 6 for generating the first high frequency signals Svco- This oscillator stage 1 further includes a reference oscillator unit 3 with a quartz crystal 2, a phase and frequency detector 4 for comparing the frequency of the reference signals of oscillator 3 to the frequency of the signals from the voltage controlled oscillator VCO 6, which is divided by a factor n in divider 7. The control signals exiting detector 4 are filtered by a low pass filter 5 to produce a control voltage for the voltage controlled oscillator 6 as a function oi the comparison of the signals supplied to said detector 4.
The frequency of the reference signals from oscillator 3 may be of the order of 8 MHz, whereas the frequency of the first nigh frequency signals may be of the order of 1.2 GHz. This high frequency only minimally increases the power consumption of the device compared to a conventional frequency of the order of 600 iVsHz. The device may be capable of picking UD radio-frequency signals with a carrier frequency close to 900 MHz depending upon the frequency range defined by bandpass filter 9.

The device further includes a second mixer unit 13 for performing a second frequency conversion ooeration on intermediate signals SIMR. This secono mixer unit 13 is rormed of mixers not snovi/n; tor respeotively mixmg the second higr. frequenov signals resoeotiveiy -in-phase and in-quadrature with intermediete signals SINR. The signals producad by ine lwo mixers of the second mixer unir 13 are signals; whose frequency is equal to the subtraction between the freauency of Intermediate signals SIMR and the frequency of the second high frequency signals SD- AS in the preferred embodiment of the invention, the frequency of the second high frequency signals is substantially equal to the carrier frequency of the intermediate signals, the two output signals in-phase IR and in-quadrature QR are baseband signals with a earner frequency close to 0.
Of course, a controlled gain amplifier could be provided at the output of second mixer unii 13, followed bv an anaiogue/digitai converter so as to supply sampled and quantified output signals IR and QR.
In order to transmit radio-frequency signals, the device may also include a third mixer unit 15 for performing a first frequency conversion operation in order to increase the frequency of the baseband signals IT and QT. This third mixer unit 15 is formed of two mixers followed by an adder, as shown in Figure 3 deschbed below, for mixing the second high frequency in-phase and in-quadrature signals 3D respectively with the baseband signals IT and QT. Intermediate transmission signals SINT are supplied to the output of the adder of third mixer unit 15, whose frequency corresponds to the frequency of the second high frequency signals So- The frequency of these intermediate signals is preferably equal to 1/3 of the frequency of the radio-frequency signals to be transmitted ST.
The device further includes a fourth mixer unit 16 for increasing the frequency of the intermediate transmission signals SINT Using first high frequency signals 3vco generated by osciiiator stage 1. The fourth mixer unit 16 supplies radio-frequency signals, which are amplified by a power

ampiifier 17. The ampiified radio-frequency signals ST are transmitted by
antenna 8 passinc through switch element 10 and r^andoass filte"" 9.
Figure 6 shows a second embodiment of one. part of the devics for¬transmitting radio-frequency signals ST. Tnis second embodiment is substantiaily equivaient to that descnbed with reference tc Figure 1 for the device in transmission mode.
in order tc iransmit radio-frequency signals, ine device includes s. third mixer unit 15 for performing a first frequency conversion operation. This first operation increases the frequency of the data signals IT and QT to be transmitted, which are in baseband, i.e. which have a carrier frequency close to 0. This third mixer unit 15 is formed of a first mixer 15a, a second mixer 15b and an adder 15c tor adding the signals exiting the first and second mixers.
For this first frequency conversion operation, the frequency of the first high frequency signals Svco must be divided by 4 by a first divider-by-2 14a and a second master-siave aivider-by-2 i4b to supply second high frequency signals in-phase Si and in-quadrature SQ. The first mixer 15a mixes in-phase signals IT with the second high frequency in-phase signals S|, whereas the second mixer 15b mixes in-quadrature signals QT with the second high frequency in-quadrature signals SQ. The signals exiting the first and second mixers 15a and 15b are added in adder 15c in order to supply intermediate transmission signals SINT at an equivalent frequency to the frequency of the second high frequency signals.
A second frequency conversion operation is performed using a fourth mixer unit 16, which receives intermediate signals SINT and first high frequency signals Svco- The carrier frequency of the useful output radio-frequency signals from this fourth mixer unit Is 3/4 less than the frequency of the first high frequency signals according to the invention. The image frequency of the disturbance signals at the output of tnis fourth mixer unit whose value is 5/3 the frequency of the radio-frequency signals, may be easily filtered by a lowpass filter 18. Thus, the filtered signals can be

amplified without any disturbance signals by the power amDiifier 17 in order
to supply radio-freeuency signals ST that can be transmitted by the antenns. of tne device. without the lowpass filter, the disturbance signals wouio be ampiifieG in tne same way as the useful signals which would waste energy in amplifier 17.
Figure - snows a third embodiment of one Dan: of tne device for transmitting radic-freauency signals ST.
In order to transmit radio-frequency signals, the device includes a third mixer unit 15 for performing a first frequency conversion operation. This first operation increases the frequency of the data signals k and QT to be transmitted, which are baseband, i.e. which have a carrier frequency close to 0. This third mixer unit 15 is formed of a first mixer 15a and a second mixer 15b.
For this first frequency conversion operation, the frequency of the first high frequency signals Svco must be divided by 4 as for the second embodiment, in oraer to do this the division is performed by a first master-slave divider-by-2 14a, which supplies third high frequency signals in-phase Si and in-quadrature SQ, followed by a second master-slave divider-by-2 14b receiving the divided in-phase signals from the first divider-by-2. The second divider-by-2 14b thus supplies second high frequency signals in-phase S|, and in-quadrature SQ. The first mixer 15a mixes in-phase signals IT with the second high frequency in-phase signals S| to supply first in-phase intermediate transmission signals SINTI. The second mixer 15b mixes in-quadrature signals QT with the second high frequency in-quadrature signals SQ to supply second intermediate transmission in-quadrature signals SNT2- The frequency of the first and second iniermediate signals is thus equivalent to the frequency of the second high frequency signals.
.A second frequency conversion operation is performed using a fourtn mixer unit 19. This fourth mixer unit includes a first mixer 19a, a second mixer 19b and an adder 19c for adding the signals supplied by the first and second mixers. The first mixer 19a mixes intermediate in-phase signals

SiNT1 with third high frequency in-phase slgnals S\\ whereas the second
mixer 19b mixes- intermediaie ni-quaaraiure signals SINT2 with the third nigh frequency :n-quadraiur6 signsls, Sc- The ssgnais exiting tne fourth mber unit are radio-freauency signals which are finaliy amplified by the cower ampiifier 17 so thai the amplifiec radio-frequency signass ST can DS transmitted by the antenna of the device.
It should be noted that with this third embodiment of one part of the device for transmitting radio-frequency signals, it is possible to perform an SSB (singie side band modulation) type dual conversion modulation. This structure omits the filter for the image frequency before the power amplifier, given that in this case, there is not image frequency to be filtered at the output of the fourth mixer unit 19. It is also advantageous to supply first high frequency signals Svco whose frequency has to be divided by the first and second dividers 14a and 14b to perform the two frequency conversions precisely. It would however be difficult to provide an oscillator that directly supplies the third high frequency in-phase and in-quadrature signals for mixing in the fourth mixer unit 19.
From the description that has just been given, multiple variants of the low power device for receiving and/or transmitting radio-frequency signals with noise reduction can be devised by those skilled in the art without departing from the scope of the invention defined by the claims. The centra! frequency of the radio-frequency signals to be picked up could be detected so as to calibrate the oscillator stage for generating the first high frequency signals. The assembly formed by the amplifier and the two mixer units could be used both for the reception and transmission of the radio-frequency signals.

CLAIM :
1. Radio-frequency signal reception and/or -transmission device, said low power device including:
-a bandpass fiiter (9) to: fiitering the radio-frequency signals picked up or transmitted by an antenna (8) of the device
-at least one iow noise ampiifier (11) for ampiifying tne signals filtered by the bandpass filter,
-an oscillator stage (1) for generating first high frequency signals
(Svco),
- at least one frequency divider (14) for dividing the frequency of the first signals by M in order to generate second high frequency signals (So), where M is an integer number greater than 1,
- at least a first mixer unit (12) for mixing the filtered and amplified radio-frequency signals (SR) with the first high frequency signals (Svco) in order to produce intermediate signals (SINR) whose frequency is equal to the subtraction between a carrier frequency of the radio-frequency signals and the frequency of the first signals,
- at least a second mixer unit (13) for mixing the intermediate signals supplied by the first mixer unit with the second high frequency signals in order to produce output signals (IR, QR) whose frequency is equal to the subtraction between the frequency of the intermediate signals and the frequency of the second high frequency signals,
said device being characterized in that the oscillator stage (1) is configured so as to generate first high frequency signals (Svoo) whose frequency is outside the frequency band of the bandpass filter and higher, by a factor M/N comprised between 1 and 2, than the frequency of the received radio-frequency signals, where N is an integer number greater

thar 1, where M is greater than N bat less than 2-N to reduce the noise linked to the image frequency of the converted signals..
2. Device according to claim 1 CHaracterizec in the the frequency of the first hign frequency signals is nigher than the Frequency of tne received radio-frequency signals by a factor M/N, where M is a multible of 2, prefersbly equal tc 4, whereas N is preferabiy equal to 3 defining a factcr equal to 4/3, and in that: the frequency divider (14' is a divider-Dy-4.
3. Device according to any one of the preceding claims, characterized in that the frequency divider (14) is of the master-slave type for generating second high frequency in-phase (S|) and in-quadrature (SQ) signals, and in that the second mixer unit (13) includes a first mixer for mixing the intermediate signals (SINTI) with the second high frequency in-phase signals to supply in-phase baseband cutout signals (IR), and a second mixer for mixing the intermediate signals (SINTI) with the second high frequency in-quadrature signals to supply in-quadrature baseband output signals (QR).
4. Device according to any one of the preceding claims, characterized in that the stage oscillator (1) includes a reference oscillator unit (3) with a quartz crystal (2), a phase and frequency detector (4) for comparing the frequency of the reference signals from the oscillator (3) with the frequency of the signals from a voltage controlled oscillator (6), which is divided by a factor n in an oscillator divider (7), a lowpass filter (5) for producing a control voltage for the voltage controlled oscillator (6) as a function of the comparison of the signals supplied to said detector (4) such that the voltage controlled oscillator generates the first high frequency sianais.
5. Device according to claim 4, characterized in that the oscillator stage is configured to generate first high frequency signals based on detection of the frequency of the radio-frequency signals picked up by the antenna (8) of the device.

6. Device according to any one of the preceding ciaims, charaoterized in that in includes a switch element 10 between the bandpass filter (9 and the sow noise ampiifier (11) allowing saic device to be placed in a radio-frequency reception mode or in a radio-frequency transmission mode by the same antenna (8),
7. Device according to anv one of the preceding claims, characterized in that, for the transmission of radio-frequency signals, it includes a third mixer unit (15), which includes a first mixer (15a) for mixing the in-phase baseband data signals (IT) with the second high frequency in-phase signals (S|), a second mixer (15b) for mixing in-quadrature baseband data signals (QT) with the second high frequency in-quadrature signals (SQ), and an adder (15c) for adding the output signals from the first and second mixers (15a, 15b) in order to provide intermediate transmission signals (SINTI), and in that it includes a fourth mixer unit (16) for mixing the intermediate transmission signals (SINTI) with the first high frequency signals (Svco) in order to supply radio-frequency signals, which are filtered by a lowpass filter (18) and amplified by a second power amplifier (17) to be transmitted by the antenna of the device.
8. Device according to any one of claims 1 to 6, characterized in that, for the transmission of radio-frequency signals, it includes a third mixer unit (15) , which includes a first mixer (15a) for mixing in-phase baseband data signals (IT) with the second high frequency in-phase signals (S|) to supply intermediate in-phase signals (SINTI), S second mixer (15b) for mixing in-quadrature baseband data signals (QT) with the second hign frequency in-quadrature signals (SQ), to supply intermediate in-quadrature signals (SINTI), in that the frequency divider includes a first master-slave divider-by-2 (14a) for the first nigh frequency signals so as to supply third high frequency in-phase signals (Sr) and in-quadrature (Sc) and a second master-slave divider-by-2 (14b) for supply the second high frequency in-phase and in-quadrature signals, and in that it includes a fourth mixer unit

'19;. which includes a first mixer (19a; for mixing the intermediats in-phass signals (SINTI; with the third high frequency in-phase- signals (S ), a second mixer '19b) for mixing the intermediate in-quadrature signals (SINTI; with the third high frequency in-quadrature signals (SQ'): and an adde;- (19a: for adding tine output signals from the first and second mixers (19a, 19b; of tne fourth unit in order to supply radio-frequency signals to be amplified by a second power amplifier (17) without passing through a lowpass filter and transmitted via the antenna of the device.

Documents:

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Patent Number

278357

Indian Patent Application Number

4734/CHENP/2008

PG Journal Number

53/2016

Publication Date

23-Dec-2016

Grant Date

21-Dec-2016

Date of Filing

08-Sep-2008

Name of Patentee

THE SWATCH GROUP RESEARCH AND DEVELOPMENT LTD.

Applicant Address

REU DES SORS 3, 2074 MARIN,

Inventors:

#	Inventor's Name	Inventor's Address
1	ZELLWEGER, EMIL,	WOGACKERSTRASSE 6, CH-4514 LOMMISWIL,
2	CASAGRANDE, ARNAUD,	RUE DU MONTILIER 21, 2523 LIGNIERES,

PCT International Classification Number

H04B1/28

PCT International Application Number

PCT/EP07/52241

PCT International Filing date

2007-03-09

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	06110899.9	2006-03-09	EUROPEAN UNION