CN1177238A - System for reducing interference to electronic devices caused by discontinuous transmission radio transmitters - Google Patents

Abstract

A method for reducing interference to electronic devices caused by discontinuous transmission from a radio transmitter is disclosed and a transmitter which carries out such a method. In order to reduce such interference the transmitter continues to emit radiation at the same power level as when transmitting information, when no information needs to be-transmitted. When no information needs to be transmitted, the transmitter switches frequencies to another carrier frequency from the communication frequency so that other transmitters can transmit on the communication frequency when the transmitter is not transmitting information.

Description

The system that minimizing is caused by discontinuous transmission radio transmitters to the electronic equipment interference

The present invention relates to use pulse or the interrupted wireless terminal that sends, wherein might these pulsings will cause electromagnetic interference electronic equipment.

Modern wireless communication systems often contains the transmission of digital information.These systems often send packets of information from pulse mode, and the startup that transmitter is such is idle then, and and then starts.The advantage of this pulse/interrupted transmitting system is that for example a terminal is in when not sending when a transmitter, and other terminal can use same carrier frequency to send, this with regard to permission be tuned to a single receiver of this carrier frequency go to receive several transmissions.

A this system is based on time division multiple access (TDMA), and wherein one group of remote terminal is shared in the same carrier frequency that sends in the different cycles time slot.An example of this system is illustrated among the standard I S-54 of telecommunications industry association, is commonly referred to as North America digital cellular radio.In IS-54, remote terminal, it is a cell phone, sends the information of the time slot of about 6.6ms of duration in each 20ms frame; 33% duty cycle had both been arranged on the frame rate of 50Hz.During the sending time slots of 6.6ms, power level residue comes down to constant, unless because modulation intelligence is less than the variation of about 3dB to the carrier wave.This modulation occurs in 24K symbol/s, and is high more a lot of than frame speed.During the 13.4mS of remaining 20ms frame, phone can not be sent out.

Use increases in the digital cellular telephone household which owns machines for production, and a general configuration is near the wireless terminal of household electrical appliance, for example television set.Sometimes amplifying demodulation occurs in and often causes in these electronic installations of unwanted interference.Typically, its transmission is as follows.Radio frequency (RF) emission is picked up by a circuit lead and is coupled to a diode or triode knot.This RF of this knot detection and peripheral circuits provide low pass or bandpass filtering (if normally voiced band of voicefrequency circuit is arranged).Because the modulation of information, this has removed the variation of radio frequency carrier frequency widely, and because carrier wave is opened and closed in pulse, has broken away from serious variation basically.If to peripheral circuits, what obtain has an O D. C. value to this base band interference waveform by cross-couplings, in the 20ms cycle, duty cycle 33% and peak-crest voltage or current level relate to the square wave of the RF power level of transmission.It should be noted that this demodulation process is very unscientific for the little variation of carrier frequency.This waveform can cause a large amount of injurious effects; For example, the square wave of 50Hz can be heard by the buzz as worry in voicefrequency circuit.Such interference can also be in occurring in hearing-aid device.

The wireless transmission that similar problem also appears at its terminal that is not tdma system is in the interrupted wireless system; For example, carry out the use of voice activity detection (vad) in the system.Can be random except pulse characteristic rather than the cycle, this problem is identical.

In order to reduce the influence of interference, the radio frequency of wireless terminal is sent continuously or approaching as much as possible (duty cycle is near 100%) continuously.Therefore the interference to electronic equipment that will provide a kind of minimizing to be caused by the discontinuous transmission radio terminal is provided, and don't can causes the effectively system of loss of this radio system capacity.

According to one embodiment of the present of invention, wireless terminal with the carrier wave of its distribution send data during the communication time slot of its distribution, when finishing it and send, it just changes to the carrier frequency of another appointment, can be called " empty energy carrier wave ", and continues emission with same power level.For example, in tdma system, this terminal will send on this sky energy carrier wave to during the time slot of that terminal communication unallocated.Typically, this emission is not used to communication; Energy is being that " empty (wasted) " is as ensureing a kind of method that is sent this emission during general untapped time slot by this terminal simply on this carrier frequency.Therefore, the significant change in the carrier radio frequency environment is reduced to the very short time interval, send as requiring temporarily to close radio frequency, and this carrier frequency is converted between empty energy carrier wave.This carrier frequency that is used for letter that just allows to distribute is used for communication by other wireless terminal during these time slots, as the example in common tdma system, and significantly reduce the discontinuous/pulse characteristic of transmission power level.

Should be noted that the present invention is not limited to tdma system and can also be applied to use other system that continues transmission, for example use the system of time division duplex (TDD) or use voice activity detection.

Therefore, the aspect of broad sense according to the present invention is even provide a kind of such terminal to send the transmitting set that information also can reduce the fluctuation level of the power level that is sent by this transmitter intermittently.Like this, send interrupted information according to interrupted transmission transmitter according to the present invention, and with do not have information to be sent out transmitter that the time broken hair send to compare and kept relative constant transmission level.

Preferably, all wireless terminals in this wireless system use same empty energy carrier wave, and no matter these carrier frequency go distribute to them to communication.In this mode, have only a carrier frequency to become and in whole system, can not be used for communication, if many communication carrier frequency are arranged in this system, then it has the insignificant influence of pair power system capacity.

The aspect of broad sense according to the present invention is provided in the radio telecommunications system that uses interrupted transmission information, a kind of method that causes the interference that in electronic equipment, produces by transmitter that reduces, and the method comprising the steps of a) determines when information will be sent out; B) when information will be sent out tuning this transmitter to a carrier frequency that is used to communicate by letter; And c) tuning described transmitter arrives another carrier frequency when information is not transmitted.

Root another aspect of the present invention provides a kind of transmitter of interrupted transmission, comprises that a carrier-fequency generator is used for producing first carrier frequency that is sent out and is used for producing second carrier frequency that is sent out when information is not transmitted when information will be sent out; And a controller, be used for when information is sent out, driving described carrier-fequency generator and produce described first carrier frequency and when information is not sent out, produce described second carrier frequency.

Further aim of the present invention and advantage will be more clear from the explanation below with reference to the embodiment of accompanying drawing, wherein:

Fig. 1 a is the example that the radio frequency of the conventional IS-54 terminal of expression sends.

Fig. 1 b is illustrated in to amplify the interference waveform of seeing that obtains after the radio frequency waveform of separating mediation filtering Fig. 1 a in being subjected to jamming equipment.

Fig. 2 a is the example of expression according to the radio frequency transmission of the improved IS-54 terminal of the embodiment of the invention.

Fig. 2 b is illustrated in to amplify the interference waveform that obtains seeing after the radio frequency waveform of separating mediation filtering Fig. 2 a in being subjected to jamming equipment.

Fig. 3 represents the frequency scheme of typical digital cellular wireless system.

Fig. 4 is the block diagram of expression according to the terminal radio frequency circuit of one embodiment of the present of invention.

Fig. 5 is the further detailed block diagram of presentation graphs 4 terminals.

Fig. 6 is that the radio frequency of the conventional IS-95 terminal of expression sends.

Fig. 7 is the radio frequency transmission of expression according to embodiment of the invention IS-95 terminal.

Fig. 8 is the radio frequency transmission of expression according to embodiment of the invention Frequency Hopping Multiple Access FHMA.

In Fig. 1, show conventional IS-54 digital cellular terminal and send.Emission takes place with 20ms gap periods ground, shown in 100.Be separated with three communication time slots at each.During the time slot 101 that is assigned as its communication, the terminal of inquiry sends the information by the fc105 modulated carriers of allocate communications.In this 6.66ms time slot, launch frequently that the mean value of power level is P106, and owing to be modulated at several decibels very little change of existence in the power 107.These signaling rates that change with 24 kilo-characters/S occur.During two other time slot 102 and 103, this terminal does not send so that this carrier frequency fc can be used by two that close on other this terminals.

Fig. 1 b represents to cause an example of the interference waveform that produced by unwanted amplification demodulation, and it occurs in the equipment that is disturbed that is subjected to Fig. 1 a radiation.In this example, the radiation of Fig. 1 a, we will be referred to as the radio-frequency radiation ripple; Be detected, it causes envelope detection.This typically occurs in and tied by triode or diode semiconductor detection.The interference waveform of this generation is higher than 50Hz in fact with cut-off frequency and is lower than 24000Hz and is low pass filtering.This is because circuit capacitance and the parasitic capacitance in the transistor.It makes the high fdrequency component of carrier frequency and modulation rate be moved.At last, generation disturbing wave and the actual 50Hz of being lower than of cut-off frequency carry out AC coupled, it causes the skew of DC component, and does not significantly destroy square waveform.This occurs in the capacitive coupling circuit.This detection, filtering and AC coupled often occur in the many electronic circuits that contain in the household electrical appliance, particularly at hearing-aid device, in the audio amplifier circuit that may exist in broadcast band receiver and the television set.

The interference waveform 110 that produces is the square waves of following original radio frequency radiation envelope.Period T 22 is 20ms, and the cycle portions of positive waveform 144 is 6.66mS.We can define the mark of this duty cycle d for the cycle of the positive interference waveform of generation.In this case, d=33%.Peak one peak A 116 of the interference waveform 110 that produces is functions of power P in the radio frequency interference waveform during time slot 101.The interference waveform that it should be noted that generation is a relative insensitivity for for example distinguishing the change of switching the original carrier frequency that produces by mistake.

When the TDMA of IS-54 terminal radiation is used in this example, those of ordinary skill in the art will understand the emission of other type TDMA wireless terminal, for example corresponding to the European Digital Cellular System that is referred to as GSM with the different cycles, duty cycle and amplitude and produce same effect.

The average power of the interference waveform that produces is the ability measurement for the unwanted influence that produces, for example the audible noise in audio frequency apparatus.For square wave, this power can easily be calculated and and A ²D (1-d) is directly proportional.In this example, this power and 0.22A ²Be directly proportional.For constant amplitude A, when d=0.5 (square wave) this power maximum and when d is about 0 or 100% near 0.Therefore, if d energy quilt causes then that near 100% the interference performance that does not need to influence just can be reduced substantially.

In Fig. 2 a, show the radiation of the improved IS-54 digital cellular terminal of system of the present invention use.Radiation produces periodically with the interval 200 of 20mS.The terminal of inquiry sends information by modulation communication carrier frequency fc205 during the time slot 201 of distributing to its communication.During the time slot of this about 6.66mS, average radio frequency power level is P206, with identical in the modulation.These change with speed 24 kilo-characters of posting a letter/S generation.Different with Fig. 1 a, in other two time slots 202 and 203, this terminal also sends with power level P, but has been transformed into the frequency of being appointed as " empty energy carrier wave " fw208.

This terminal can be during time slot 202 and 203 with at random, pseudorandom, or the bit mode modulated carrier fw that is provided with.Therefore, substitute as a kind of, if owing to lack that to be modulated at the interference volume that produces in the different equipment of this generation power level relatively less, then this carrier wave can be with the fw emission of not modulating.Stopping between radiation era of reality, exist each only two very short time cycle e1 210 and e2211 of part millisecond, and transmitter is changed between fc and fw, to avoid in this system radiated interference on other communication carrier frequency.In addition, do not cause this wireless system receiver is disturbed and do not receive the chance of information, then at e1 with to break away from radio frequency power level during the e2 cycle be that P is possible if during these time cycles, do not exist.

Fig. 2 b is illustrated in the interference waveform 220 of the generation that can cause in the equipment that is subjected to Fig. 2 a radiated interference.The interference waveform 220 that produces is the square waves of following original radio frequency radiation envelope.Period T 222 is 20mS, and with the same among Fig. 1 b, but duty cycle d approaches 100%.Specifically, d=1-((e1+e2)/T).If e1=e2=0.2mS, then d=98%.The amplitude demodulation processing is not very responsive for becoming fw for carrier frequency from fc in a few percent only in carrier frequency varies.Peak-peak-to-peak amplitude the A226 of the interference waveform 220 that produces during time slot 201-203 is functions of radio-frequency radiation wave power P, and is identical with Fig. 1 b.Because duty cycle is 98% now, so the power of the interference waveform that produces is proportional to only about 9% 0.0196A of the so much power of situation that resembles Fig. 1 b now ²

Although the waveform in the example has been supposed perfect rectangle and carried out computational short cut, should know that even the baseband waveform that filtering produces is not a rectangle, the generation of interference also essence has reduced.

Fig. 3 represents to be used to utilize the example of system frequency scheme of the TDMA wireless system of one aspect of the invention.Frequency scheme in this example is based on the frequency spectrum of north American cellular allocation of communications.In any given authority, exist two cellular wireless systems that are referred to as A and B, handle by different service suppliers.In this scheme, 416 occupy 3.0KHz carrier frequency 310 at interval can be used for service supplier A distribute to these wireless terminals go to be used for by the base station of service supplier A manipulation or communicating by letter of mesh station.The carrier frequency fc among Fig. 2 of relating to for specific call can be in these carrier frequency any one.Single carrier frequency 824.01Mhz in addition is designated as the empty energy carrier wave 312 of service supplier A system.When they were not communicated by letter with the mesh station, these wireless terminals were in the emission of transferring to during these time slots on this carrier frequency.This carrier frequency is used by all wireless terminals among the A of system, and no matter a given terminal is used simultaneously for communication from this group particular frequency carrier 310.

Same, with 416 carrier frequency 320 of 30KHz arranged spaced can be used for service supplier B distribute to these wireless terminals go to be used for by the base station of service supplier B manipulation or communicating by letter of mesh station.It should be noted that in this example that for this purpose it is identical with the frequency that the A of system uses.Owing on empty energy carrier wave, do not have useful communication to take place, so a single carrier frequency just can be shared by these service suppliers, to reduce the number of carriers that communication can not utilize.Passive antenna by the circuit trace on typical circuit board forms for example may often have broadband response.In this example, carrier frequency is 3% from the communication carrier frequency to the worst case that empty energy carrier frequency changes, and this is subjected to have in the jamming equipment at majority handles insignificant the influence to amplitude demodulation.

Those of ordinary skill in the art knows that empty energy carrier wave can replace selecteed another carrier frequency, and need not distribute of sideband edge for communication equipment.In addition, in practice, have more than one frequency for each system and be designated as the sky energy channels.This may have minimizing and appear at the gross power of the many wireless terminals that occur on any particular frequency carrier of described as can be seen fixedly mesh station receiver, and can reduce the practical problem as intermodulation in the receiver of mesh station.Various empty energy carrier frequency can be preprogrammed into these wireless terminals, and perhaps they can distribute by the use information that is sent to these wireless terminals by base station or mesh station.

In this specific example, the frequency 312 that is chosen as sky energy carrier wave is not the frequency that is used in communication by the A of North America or the current branch of B service supplier.Therefore, not have direct losses be the power system capacity of other purpose in this distribution.In reality, the carrier frequency 824.4MHz of close this carrier wave is because adjacent-channel interference may be unavailable.Even in this case, thereby, a channel during service supplier A has only lost 416, it only expresses the slight relatively loss of capacity.

Fig. 4 represents the block diagram according to the terminal radio frequency transceiver of the preferred embodiment of the present invention.In transmitter (TX) circuit, the TX base band sources 400 of terminal is at first in frequency mixer 402 and intermediate frequency (IF) local oscillator (LO) 401 mixing, to produce modulated intermediate-freuqncy signal 403.This intermediate-freuqncy signal 403 is exaggerated and filtering 404, and then by 405 frequency displacements of carrier frequency generator to radio frequency carrier frequency, fc for example, this is by control signal 406 controls.An example of carrier-fequency generator is shown among Fig. 5 in more detail.Before the radiofrequency signal of 405 outputs is being sent out the TX port of duplexer 408, be amplified to higher power by power amplifier 407.The antenna 409 of this signal through being connected the duplexer antenna port is sent out away.In receiver (RX) circuit, same, at first by the wireless receiving radiofrequency signal, pass through two formula devices 408 and low noise amplifier (LNA) 410 then.Radiofrequency signal at the LNA410 output is frequency shifted to IF-FRE by the radio frequency local oscillator 412 that is generally the programmable frequency synthesizer in frequency mixer 411.Intermediate-freuqncy signal at frequency mixer 411 outputs is exaggerated and filtering 413, and then by intermediate frequency local oscillator 415 in frequency mixer 414 frequency displacements to base band frequency.Those of ordinary skill in the art will recognize that the miscellaneous equipment that also usually comprises other parts in the reality and also may comprise radio-frequency (RF) transceiver.Although the equipment of the radio-frequency (RF) transceiver of terminal can change, basic function and shown in Figure 4 being consistent.

Fig. 5 is the block diagram of expression according to the further parts of terminal of the preferred embodiment of the invention.Have only radiating circuit to be illustrated, and illustrate in greater detail an example of carrier-fequency generator 405.Fig. 5 also shows a mobile phone 565, microcontroller 550 and the parts to the terminal power supply that will will describe below.In Fig. 5, carrier-fequency generator 405 comprises 505, two local oscillators 506 of a frequency mixer and 520, reaches the switch 521 that a selection is applied to the local oscillator of frequency mixer 505.During communication cycle 201, switch 521 selects radio frequency local oscillator 506 to go this intermediate-freuqncy signal of frequency displacement to desired carrier frequency fc.Radio frequency local oscillator 506 is variable local oscillator sources, programmable frequency synthesizer for example, and the frequency of Chan Shenging equals fc-f in this example _IF, wherein fc selects from available communication channel.During 202 and 203, switch 521 selects local oscillator 520 frequency displacement intermediate-freuqncy signals to the empty energy carrier frequency fw that sends.Local oscillator 520 is that a generation frequency equals fw-f _IFFixedly local oscillator source, supposed only to distribute a single empty energy carrier frequency.Those of ordinary skill in the art should understand, have with a suitable frequency mixer be tuned to equal f _wTf _iThe machine oscillator 520 of f and be tuned to equal f _c+ f _IfThe radio frequency local oscillator be a kind of replacement that is equal to.In operation, controller (550) triggers the switch 521 between radio frequency 506 and 521, or in other words, whether according to having information to be sent out, selecting to send terminal is at fc or at fw.

Because the terminal of Fig. 5 is almost always sending radio-frequency (RF) energy, so it has consumed the more electrical power than conventional TDMA.If this terminal is battery-powered, this higher power consumption has reduced call duration time.Therefore, in fixing wireless multiple access was used, terminal generally contained an AC adapter by the ac main power power supply, and the reserve battery that only just uses when mains power failure.Therefore high power consumption is not big problem for the fixed wireless connecting terminal, unless fault occurs exchanging.So the preferred embodiments of the present invention shown in Figure 5 will work in the electric mode of drawing during AC power failure.As shown in Figure 5, an ac sensor will detect the fault of alternating current, and trigger switch 533 selects battery as power supply when this power failure, and send a signal and go this terminal is transferred to battery saving mode to controller 550.When battery saving mode is worked, during cycle 202 and 203, switch 521 will not received local oscillator 520, and in addition, whole radiating circuit can also be de-energized during cycle 202 and 203.Therefore in battery saving mode, preferred embodiment sends same radiofrequency signal, and consumes as the as many electrical power of ordinary terminal.Although this terminal can produce object electrical appliance as much as conventional terminal in battery saving mode interference is owing to most of household electrical appliance can not be worked during AC power failure, so it can not become a serious problem.Further, this system can constitute with switch, an at user option switch, if this user involves for some equipment, as the interference of hearing aids etc., then it can prevent with battery saving mode work.This switch can be by the control signal quilt alternately straighforward operation of the control centre in wireless network through the Radio Link transmission.

The present invention is not limited only to the wireless system to TDMA, also can be applicable to carry out other system of discontinuous transmission or voice activity detection.Therefore Fig. 5 shows a voice activity detection (VAD) assembly 570, is used to detect the speech whether physical presence is produced by mobile phone 565.Whether VAD570 send an indication to give microcontroller then, have speech to occur, and sends all signals from mobile phone to base band and intermediate frequency piece 560 simultaneously.Carry out voice activity detection unless should be noted that this system, otherwise do not need voice activity detection module 570.

Fig. 6 represents to be used for CDMA digital cellular terminal according to telecommunications industry association's IS-95 standard, utilizes the cycle of the radio-frequency radiation of code division multiple access (CDMA) terminal.This system is designed to adopt the advantage of speech pause to go to increase the easy of system.The IS-95 terminal comprises the device of the speech activity that is used to detect output.During cycle 610,611 when speech information occurs, this terminal is launched communication carrier frequency fc continuously.During cycle 612 when speech pause, this terminal enters the break transfer mode.In this mode, out of Memory, for example control information and/or in 2.5mS pulse train 613,614 and 615, be sent out the interval 616,617,618 of each pulse train 20mS with fc about the information of figure viewed from behind noise.These pulse trains represent to compare with voice messaging the amount of minimizing, and are sent out in irregular position in the interval of 20mS.In cdma system, capacity (number of terminals of the shared carrier frequency of energy) is enhanced by the average power that occurs on channel.The capacity of IS-95 system is by interrupted transmission means thereby be increased, this be because since many terminal operations in carrier frequency fc, the total mean power of being seen by a base station or mesh station machine receipts machine at frequency f c has been reduced when making in this way in these terminals (mutually not side by side).Thereby, the result, above-mentioned amplification demodulation is disturbed and may be occurred near in near the electronic equipment the given wireless terminal of the radio frequency interference ripple that is subjected to this radiation, becomes unstable every 20mS total during speech pause and causes unwanted influence.

Fig. 7 represents from the radiation in the improved IS-95 wireless terminal that uses mode of the present invention.During the cycle 710,711 that voice messaging occurs, this terminal is as among Fig. 6, and fc sends continuously with the communication carrier frequency.During cycle 712 when speech pause, this terminal enters with regard to different mode.In this pattern, the amount of information of minimizing is sent out on 2.5mS pulse train 713,714 and 715, occurs a pulse train on the off side in the interval 716,717,718 of every 20mS.Therefore, during the time interval 720,721 and 722 of remaining cycle 716,717 and 718, this terminal is transferred to sky energy carrier wave fw, and with identical power level it to use that carrier wave fc sends.In practice, exist cycle (not shown) very of short duration before and afterwards at each pulse train 720,721 and 722, radio-frequency radiation must be closed and the conversion back and forth between fw of this frequency at this.If this period ratio pulse train 713,714 and 715 (2.5mS) much shorter, the duty cycle of all during speech pause more approaches 100% of Fig. 6 situation so, therefore can see that from above the influence of interference has been reduced.

As shown in Figure 8, an alternative embodiment of the invention is particularly suitable for using the cdma system of frequency hopping or VAD.In this case, during the cycle 810 when information is sent out, this wireless terminal sends the mode of information at one group of carrier frequency f with the frequency hopping from a carrier wave to another carrier wave randomly with at each carrier wave ₁-f _nTransmission information on 812.In this system, by reducing by a given terminal in frequency f ₁-f _nOn the transmitting time amount and increased the capacity of system.In this mode, use two terminals of same frequency to reduce at one time with " colloidal state " possibility.In frequency f ₁-f _nThe time amount of tiding over that sends utilizes break transfer to be reduced.During cycle 814 when information is not sent out, for example when detecting speech activity indication speech pause and work as out of Memory, when for example the information of figure viewed from behind noise level and control information did not need to be sent out, this terminal was transformed into sky energy carrier wave f _w816 also continue with the same power emission in the last cycle.Therefore, near 100%, and reality has been utilized communication carrier f from the duty cycle of the RF envelope of a wireless terminal radiation ₁-f _n, and therefore this power system capacity, keeping and conventional frequency hopping, discontinuous transmission communication is the same.

Those of ordinary skill in the art will understand, use TDMA and another interrupted transmission at one, and then in both wireless system, the present invention can use tdma slot and this break transfer in a given time slot as the speech activity inspection.For example, in a typical this system, this wireless terminal can be assigned with a time slot that normally appears in the frame.Application of the present invention can comprise having a terminal that is transformed into sky energy carrier wave, and continues emission during other time slot of this frame.For VAD, if this terminal at its oneself time slot with there are not voice to occur, then also can send information.Application of the present invention can comprise also having the terminal that is transformed into the customization amount, and continues emission during the own time slot in the cycle that does not have voice messaging to occur and do not need when information to be sent out.

For Fig. 5, should know to be included in this terminal and unshowned other parts and other improvement are possible.

Controller has determined whether that information is according to TDMA, voice activity detection or cause other agreement of discontinuous transmission to be transmitted in some tdma systems as is known in the art, the experiment suggestion, if the terminal capabilities of Fig. 5 is reinforced during the time slot when transmitter does not send information, then empty energy carrier wave uses the pseudorandom that is similar to the modulation type when occurring in the information transmission modulated.This pseudo-random data can be produced by controller, and delivers to baseband block through the control signal (not shown), perhaps resemble know in the prior art directly in baseband block, produce.

Those of ordinary skill in the art will understand that the realization that substitutes is possible; For example, if radio frequency local oscillator 506 can be at f during interval 210 and 211 _w-f _IFWith f _c-f _IFBetween frequency displacement apace, then switch 521 and local oscillator 520 are just unnecessary.In this case, carrier-fequency generator 405 only comprises frequency mixer 505 and the fast moving radio frequency local oscillator of being controlled by controller.

As the situation that another kind is particularly suitable for substituting, because the interference volume that produces in being subjected to jamming equipment that this carrier frequency modulation is caused by the different capacity level can be left in the basket, carrier-fequency generator 405 can be by following formation so.Local oscillator 520 produces the whole signal f that directly amplifies by power amplifier 507 _wIn this case, have only radio frequency local oscillator 506 to be connected to frequency mixer 505, and switch 521 is moved, is connected to power amplifier 507 so that it is connected to local oscillator 520 or whether is sent out from the output of frequency mixer 505 according to information.

Substitute as another kind, the present invention can take to be used for zero intermediate frequency or quadrature modulation realizes.

Described it and be applied to cause the particular type of interference in household electrical appliance although should be known in the preferred embodiments of the present invention, the present invention also can be used to reduce the unwanted interference of other form that is produced by interrupted transmission.

Various other improvement change and revise and can carry out above-mentioned inventive embodiments under the scope that does not break away from claim definition of the present invention.

Claims (19)

1, a kind of method that reduces the generation interference that is caused by transmitter in the wireless communication system that uses interrupted information to send in electronic equipment comprises step:

(a) determine when information will be sent out;

(b) when information will be sent out this transmitter be tuned to a carrier frequency being used to communicate by letter; With

(c) when information is not sent out described transmitter be tuned to another carrier frequency.

2, method as claimed in claim 1, wherein this transmitter is used in the tdma system, and goes determining step (a) according to the tdma slot of distributing to described transmitter.

3, method as claimed in claim 1, wherein this transmitter is used to contain in the terminal of voice activity detection system, and when voice activity was arranged, step (a) comprised the detection step.

4, method as claimed in claim 3, wherein step (a) determines whether the step that out of Memory wants ripple to send when further being included in voice activity.

5, method as claimed in claim 3, wherein said transmitter is used to a plurality of carrier frequency and is used to communicate by letter and has at least in the frequency-hopping system that a frequency is not used to communicate by letter, and wherein step (b) comprises the step of selecting one of described a plurality of carrier frequency, and step (c) comprises the step of described at least one frequency of selection as one of described other carrier wave.

6, method as claimed in claim 1, wherein said transmitter comprises an intermediate-freuqncy signal source, be used to produce be suitable for any will transmission information an intermediate-freuqncy signal of modulation, a variable local oscillator source, be used to produce a plurality of frequencies, a frequency mixer that is connected with described variable local oscillator source with described intermediate-freuqncy signal source, and step wherein (b) comprises tuning described variable local oscillator source to a frequency, so that this frequency mixer produces the step of a carrier frequency that is used to communicate by letter, and wherein step (c) comprises tuning described variable local oscillator source to a frequency, so that this frequency mixer produces the step of described another carrier frequency.

7, method as claimed in claim 6 further comprises step:

When will being sent out, information modulates described intermediate-freuqncy signal with the information that will be sent out; With

When not having information to be sent out, use pseudorandom, at random or one group of described intermediate-freuqncy signal of bit mode data-modulated.

8, method as claimed in claim 2, wherein this transmitter is used to contain in the terminal of voice activity detection system, and step (b) further is included in and detects the step that whether has the out of Memory that voice maybe will send during the time slot of giving described transmitter.

9, method as claimed in claim 1, wherein said transmitter comprises one first and second source oscillation signal, be used for intermediate-freuqncy signal of suitably modulating of frequency displacement, and step wherein (b) comprises that described first local oscillator and the step (c) selecting to be used for described frequency displacement comprise described second local oscillator of selecting to be used for described frequency displacement.

10, a kind of interrupted transmission transmitter comprises:

A carrier-fequency generator is used for producing one first carrier frequency and is used for producing one second carrier frequency when not having information to send when information will be sent out; With

A controller is used for driving described carrier-fequency generator and produces described first carrier frequency and produce described second carrier frequency when information is not sent out when information will be sent out.

11, as the interrupted transmission transmitter of claim 10, wherein said carrier-fequency generator comprises:

The first frequency path is used to produce one first carrier frequency that will send;

The second frequency path is used to produce a second frequency path that will be sent out; With

A switch responds described controller, is used for selecting between first and second frequency paths.

12, as the transmitter of claim 11, wherein said transmitter further comprises an IF-FRE source, and said IF-FRE source produces the intermediate-freuqncy signal that is suitable for by the information modulation that will send; With

A frequency mixer that is connected with described switch is used for the described intermediate-freuqncy signal of frequency displacement;

And wherein said first frequency path comprises one first local oscillator source, and it produces one and equals the frequency that described first carrier frequency deducts described intermediate-freuqncy signal frequency, and is coupled to described frequency mixer when being selected by described switch;

And wherein said second frequency path comprises one second local oscillator source, and it produces one and equals the frequency that described second carrier frequency deducts described intermediate-freuqncy signal frequency, and is coupled to described frequency mixer when being selected by described switch.

13, as the transmitter of claim 12, wherein said controller when selected, is modulated described intermediate-freuqncy signal with pseudo-random data in described second path.

14, as the transmitter of claim 11, wherein said first frequency path further comprises:

An IF-FRE source, described IF-FRE source produce by sending suitably intermediate-freuqncy signal of modulation of information;

One first local oscillator source, it produces and equals the frequency that described first carrier frequency deducts described intermediate-freuqncy signal frequency; With

A frequency mixer is used for the described IF-FRE signal of frequency displacement, and described frequency mixer is coupled to the described first local oscillator source;

And wherein said second frequency path comprises one the second local oscillator source that is used to produce described second frequency.

15, as the transmitter of claim 10, further comprise:

An AC power source adapter is used to be connected to AC power;

A transducer is used to detect the fault of this AC power;

A reserve battery responds described transducer, is used for to described transmitter power supply; Wherein

Described controller responds described transducer, is used for when not having information to send described transmitter and does not launch, and enters energy-saving mode and change described transmitter.

16,, comprise that further the side of being used for abandons the switch of described energy-saving mode as the transmitter of claim 15.

17, as the transmitter of claim 10, further comprise a voice activity detection unit, whether be used for detection has voice signal to transmit and the signaling link from described unit to described controller.

18, as the transmitter of claim 11, further comprise:

An AC power source adapter is used to be connected to AC power;

A transducer is used to detect the fault of AC power; With

A reserve battery responds described transducer, is used for to described transmitter power supply; Wherein

Described controller responds described transducer, is used for when not having information to send described transmitter and does not launch, and enters energy-saving mode and change described transmitter.

19, as the transmitter of claim 18, further comprise a voice activity detection unit, whether be used for detection has voice signal to transmit and the signaling link from described unit to described controller.

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