CN101141141A - Digital communication frequency deviation eliminating method and device using the same - Google Patents
Digital communication frequency deviation eliminating method and device using the same Download PDFInfo
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- CN101141141A CN101141141A CNA2007100740006A CN200710074000A CN101141141A CN 101141141 A CN101141141 A CN 101141141A CN A2007100740006 A CNA2007100740006 A CN A2007100740006A CN 200710074000 A CN200710074000 A CN 200710074000A CN 101141141 A CN101141141 A CN 101141141A
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Abstract
The present invention discloses a method to eliminate digital communication frequency deviations and a device applying the method. The device to eliminate digital communication frequency deviations firstly carries out coherent demodulation to RF signals, tracks phase positions of two paths of I/Q frequency deviation signals to confirm to output an effective path of signal and outputs the signal after polarity selection is restored. In addition, the method to eliminate digital communication frequency deviations dynamically tracks phase position of the I/Q signal and promptly switches the signal onto an effective signal as frequency deviation exists between a local clock source and a transmitting clock source after coherent demodulation, in particular drastic frequency deviations. Moreover, the method compensates whether the signal polarity is turned over in real time according to a relation between phase position and polarity and outputs restored correct effect signals. Certainly, the present invention is also suitable for eliminating different frequency of transmission and receiving clocks resulting from other reasons in the field of communication.
Description
Technical field
The present invention relates to digital communicating field, in particular, relate to the method that digital communication frequency deviation eliminates and make in this way device.
Background technology
In digital communicating field, demodulation mode can be divided into two big classes, i.e. coherent demodulation and non-coherent demodulation basically.The former extracts modulation signal from the phase information of modulated wave, the latter extracts them from the amplitude information of modulated wave.Because coherent demodulation requires receiver that a local reference carrier with carrier frequency synchronization is provided, so can be described as synchronous demodulation again.When adopting coherent demodulation, the receiving terminal local oscillator needs and sends signal(-) carrier frequency with frequently, if frequency has deviation, receiving terminal will demodulate difference frequency signal (if local frequency is f0, when the transmission signal frequency is f0+ Δ f, when Δ f drops in the baseband signal bandwidth, the signal that can to demodulate a frequency be Δ f), this signal is modulated on the useful signal, not only can cause the variation of signal amplitude, but also might cause the change in polarity of signal, the correctness and the stability of communication has been caused very big influence.
If receiving terminal and to send the frequency difference of signal(-) carrier frequency very little, communication time be less than 1/4 wavelength of the difference frequency signal that produces, at present the method that adopts can be by the signal of selecting demodulator to come out strong a road, can finish communication.When frequency difference was big, the method applicability was very poor: when the 100Hz, the effective communication time that the signal phase upset can not occur is 2.5ms as frequency difference.If frequency difference is bigger, during as 10KHz, the effective communication time that the signal phase upset can not occur is 25us, if the baseband signal phase overturn that communication time greater than 25us, will occur demodulating is made mistakes demodulation.
Summary of the invention
For overcoming above-mentioned defective, technical problem to be solved by this invention provides a kind ofly can be eliminated the method for eliminating than the digital communication frequency deviation of large frequency-difference and make in this way device.
The objective of the invention is to be achieved through the following technical solutions:
The method that a kind of digital communication frequency deviation is eliminated may further comprise the steps:
Step 1 is carried out coherent demodulation to the radiofrequency signal of input, demodulates the two-way i/q signal;
Step 2, the phase place of following the tracks of the difference frequency signal of two-way i/q signal is to determine effective one road signal of output;
Step 3 is carried out polarity to effective one road signal of exporting in the step 2 and is selected to recover, and output.
On the basis of the above, wherein:
In the described step 2, may further comprise the steps:
Step 21 is with the i/q signal that demodulates in the step 1 low-pass filtering in time window respectively;
Step 22 is carried out the phase bit comparison to the filtered I/Q two paths of signals that obtains in the step 21, judges the current useful signal that should choose;
Step 23 according to the useful signal that obtains in the step 22, is selected effective one road signal in the I/Q road signal of coherent demodulation module output, carry out bit synchronization signal and recover, by the time window of filtering in the bit synchronization signal controlled step 21 that recovers;
Step 24 according to the judged result that obtains in the step 22, is selected the output of one road useful signal in the filtered signal of I/Q two-way that obtains in step 21.
In the described step 3, may further comprise the steps:
Step 31 compares useful signal and the reference level that obtains in the step 24, carries out 0/1 judgement, exports digital 0/1 signal;
Step 32 is carried out polarity to the filtered signal of I/Q two-way that obtains in the step 21 and is judged, judges whether the current signal output polarity of choosing should overturn;
Step 33 according to the polarity judged result that obtains in the step 32, is carried out polarity with numeral 0/1 signal that obtains in the step 31 and is recovered, and obtains and export correct digital signal.
Further, the two-way i/q signal that demodulates in the described step 1 is a quadrature.Certainly, the phase difference between the two-way i/q signal that demodulates can be other angles, as 60 °, and 120 ° etc., but its effect of eliminating frequency deviation is best with the i/q signal of quadrature.
Low-pass filtering in the described step 21 is by realizing the i/q signal integration respectively.
In the described step 23, it is by extracting the bit synchronization pulse of effective one road signal that bit synchronization signal recovers, the accumulated level of removing during to I/Q two paths of signals integration realize, the time window of the bit synchronization pulse shaping integration of adjacent accumulated level when removing integration twice.
In the described step 22, define the method for imitating signal by the phase bit comparison and may further comprise the steps:
Step 221: in time window, compare the integration amplitude of I/Q two paths of signals, determine the phase place of difference frequency signal according to the amplitude difference between the i/q signal;
Step 222: according to the phase place of difference frequency signal, determine useful signal, [M, N] between the phase place of difference frequency signal and default phase region compared, when phase place is selected the signal output of I road less than M or phase place during greater than N, otherwise select the signal output of Q road; Wherein, the selection of M and N need make signal when the Q road, and at M, polarity is not overturn in the scope of N, in the signal of I road, does not overturn less than M or greater than signal polarity in the N scope simultaneously yet.
In step 32, when the I/Q two-way integral result that obtains in the step 21 is carried out the polarity judgement,, then be judged as not negate if the polarity of I/Q two-way integral result is identical, corresponding, numeral 0/1 signal that will obtain in step 33 is directly exported; If the polarity of I/Q two-way integral result is opposite, then be judged as negate, corresponding, the numeral 0/1 signal negate output that in step 33, will obtain.
Reference level in the described step 31 is the level at zero point.
A kind of device that uses the digital communication frequency deviation elimination of said method, wherein: the device that described digital communication frequency deviation is eliminated comprises:
Carry out the filtration module that i/q signal is carried out filtering respectively that coherent demodulation becomes the radio frequency of i/q signal to receive the coherent demodulation module, be connected with radio frequency reception coherent demodulation module by signal to the received signal,
With filtered i/q signal carry out the phase bit comparison the phase bits comparison module,
With filtered i/q signal carry out polarity judge module that polarity judges,
The selection output module that connects with bits comparison module signal mutually,
0/1 judging module that is connected with selection output module signal,
By polarity judge module control, the result of 0/1 judging module carried out selectivity is recovered and the polarity of exporting correct result is recovered module,
With by the control of bits comparison module mutually, receive with radio frequency that the coherent demodulation module by signal is connected, the synchronizing signal recovery module that filtration module is controlled;
Bits comparison module, polarity judge module, selection output module signal connect filtration module respectively with mutually.
The device of the present invention by using digital communication frequency deviation to eliminate carries out coherent demodulation to radiofrequency signal, and the phase place of the difference frequency signal of the two-way i/q signal that goes out by trace demodulation is to determine effective one road signal of output; And carrying out polarity selection recovery back output.Make when there are frequency difference in the local clock source of coherent demodulation and transmit clock source, when especially frequency difference is bigger, can follow the tracks of the phase place of i/q signal dynamically, in time switch on the useful signal, and in real time whether the polarity of signal is overturn according to the relation of phase place and polarity and to compensate the correct useful signal that output recovers.Certainly, the present invention is applicable to that also other reason causes the different situations frequently of receive clock that send in the communications field.
Description of drawings
Fig. 1 is the frequency difference cancellation module figure of the embodiment of the invention.
Wherein: 101, radio frequency receives the coherent demodulation module, 102, I road signal integration module, 103, Q road signal integration module, 104, phase bits comparison module, 105, polarity judge module, 106, select output module, 107, synchronizing signal recovers module, 108,0/1 judging module, 109, polarity recovers module.
Embodiment
The invention will be further described below in conjunction with accompanying drawing and preferred embodiment.
As shown in Figure 1, the device of digital communication frequency deviation elimination comprises: carry out coherent demodulation to the received signal and become the radio frequency of two-way I/Q baseband signal to receive coherent demodulation module 101; Receive with radio frequency that coherent demodulation module 101 signals are connected, the I road signal that demodulates is carried out the I road signal integration module 102 of integration and the Q road signal that demodulates carried out the Q road signal integration module 103 of integration; I/q signal behind the integration is carried out the phase bits comparison module 104 of phase bit comparison; I/q signal behind the integration is carried out the polarity judge module 105 that polarity is judged; The selection output module 106 that connects with bits comparison module 104 signals mutually; With 0/1 judging module 108 of selecting output module 106 signals to be connected; By polarity judge module 105 control, the result of 0/1 judging module 108 carried out selectivity is recovered and the polarity of exporting correct result is recovered module 109; With by 104 controls of bits comparison module mutually, I road signal is carried out the I road signal integration module 102 of integration and Q road signal is carried out the synchronizing signal that the Q road signal integration module 103 of integration controls simultaneously recover module 107; Bits comparison module 104, polarity judge module 105, selection output module 106 signals are connected I road signal integration module 102 simultaneously with mutually respectively with Q road signal integration module 103.
The method that the device that uses this digital communication frequency deviation to eliminate is eliminated digital communication frequency deviation is as follows:
Radio frequency reception coherent demodulation module 101 radiofrequency signals with input are demodulated into the baseband signal of I/Q two-way, output to I road signal integration module 102 and Q road signal integration module 103 respectively.
To I, the Q two paths of signals carries out integration respectively in the preset time window mouth for I road signal integration module 102 and Q road signal integration module 103.When coming, removes the lock-out pulse of synchronizing signal recovery module 107 accumulated level of I road signal integration module 102 and Q road signal integration module 103 integrates devices, carrying out bit synchronization signal recovers, per two adjacent lock-out pulses form the synchronous time window of I road signal integration modules 102 and Q road signal integration module 103, make in this time window, I, Q two paths of signals just pass through the information of a position (bit) simultaneously.I road signal integration module 102 is sent bits comparison module 104 mutually respectively with the integral result that Q road signal integration module 103 obtains, and polarity judge module 105 is selected output module 106.
Phase bits comparison module 104 is according to the phase place of the integration amplitude difference between the i/q signal with definite difference frequency signal, phase place according to difference frequency signal, determine useful signal, with [M between the phase place of difference frequency signal and default phase region, N] compare, when phase place is selected the I road signal output selection signal of high level (as send) during greater than N less than M or phase place, otherwise select Q road signal output (as sending low level selection signal).The selection of M and N need make signal when the Q road, and at M, polarity is not overturn in the scope of N, in the signal of I road, does not overturn less than M or greater than signal polarity in the N scope simultaneously yet.
For example: when I road signal during than big 2 times of Q road signal, just | cos (A) |＞2|sin (A) |, can think that the phase place of difference frequency signal is between the phase region of (26.6～26.6) and (153.43～206.6), this moment, useful signal should be selected the I road, with should 2|cos (A) |＜| sin (A) | the time, useful signal is selected the Q road.If | cos (A) |＜2|sin (A) | and 2|cos (A) |＞| sin (A) | in the time of between phase region, the signal that keeps selecting at that time is a useful signal.Certainly, amplitude difference also can be selected other proportionate relationship.
Selection output module 106 is selected i/q signal output according to the output result of phase bits comparison module 104.Be that phase bits comparison module 104 is judged when the I road is effective (the selection signal that receives is a high level), the integral result of selecting output module 106 outputs to obtain from I road signal integration module 102, otherwise, the integral result that output obtains from Q road signal integration module 103.
Synchronizing signal is recovered the result of module 107 according to phase bits comparison module 104, in the I/Q two-way fundamental frequency signal of input, select effective one road signal, as, when phase bits comparison module 104 result relatively is I road when effective (the selection signal that receives is a high level), then synchronizing signal is recovered the bit synchronization signal when last position signal that module 107 is extracted I roadbed frequency signal, form a pulse, be sent to I road signal integration module 102 and Q road signal integration module 103 simultaneously, make the integrator zero clearing, to realize control to the window time of integration.
0/1 decision device 108 will select output module 106 output useful signal the level integrated value with zero point level ratio, the level of judgement useful signal is 0 or 1.
Polarity judge module 105 is according to the result of I road signal integration module 102 and Q road signal integration module 103 output, output 0 when the polarity of two paths of signals integration module is identical, otherwise export 1.Corresponding, polarity is recovered module 109 and according to polarity judge module 105 output results 108 output negates of 0/1 decision device or not negate is handled.When being output as 0,0/1 decision device 108, polarity judge module 105 exports not negate, otherwise negate.Last output is numeral 0/1 signal that recovers polarity.Certainly, output 1 when the polarity judge module is also can be in the polarity of two paths of signals integration module identical does not export 0 simultaneously, as long as 0/1 decision device 108 is exported not negate when the polarity of two paths of signals integration module is identical, otherwise 0/1 decision device, 108 negates output gets final product.
Because it is a kind of of low-pass filtering that signal is carried out integration, can also realize this programme by other low pass filter.When phase bits comparison module 104 is determined the phase place of difference frequency signal, then can judge by the intensity difference of more filtered signal.
Above content be in conjunction with concrete preferred implementation to further describing that the present invention did, can not assert that concrete enforcement of the present invention is confined to these explanations.As: the two-way i/q signal that demodulates can be a quadrature, and the phase difference of certain other also can be arranged, as 60 °, 120 ° etc.; Reference level can be chosen as the level at zero point, also can select other reference level according to actual conditions, as long as can effectively rule out 0/1 signal.For the general technical staff of the technical field of the invention, without departing from the inventive concept of the premise, the some simple deduction or replace of making all should be considered as belonging to protection scope of the present invention.
Claims (10)
1. the method eliminated of a digital communication frequency deviation may further comprise the steps:
Step 1 is carried out coherent demodulation to the radiofrequency signal of input, demodulates the two-way i/q signal;
Step 2, the phase place of following the tracks of the difference frequency signal of two-way i/q signal is to determine effective one road signal of output;
Step 3 is carried out polarity to effective one road signal of exporting in the step 2 and is selected to recover, and output.
2. the method that a kind of digital communication frequency deviation as claimed in claim 1 is eliminated is characterized in that: in the described step 2, may further comprise the steps:
Step 21 is with the i/q signal that demodulates in the step 1 low-pass filtering in time window respectively;
Step 22 is carried out the phase bit comparison to the filtered I/Q two paths of signals that obtains in the step 21, judges the current useful signal that should choose;
Step 23 according to the useful signal that obtains in the step 22, is selected effective one road signal in the I/Q road signal of coherent demodulation module output, carry out bit synchronization signal and recover, by the time window of filtering in the bit synchronization signal controlled step 21 that recovers;
Step 24 according to the judged result that obtains in the step 22, is selected the output of one road useful signal in the filtered signal of I/Q two-way that obtains in step 21.
3. the method that a kind of digital communication frequency deviation as claimed in claim 2 is eliminated is characterized in that: in the described step 3, may further comprise the steps:
Step 31 compares useful signal and the reference level that obtains in the step 24, carries out 0/1 judgement, exports digital 0/1 signal;
Step 32 is carried out polarity to the filtered signal of I/Q two-way that obtains in the step 21 and is judged, judges whether the current signal output polarity of choosing should overturn;
Step 33 according to the polarity judged result that obtains in the step 32, is carried out polarity with numeral 0/1 signal that obtains in the step 31 and is recovered, and obtains and export correct digital signal.
4. the method that a kind of digital communication frequency deviation as claimed in claim 1 is eliminated, it is characterized in that: the two-way i/q signal that demodulates in the described step 1 is a quadrature.
5. the method that a kind of digital communication frequency deviation as claimed in claim 3 is eliminated, it is characterized in that: the low-pass filtering in the described step 21 is by realizing the i/q signal integration respectively.
6. the method that a kind of digital communication frequency deviation as claimed in claim 5 is eliminated, it is characterized in that: in the described step 23, it is by extracting the bit synchronization pulse of effective one road signal that bit synchronization signal recovers, the accumulated level of removing during to I/Q two paths of signals integration realize, the time window of the bit synchronization pulse shaping integration of adjacent accumulated level when removing integration twice.
7. the method that a kind of digital communication frequency deviation as claimed in claim 5 is eliminated is characterized in that: in the described step 22, define the method for imitating signal by the phase bit comparison and may further comprise the steps:
Step 221: in time window, compare the integration amplitude of I/Q two paths of signals, determine the phase place of difference frequency signal according to the amplitude difference between the i/q signal;
Step 222: according to the phase place of difference frequency signal, determine useful signal, [M, N] between the phase place of difference frequency signal and default phase region compared, when phase place is selected the signal output of I road less than M or phase place during greater than N, otherwise select the signal output of Q road; Wherein, the selection of M and N need make signal when the Q road, and at M, polarity is not overturn in the scope of N, in the signal of I road, does not overturn less than M or greater than signal polarity in the N scope simultaneously yet.
8. the method that a kind of digital communication frequency deviation as claimed in claim 5 is eliminated, it is characterized in that: in step 32, when the I/Q two-way integral result that obtains in the step 21 is carried out the polarity judgement, if the polarity of I/Q two-way integral result is identical, then be judged as not negate, corresponding, numeral 0/1 signal that will obtain in step 33 is directly exported; If the polarity of I/Q two-way integral result is opposite, then be judged as negate, corresponding, the numeral 0/1 signal negate output that in step 33, will obtain.
9. the method that a kind of digital communication frequency deviation as claimed in claim 5 is eliminated, it is characterized in that: the reference level in the described step 31 is the level at zero point.
10. one kind is used the device of the digital communication frequency deviation elimination of method according to claim 1, and it is characterized in that: the device that described digital communication frequency deviation is eliminated comprises:
Carry out to the received signal coherent demodulation become the radio frequency of i/q signal receive the coherent demodulation module,
The filtration module that i/q signal is carried out filtering respectively that receives that the coherent demodulation module by signal is connected with radio frequency,
With filtered i/q signal carry out the phase bit comparison the phase bits comparison module,
With filtered i/q signal carry out polarity judge module that polarity judges,
The selection output module that connects with bits comparison module signal mutually,
0/1 judging module that is connected with selection output module signal,
By polarity judge module control, the result of 0/1 judging module carried out selectivity is recovered and the polarity of exporting correct result is recovered module,
With by the control of bits comparison module mutually, receive with radio frequency that the coherent demodulation module by signal is connected, the synchronizing signal recovery module that filtration module is controlled;
Bits comparison module, polarity judge module, selection output module signal connect filtration module respectively with mutually.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018153109A1 (en) * | 2017-02-24 | 2018-08-30 | 京东方科技集团股份有限公司 | Adjustment method and adjustment apparatus for display panel, and display apparatus |
| CN113050101A (en) * | 2019-12-26 | 2021-06-29 | 宁波飞芯电子科技有限公司 | Coherent signal receiving device, method and coherent detection system |
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| CN1290280C (en) * | 2002-12-31 | 2006-12-13 | 上海贝尔阿尔卡特股份有限公司 | Method of self eliminating interference between self adaptive carriers and receiving and transmitting machine |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018153109A1 (en) * | 2017-02-24 | 2018-08-30 | 京东方科技集团股份有限公司 | Adjustment method and adjustment apparatus for display panel, and display apparatus |
| US11263990B2 (en) | 2017-02-24 | 2022-03-01 | Boe Technology Group Co., Ltd. | Method and device for adjusting display panel, and display device |
| CN113050101A (en) * | 2019-12-26 | 2021-06-29 | 宁波飞芯电子科技有限公司 | Coherent signal receiving device, method and coherent detection system |
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