CN101179545A - Doppler frequency cancellation based full digital main carrier tracking method - Google Patents
Doppler frequency cancellation based full digital main carrier tracking method Download PDFInfo
- Publication number
- CN101179545A CN101179545A CNA2007101799740A CN200710179974A CN101179545A CN 101179545 A CN101179545 A CN 101179545A CN A2007101799740 A CNA2007101799740 A CN A2007101799740A CN 200710179974 A CN200710179974 A CN 200710179974A CN 101179545 A CN101179545 A CN 101179545A
- Authority
- CN
- China
- Prior art keywords
- msub
- mrow
- signal
- complex
- doppler frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000001228 spectrum Methods 0.000 claims abstract description 39
- 238000005259 measurement Methods 0.000 claims abstract description 33
- 230000010355 oscillation Effects 0.000 claims description 13
- 238000005070 sampling Methods 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 230000008030 elimination Effects 0.000 claims description 6
- 238000003379 elimination reaction Methods 0.000 claims description 6
- 230000001934 delay Effects 0.000 claims description 3
- 230000003111 delayed effect Effects 0.000 claims description 3
- 230000035945 sensitivity Effects 0.000 claims description 3
- 230000006854 communication Effects 0.000 abstract description 12
- 238000004891 communication Methods 0.000 abstract description 11
- 238000013461 design Methods 0.000 abstract description 5
- 238000010586 diagram Methods 0.000 description 13
- 230000000694 effects Effects 0.000 description 4
- 239000000969 carrier Substances 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 230000009977 dual effect Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- 238000012937 correction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
Images
Landscapes
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
The invention relates to an all-digital main carrier tracking method based on a Doppler frequency cancellation which belongs to a measurement and control communications field. The invention is characterized in that: by using a characteristic of a frequency spectrum which is dual-modulated by the main carrier and a vice-carrier of a USB measurement and control signal, in the signal of carrying out the main carrier capture and removing most of Doppler frequency difference, a FIR lowpass filter is used for extracting the main carrier signal carrying a negative Doppler rest frequency difference information, a positive-negative cancellation of the Doppler rest frequency difference is completed, and a purpose of tracking the main carrier is reached. The invention overcomes problems of trouble in a ring road structure and parameter design, a Doppler residual error not able to be removed completely in a traditional way of using a phase-locked loop, and thus the invention is suitable for tracking the main carrier in the USB measurement and control system.
Description
Technical Field
The invention relates to a full-digital main carrier tracking method based on Doppler frequency cancellation, which is suitable for main carrier tracking of a Unified S-band (USB) measurement and control signal. The method can better realize the purpose of eliminating the Doppler frequency offset without a feedback control loop. The scheme is particularly suitable for the tracking control of the main carrier under the condition of large Doppler frequency change rate. The method belongs to the field of measurement and control communication.
Background
In the communication process, because the radial movement speed (speed along the straight line direction of the communication objects) often exists between the communication objects, the Doppler effect occurs between the received signal and the transmitted signal, so that the Doppler frequency difference exists; in addition, in most cases, the movement of the communication object is not uniform, which in turn causes a change in the doppler frequency of the received signal, making signal reception more difficult. In terrestrial communications, the doppler effect is less pronounced due to the limitation of the speed of motion. However, in the space measurement and control communication, due to the high-speed motion of the measurement and control object (such as a satellite, a missile, a carrier rocket, and the like), the doppler effect is obvious, so that the signal receiving quality is deteriorated, and even normal receiving cannot be performed. For example, when a spacecraft flies at a high speed in deep space and is measured and controlled by a USB measurement and control system, the information rate of subcarrier communication is 1Kbps, and the maximum Doppler frequency difference and the Doppler change rate which can be achieved are +/-150 KHz and 50KHz/s respectively, which causes that the signal receiving is extremely difficult. Therefore, the method for seeking to resist the doppler effect becomes a research hotspot in the field of measurement and control communication.
The USB measurement and control system adopts a dual modulation mode, that is, each path of measurement and control baseband signal is firstly modulated by sub-carriers such as PSK, FSK, etc., and then is combined together to modulate PM of a main carrier, and a modulated signal spectrum has the main carrier and the sub-carriers, as shown in fig. 1. To combat the large doppler frequencies and frequency change rates, a number of researchers have done a great deal of work, researching and designing a series of methods. The process of eliminating the Doppler frequency difference by the methods is mainly divided into two parts of acquisition and tracking of a main carrier signal. The acquisition of the main carrier mainly completes the identification and approximate positioning of the main carrier in a frequency domain so as to eliminate most Doppler frequency differences; the tracking of the main carrier wave mainly completes the elimination of the residual Doppler frequency difference, thereby completing the correction of all Doppler frequency differences in the measurement and control signal. In the existing USB measurement and control system, the main carrier capture method mainly comprises a frequency scanning method, a frequency spectrum judging symmetry method, a frequency spectrum template matching method, a frequency spectrum energy center method, a frequency spectrum presetting method under the condition of predicting the motion state of a measurement and control object and the like; the tracking of the main carrier basically adopts a phase-locked loop mode, the residual Doppler frequency difference is tracked through the closed loop of the phase-locked loop, and the difference between different designer methods mainly lies in the structural design of the loop and the selection of loop parameters, and the purpose is to reduce the residual frequency residual error as much as possible. The phase-locked loop is used for tracking the residual Doppler frequency difference, the structure is simple, the occupied resources are small, but a certain frequency residual exists all the time, and the Doppler frequency difference cannot be completely eliminated; when the doppler change rate is large, a high-order phase-locked loop is needed to track the change of the doppler frequency, and the design of the high-order phase-locked loop involves the problem of loop stability, so that the implementation is very difficult.
Disclosure of Invention
The invention provides a full digital main carrier tracking method based on Doppler frequency cancellation according to the problems. The method utilizes the frequency spectrum characteristic of dual modulation of a main carrier and a subcarrier of a USB measurement and control signal, extracts a main carrier signal carrying negative Doppler frequency difference information from a complex signal which is subjected to main carrier capture and eliminates most Doppler frequency differences, and performs positive and negative cancellation on the Doppler frequency differences to achieve the purposes of thoroughly eliminating the Doppler frequency differences and completing main carrier tracking. The method is visual and simple, can completely eliminate the Doppler frequency difference under the condition that hardware resources are not increased much, and is not limited by the Doppler change rate.
The invention is characterized in that the method comprises the following steps in sequence:
step (1): the received USB measurement and control band-pass analog signal with the Doppler frequency difference is converted into a digital signal through an analog-to-digital converter.
Step (2): the USB measurement and control band-pass digital signal with the Doppler frequency difference obtained in the step (1) passes through an orthogonal down converter to obtain a complex baseband signal with the Doppler frequency difference, and the real part and the imaginary part of the complex baseband signal are respectively represented by I1、Q1And two paths of data information are represented.
And (3): and (3) enabling the baseband complex signal with the Doppler frequency difference obtained in the step (2) to pass through a main carrier capturing device, and eliminating most of the Doppler frequency difference. The main carrier capturing device firstly outputs I in the step (2)1、Q1Two paths of data are respectively used as a real part and an imaginary part and are combined into a complex number, then fast Fourier transform of N (the selection of N is related to the sampling rate of an analog-digital converter and the resource of hardware) points is carried out, then the absolute value of the transformed result is taken and the correlation operation is carried out on the spectrum template preset in advance, a correlation peak is searched in the set maximum Doppler range, the frequency position corresponding to the correlation peak is the position of a main carrier in the frequency domain, the numerical control oscillator is controlled by the position information of the main carrier to output sine and cosine complex oscillation frequencies, and then the sine and cosine complex oscillation frequencies and an input baseband complex signal (I) with Doppler frequency difference are combined1、Q1Two paths of data are combined) to perform complex multiplication, complete most Doppler frequency difference elimination and output complex signals, wherein the real part and the imaginary part of the complex signals are respectively represented by I2、Q2And two paths of data information are represented. The preset frequency spectrum template is an amplitude frequency spectrum of a single pulse adopted by a known transmitter; the correlation operation refers to the operation of multiplying and summing the sampling points of the corresponding positions of two discrete signals with different relative delays; the maximum doppler range is determined by the radial velocity of the space, typically ± 300 kHz; if the position of the main carrier wave in the frequency domain deviates from zero frequency by a distance D (Hz), the frequency of the two paths of oscillation signals is K x D (Hz), wherein K is the modulation sensitivity of the numerically controlled oscillator and is usually 1; a large doppler frequency difference generally refers to a condition that the maximum residual frequency offset after frequency difference cancellation is less than 16 kHz.
And (4): the complex signals obtained in the step (3) pass through a spectrum symmetry signal former to form two paths of complex signals X with the spectrum being symmetrical left and right about the zero frequency1And X2. The spectrum symmetrical signal generator divides the input complex signal into two paths, one path is directly output without any processing, and X is used1Meaning that one path will input the imaginary part (i.e. Q) of the complex signal2) Multiplied by-1 and then summed with the real part (i.e., I)2) ACombining into a complex output using X2And (4) showing.
And (5): two paths of complex signals obtained in the step (4) are processed by a Doppler frequency cancellation preprocessor to form two paths of complex signals Y1And Y2And (6) outputting. The Doppler frequency cancellation preprocessor processes the complex signal X output in the step (4)2Performing Finite Impulse Response (FIR) low-pass filtering to output main carrier complex signal with negative Doppler frequency information, and using Y2Represents; for the complex signal X output in the step (4)1Performing delay processing to output Y1To ensure that the signal is represented by X2To Y2The required time and the sum of X1To Y1The time required is equal.
And (6): and (4) passing the two paths of complex signals output in the step (5) through a Doppler frequency canceller to obtain a USB measurement and control baseband complex signal with Doppler frequency difference eliminated, and completing the tracking of the main carrier. The Doppler frequency canceller multiplies the two paths of complex signals output in the step (5) to realize Doppler frequency cancellation.
The full digital main carrier tracking method based on Doppler frequency cancellation provided by the invention has the main advantages that: the method is visual and simple, can completely eliminate the Doppler frequency difference under the condition that hardware resources are not increased much compared with the traditional phase-locked loop method, and is not limited by the Doppler change rate.
Drawings
Fig. 1 is a schematic baseband frequency spectrum diagram of a USB measurement and control signal.
Fig. 2 is a block diagram of a general implementation of a main carrier tracking method based on doppler frequency cancellation.
Fig. 3 is a quadrature down conversion block diagram.
Fig. 4 is a block diagram of a primary carrier acquisition apparatus.
Fig. 5 is a block diagram of a spectrally symmetric signal former.
Figure 6 is a block diagram of a doppler frequency cancellation preprocessor.
Figure 7 is a block diagram of a doppler frequency canceller.
Detailed Description
The invention is described in detail below with reference to the accompanying drawings:
fig. 2 is a general block diagram of a main carrier tracking method based on doppler frequency cancellation. As shown in fig. 2. The receiver receives a USB measurement and control band-pass analog signal with Doppler frequency difference, and the USB measurement and control digital complex baseband signal with most Doppler frequency difference eliminated is obtained after the USB measurement and control band-pass analog signal sequentially passes through an analog-to-digital converter, an orthogonal down converter, a main carrier capturing device and the like. The complex baseband signal passes through a spectrum signal generator to obtain two paths of complex signals of which the frequency spectrums are symmetrical left and right about zero frequency; when the two paths of complex signals pass through the Doppler frequency cancellation preprocessor, one path of complex signals is output in a delayed mode, and the other path of complex signals is output after FIR low-pass filtering. And finally, the two paths of output signals pass through a Doppler frequency canceller to obtain a USB measurement and control digital complex baseband signal which can completely eliminate Doppler frequency difference.
The following is the algorithm description of each part and the concrete implementation method thereof:
firstly, the received USB measurement and control band-pass analog signal with Doppler frequency difference passes through an analog-to-digital converter to complete the sampling rate fsThe analog signal is converted into a digital signal by the analog-to-digital conversion. Wherein f issIs related to the maximum doppler frequency offset of the USB measurement and control signal and the maximum information rate of the subcarrier signal, generally fsAt least 2 times larger than the maximum value of the two. For example, if the maximum Doppler shift is + -150 KHz, the maximum information rate of the subcarrier signal is 1Kbps, then fsAt least 300KHz should be chosen, typically over 600 KHz.
Fig. 3 is a quadrature down conversion block diagram. As shown in fig. 3, through the dieThe digital converted USB measurement and control band-pass digital signal with Doppler frequency difference is processed by an orthogonal down converter to obtain a USB measurement and control baseband digital signal with Doppler frequency difference, and the specific implementation method comprises the following steps: multiplying the input signal by the in-phase path and quadrature path signals of the digital controlled oscillator respectively to output I1And Q1。
Fig. 4 is a block diagram of a primary carrier acquisition apparatus. As shown in fig. 4, the baseband signal after the quadrature down-conversion is output after the main carrier is captured by the main carrier capturing device and most of the doppler frequency difference is removed; the specific implementation method comprises the following steps:
(1) firstly, an input baseband signal I after quadrature down-conversion1And Q1The real number/complex number is converted into complex number by a real number/complex number converter, and then fast Fourier transform of N points is carried out to convert the complex number into a frequency domain. Wherein, the selection of the fast Fourier transform point number N is related to the precision P after the conversion to the frequency domain, and P ═ fsand/N, wherein N can be made as large as possible under the permission of hardware resources. For example, at fsIn the case of 800KHz/s, N4096 may be selected.
(2) Taking an absolute value of the frequency spectrum after the fast Fourier transform to obtain an amplitude frequency spectrum, and carrying out correlation operation on the amplitude frequency spectrum and a pre-stored preset frequency spectrum template with different relative frequency offsets to find out the relative frequency offset of the frequency spectrum and the preset frequency spectrum template with the maximum correlation value, namely the position of a correlation peak; therefore, the position of the main carrier is found, and the acquisition process is completed. The preset spectrum template is an amplitude spectrum of a single pulse adopted by a known transmitter, and the correlation operation refers to an operation of multiplying and summing sampling points at corresponding positions of two discrete signals with different relative delays.
(3) And controlling the numerically controlled oscillator to output in-phase and quadrature oscillation signals by using the frequency spectrum position information of the captured main carrier, and converting the in-phase and quadrature oscillation signals into complex oscillation signals through a real number/complex number converter. If the position of the main carrier wave in the frequency domain deviates from the zero frequency by a distance d (hz), the frequency of the two oscillation signals is K × d (hz), where K is the modulation sensitivity of the numerically controlled oscillator, and is usually 1.
(4) The complex oscillation signal output by the oscillator and the input complex baseband signal (I)1And Q1Converted from real number) to complete the elimination of large Doppler frequency difference and convert the result into two paths of real numbers I2And Q2And (6) outputting. Wherein, the large doppler frequency difference generally refers to the condition that the maximum residual frequency offset after the frequency difference elimination is less than 16 kHz.
Fig. 5 is a block diagram of a spectrally symmetric signal former. As shown in FIG. 5, the complex baseband signal (I) with most of the Doppler frequency difference removed2And Q2Respectively as a real part and an imaginary part), and two paths of complex signals X with frequency spectrums symmetrical about zero frequency are formed after passing through a spectrum symmetrical signal former1And X2(ii) a The specific implementation method comprises the following steps:
(1) removing most of Doppler frequency difference from input complex baseband signal (I)2And Q2Respectively, real part and imaginary part) to obtain a complex signal X1。
(2) To be inputted signal Q2Multiplied by-1 as imaginary, input signal I2As the real part, the combined path is a complex signal X2And (6) outputting.
The complex baseband signal after removing most of the doppler frequency difference can be represented as:
wherein wdsM is the number of sub-carriers in the USB system, psi, in order to eliminate most of the residual frequency difference after Doppler frequency differencenFor the nth subcarrier modulation signal, T is the discrete sample time,
denotes Ψ1+Ψ2…+Ψm。
Signal STAfter passing through the spectrum symmetrical signal former, X is output1And X2Comprises the following steps:
figure 6 is a block diagram of a doppler frequency cancellation preprocessor. As shown in FIG. 6, a complex signal X of spectral symmetry1And X2After passing through a Doppler frequency cancellation preprocessor, one path of output complex baseband signal Y for pre-eliminating residual Doppler frequency difference1One output extracted negative Doppler frequency difference complex signal Y2(ii) a The specific implementation method comprises the following steps:
(1) the input frequency spectrum symmetrical complex signal X1And delaying by a delayer, wherein the delay is equal to the delay of the FIR low-pass filter.
(2) To be inputted complex signal X2Filtering with an FIR low-pass filter to output complex signal Y containing negative Doppler frequency difference information2. The selection of the FIR low-pass filter needs to meet two conditions, namely that the bandwidth of the filter cannot be smaller than the maximum residual frequency offset after the elimination of large Doppler frequency offset, and that the bandwidth of the filter cannot be larger than the subcarrier modulation frequency of a subcarrier nearest to the main carrier in the frequency spectrum of the USB measurement and control signal.
Complex signal X1And X2After passing through Doppler frequency cancellation preprocessor, complex signal Y is output1And Y2，
Figure 7 is a block diagram of a doppler frequency canceller. As shown in FIG. 7, the Doppler frequency canceller will pre-cancel the complex baseband signal Y of the residual Doppler frequency difference1And extracting negative Doppler frequency difference complex signal Y2And performing complex multiplication to eliminate the residual Doppler frequency difference and output a signal Z.
Through the steps, the acquisition and tracking of the main carrier wave are finally completed, and the Doppler frequency difference is completely eliminated.
As described above, according to the full digital main carrier tracking method based on doppler frequency cancellation of the present invention, the problems that the existing various USB main carrier tracking methods need to design a phase-locked loop, design a loop structure according to doppler characteristics, and adjust loop parameters are avoided, and the method is simple to implement; compared with the traditional phase-locked loop method, the tracking performance of the Doppler frequency tracking method is free of residual error, can completely eliminate Doppler frequency offset and is not influenced by the Doppler change rate; in the field of USB measurement and control communication, the method has great innovation in the aspect of main carrier tracking, and accords with the development direction of the technology in the field of USB measurement and control communication.
Claims (1)
1. The full digital main carrier tracking method based on Doppler frequency cancellation is characterized by sequentially comprising the following steps of:
step (1): the unified S-band USB measurement and control band-pass analog signal with Doppler frequency difference received by the receiver is converted into a digital signal through an analog-to-digital converter;
step (2): the USB measurement and control band-pass digital signal with the Doppler frequency difference obtained in the step (1) passes through an orthogonal down converter to obtain a complex baseband signal with the Doppler frequency difference, and the real part and the imaginary part of the complex baseband signal are respectively represented by I1、Q1Two paths of data are represented;
and (3): and (3) enabling the baseband complex signal with the Doppler frequency difference obtained in the step (2) to pass through a main carrier capturing device, and eliminating most of the Doppler frequency difference according to the following steps:
step (3.1): the complex baseband signal I in the step (2) is processed1、Q1Converting the complex number into a complex number by using a real number/complex number converter, performing N-point fast Fourier transform and taking an absolute value;
step (3.2): carrying out correlation operation on the amplitude spectrum obtained after the fast Fourier transform in the step (3.1) and a pre-stored preset spectrum template, and searching a correlation peak in a set maximum Doppler range, wherein the frequency position corresponding to the correlation peak is the position of the main carrier in the frequency domain; the preset spectrum template is an amplitude spectrum of a single pulse adopted by a known transmitter, the correlation operation refers to the operation of multiplying and summing sampling points at corresponding positions of two discrete signals with different relative delays, and the maximum Doppler range is determined by the radial velocity of space flight and is usually +/-300 kHz;
step (3.3): and (3) controlling the frequencies of the in-phase oscillation signal and the orthogonal oscillation signal output by the numerically controlled oscillator by using the frequency spectrum position information of the main carrier wave captured in the step (3.2): if the position of the main carrier in the frequency domain deviates from zero frequency by a distance d (hz), the frequency of the two oscillation signals is K × d (hz), where K is the modulation sensitivity of the numerically controlled oscillator, and is usually 1; two paths of oscillation signals output by the controlled oscillator are converted into complex oscillation signals through a real number/complex number converter;
step (3.4): combining the complex oscillating signal obtained in step (3.3) with the input signal I1、Q1Complex baseband signals obtained by real/complex conversion of two data signals are subjected to complex multiplication in a multiplier to eliminate large Doppler frequency difference and the result is converted into two real numbers I of complex signals by a complex/real converter2、Q2Outputting; wherein, the large Doppler frequency difference generally refers to the condition that the maximum residual frequency offset after the frequency difference is eliminated is less than 16 kHz;
and (4): passing the complex signal obtained in step (3) through a spectrum symmetry signal formerTwo paths of complex signals X with frequency spectrums which are symmetrical left and right about zero frequency are obtained according to the following steps1And X2：
Step (4.1): the real part and imaginary part of the input which is removed most of the Doppler frequency difference are respectively I2And Q2To obtain a complex signal X1；
Step (4.2): input signal Q2Multiplied by-1 as imaginary component, input signal I2As a real part, the combiner outputs a complex signal:
wherein, <math><mrow>
<msub>
<mi>X</mi>
<mn>1</mn>
</msub>
<mo>=</mo>
<msub>
<mi>I</mi>
<mn>2</mn>
</msub>
<mo>+</mo>
<msub>
<mi>Q</mi>
<mn>2</mn>
</msub>
<mo>=</mo>
<mi>cos</mi>
<mrow>
<mo>(</mo>
<msub>
<mi>ω</mi>
<mi>ds</mi>
</msub>
<mi>T</mi>
<mo>+</mo>
<munderover>
<mi>Σ</mi>
<mrow>
<mi>n</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>m</mi>
</munderover>
<msub>
<mi>Ψ</mi>
<mi>n</mi>
</msub>
<mo>)</mo>
</mrow>
<mo>+</mo>
<mi>i</mi>
<mi>sin</mi>
<mrow>
<mo>(</mo>
<msub>
<mi>ω</mi>
<mi>ds</mi>
</msub>
<mi>T</mi>
<mo>+</mo>
<munderover>
<mi>Σ</mi>
<mrow>
<mi>n</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>m</mi>
</munderover>
<msub>
<mi>Ψ</mi>
<mi>n</mi>
</msub>
<mo>)</mo>
</mrow>
<mo>=</mo>
<msup>
<mi>e</mi>
<mrow>
<mi>i</mi>
<mrow>
<mo>(</mo>
<msub>
<mi>ω</mi>
<mi>ds</mi>
</msub>
<mi>T</mi>
<mo>+</mo>
<munderover>
<mi>Σ</mi>
<mrow>
<mi>n</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>m</mi>
</munderover>
<msub>
<mi>Ψ</mi>
<mi>n</mi>
</msub>
<mo>)</mo>
</mrow>
</mrow>
</msup>
</mrow></math>
wherein, ω isdsTo remove most of the remaining frequency difference after the doppler frequency difference,
m is the number of subcarriers in the USB system,
Ψnthe signal is modulated for the nth subcarrier and,
t is discrete sampling time;
and (5): the complex signal X with symmetrical frequency spectrum obtained in the step (4)1And X2After Doppler frequency cancellation pretreatment, the following signals are output in two paths according to the following steps: complex baseband signal Y with pre-eliminated residual Doppler frequency difference1And a Doppler frequency difference complex signal Y2：
Step (5.1): input complex signal X2Filtered by a finite impulse response FIR low-pass filter, the complex signal Y only containing Doppler frequency difference information is output2: the <math><mrow>
<msub>
<mi>Y</mi>
<mn>2</mn>
</msub>
<mo>=</mo>
<msup>
<mi>e</mi>
<mrow>
<mo>-</mo>
<mi>i</mi>
<mrow>
<mo>(</mo>
<msub>
<mi>ω</mi>
<mi>ds</mi>
</msub>
<msup>
<mi>T</mi>
<mo>′</mo>
</msup>
<mo>)</mo>
</mrow>
</mrow>
</msup>
<mo>,</mo>
</mrow></math> The bandwidth of the FIR low-pass filter is equal to or more than the maximum residual frequency offset after the elimination of the large Doppler frequency offset, and the bandwidth is simultaneously less than or equal to the modulation frequency of a subcarrier closest to the main carrier in the frequency spectrum of the USB measurement and control signal;
step (5.2): input complex signal X1And (3) delaying by a delayer, wherein the delay is equal to the delay of the FIR low-pass filter in the step (5.1):
and (6): using a Doppler frequency canceller to output the complex baseband signal Y output in step (5)1And negative doppler difference complex signal Y2Multiplying the complex number to eliminate the residual Doppler frequency difference and output signal Z,
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007101799740A CN101179545B (en) | 2007-12-20 | 2007-12-20 | Doppler frequency cancellation based full digital main carrier tracking method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007101799740A CN101179545B (en) | 2007-12-20 | 2007-12-20 | Doppler frequency cancellation based full digital main carrier tracking method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101179545A true CN101179545A (en) | 2008-05-14 |
| CN101179545B CN101179545B (en) | 2010-06-09 |
Family
ID=39405633
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2007101799740A Expired - Fee Related CN101179545B (en) | 2007-12-20 | 2007-12-20 | Doppler frequency cancellation based full digital main carrier tracking method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101179545B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102316058A (en) * | 2011-03-18 | 2012-01-11 | 中国科学院上海微系统与信息技术研究所 | Coherent demodulation device of non-geostationary orbit satellite DQPSK (Differential Quadrature Phase Shift Keying) communication |
| WO2012048573A1 (en) * | 2010-10-16 | 2012-04-19 | 中兴通讯股份有限公司 | Method, device and system for modulating complex carriers |
| CN101742615B (en) * | 2008-11-27 | 2012-10-10 | 中兴通讯股份有限公司 | Large bandwidth multi-carrier system and broadcast information updating method thereof |
| CN105704081A (en) * | 2016-01-12 | 2016-06-22 | 中国电子科技集团公司第十研究所 | Optimization and demodulation method of multiple offset carrier wave amplitude modulation signals |
| CN107753058A (en) * | 2017-11-22 | 2018-03-06 | 深圳中科乐普医疗技术有限公司 | A kind of shearing wave dynamic filter method |
| CN112230212A (en) * | 2020-09-28 | 2021-01-15 | 北京环境特性研究所 | Radar ranging signal processing method and device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1309192C (en) * | 2002-08-27 | 2007-04-04 | 山东大学 | Method for tracing carrier frequency of orthogonal frequency division multiplexing system in multipath fading channel |
| CN1333533C (en) * | 2005-05-16 | 2007-08-22 | 北京北方烽火科技有限公司 | Method of frequency compensation for Direct Sequence Spread Spectrum (DSSS) mobile communication system |
| CN1968236B (en) * | 2005-11-15 | 2011-04-27 | 中国科学技术大学 | Doppler frequency offset estimation method |
-
2007
- 2007-12-20 CN CN2007101799740A patent/CN101179545B/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101742615B (en) * | 2008-11-27 | 2012-10-10 | 中兴通讯股份有限公司 | Large bandwidth multi-carrier system and broadcast information updating method thereof |
| WO2012048573A1 (en) * | 2010-10-16 | 2012-04-19 | 中兴通讯股份有限公司 | Method, device and system for modulating complex carriers |
| US8989310B2 (en) | 2010-10-16 | 2015-03-24 | Zte Corporation | Method, device and system for complex carrier modulation |
| CN102316058A (en) * | 2011-03-18 | 2012-01-11 | 中国科学院上海微系统与信息技术研究所 | Coherent demodulation device of non-geostationary orbit satellite DQPSK (Differential Quadrature Phase Shift Keying) communication |
| CN102316058B (en) * | 2011-03-18 | 2014-04-09 | 中国科学院上海微系统与信息技术研究所 | Coherent demodulation device of non-geostationary orbit satellite DQPSK (Differential Quadrature Phase Shift Keying) communication |
| CN105704081A (en) * | 2016-01-12 | 2016-06-22 | 中国电子科技集团公司第十研究所 | Optimization and demodulation method of multiple offset carrier wave amplitude modulation signals |
| CN105704081B (en) * | 2016-01-12 | 2018-10-23 | 中国电子科技集团公司第十研究所 | Multiple offset carrier amplitude-modulated signals preferably and demodulation method |
| CN107753058A (en) * | 2017-11-22 | 2018-03-06 | 深圳中科乐普医疗技术有限公司 | A kind of shearing wave dynamic filter method |
| CN112230212A (en) * | 2020-09-28 | 2021-01-15 | 北京环境特性研究所 | Radar ranging signal processing method and device |
| CN112230212B (en) * | 2020-09-28 | 2023-06-16 | 北京环境特性研究所 | Radar ranging signal processing method and device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101179545B (en) | 2010-06-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102025388B (en) | Emulational USB intermediate frequency responser used for satellite test and control | |
| CN106165366B (en) | Frequency and phase offset compensation are carried out to modulated signal using symbol timing recovery | |
| CN101179545B (en) | Doppler frequency cancellation based full digital main carrier tracking method | |
| CN108092929B (en) | Synchronization method for terahertz communication | |
| CN102571137B (en) | Fully-digital direct sequence spread spectrum communication system and rapid pseudo code capturing method thereof | |
| JPH02105746A (en) | Differental phase transition keying modulator | |
| CN107682293B (en) | Phase modulation signal frequency offset estimation and tracking method based on nonlinear transformation | |
| CN108183877B (en) | Multi-tone frequency modulation signal demodulation method based on FPGA | |
| CN110300079B (en) | MSK signal coherent demodulation method and system | |
| CN109039471B (en) | Digital-analog hybrid demodulation method applied to high-speed laser communication | |
| CN105093243A (en) | GNSS carrier loop circuit tracking method based on stochastic resonance algorithm | |
| AU2002332824B2 (en) | Reception of a plurality of phase-modulated signals | |
| CN112731475A (en) | GNSS occultation double-branch signal open-loop tracking method | |
| CN106656400A (en) | Accurate frequency difference fast acquisition method in time delay jitter condition of PCMA system | |
| CN102368690A (en) | Micro-nano satellite measurement and control digit midfrequency and baseband processing method and apparatus thereof | |
| JP7004618B2 (en) | Frequency estimator and tracking receiver | |
| CN106341123B (en) | A kind of filtering method and device of single tone jamming | |
| CN113381778A (en) | Polarization diversity signal receiving method based on FPGA | |
| CN107733824A (en) | A kind of carrier synchronization method based on AFC loops | |
| CN104678388B (en) | GNSS-R orthogonalization staggered processing device for improving height measurement precision | |
| Shachi et al. | Coherent BPSK demodulator using Costas loop and early-late gate synchronizer | |
| CN115189991A (en) | Device and method for phase modulation synchronous demodulation | |
| CN110716214A (en) | Signal processing method and device | |
| Uma Devi et al. | Carrier recovery and clock recovery for QPSK demodulation | |
| GB2382282A (en) | A digital demodulator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100609 Termination date: 20161220 |