WO2022036489A1 - 一种卫星激光宽带解调方法与装置 - Google Patents

一种卫星激光宽带解调方法与装置 Download PDF

Info

Publication number
WO2022036489A1
WO2022036489A1 PCT/CN2020/109464 CN2020109464W WO2022036489A1 WO 2022036489 A1 WO2022036489 A1 WO 2022036489A1 CN 2020109464 W CN2020109464 W CN 2020109464W WO 2022036489 A1 WO2022036489 A1 WO 2022036489A1
Authority
WO
WIPO (PCT)
Prior art keywords
carrier
frequency
capture
signal
module
Prior art date
Application number
PCT/CN2020/109464
Other languages
English (en)
French (fr)
Inventor
张传胜
龚高茂
赵海军
何峰
吕游
Original Assignee
湖南迈克森伟电子科技有限公司
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 湖南迈克森伟电子科技有限公司 filed Critical 湖南迈克森伟电子科技有限公司
Priority to PCT/CN2020/109464 priority Critical patent/WO2022036489A1/zh
Priority to CN202080077073.4A priority patent/CN114667717B/zh
Priority to US17/777,780 priority patent/US20220416896A1/en
Priority to EP20949702.3A priority patent/EP4024798A4/en
Publication of WO2022036489A1 publication Critical patent/WO2022036489A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
    • H04B10/118—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum specially adapted for satellite communication
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/29—Repeaters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/61—Coherent receivers
    • H04B10/616—Details of the electronic signal processing in coherent optical receivers
    • H04B10/6164—Estimation or correction of the frequency offset between the received optical signal and the optical local oscillator
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/61—Coherent receivers
    • H04B10/616—Details of the electronic signal processing in coherent optical receivers
    • H04B10/6165—Estimation of the phase of the received optical signal, phase error estimation or phase error correction
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0044—Control loops for carrier regulation
    • H04L2027/0053—Closed loops
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/38—Demodulator circuits; Receiver circuits
    • H04L27/3809—Amplitude regulation arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/38—Demodulator circuits; Receiver circuits
    • H04L27/3845—Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier
    • H04L27/3854—Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier using a non - coherent carrier, including systems with baseband correction for phase or frequency offset
    • H04L27/3863—Compensation for quadrature error in the received signal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the invention relates to the technical field of laser communication, and more particularly, to a satellite laser broadband demodulation method and device.
  • the carrier Doppler received by the receiver is as high as ⁇ 5 GHz, which exceeds the frequency offset range that can be captured by conventional receivers, and the digital frequency of the receiver itself is coherently demodulated.
  • the compensation range is limited, and it cannot process such a high Doppler carrier range, which does not meet the requirements of large-capacity and high-speed satellite laser communication, and will lead to problems such as low carrier acquisition accuracy and low communication quality.
  • the object of the present invention is to overcome the deficiencies of the prior art, and to provide a satellite laser broadband demodulation method and device,
  • a satellite laser broadband demodulation method comprising the following steps:
  • an accurate carrier frequency is obtained through an accurate frequency acquisition method, so that the residual carrier enters the fast acquisition band of the carrier tracking phase-locked loop.
  • a signal preprocessing step S1 is included, and in step S1, the preprocessing including the residual Doppler carrier signal is completed, including four links of DC removal, IQ amplitude equalization, AGC gain control and matched filtering, wherein The DC removal link is used to remove the DC component in the signal, so as to completely eliminate the carrier component; IQ amplitude equalization compensates the imbalance of the amplitude and phase of the I and Q channels; the signal amplitude is adjusted to be suitable for processing through AGC gain control; matched filtering Then the noise signal is filtered out.
  • step S23 including carrier tracking step S3, in step S3, the carrier loop performs real-time co-frequency and in-phase tracking on the input carrier, and performs co-frequency and in-phase tracking on the position, and accurately aligns the middle position of the position. Timed extraction.
  • step S3 an early-late gate phase-locked loop is used to track the bit loop.
  • step S4 is performed after step S3, and the step S4 includes phase blurring, differential decoding, frame synchronization, state control, descrambling and decoding links, for realizing the recovery of the data after the bit synchronization in step S3 deal with.
  • a satellite laser broadband demodulation device comprising a signal preprocessing module, a signal capturing module and a signal tracking module; the signal first passes through the signal preprocessing module, and the signal preprocessing module is used for de-DC, IQ amplitude equalization, After the AGC gain control and matched filtering are sent to the signal tracking module, the signals before and after matched filtering are sent to the capture module for coarse capture and fine capture of the carrier frequency; the capture results of the coarse capture and fine capture are respectively used for frequency locking The phase-locked loop in the loop and signal tracking module; the signal tracking module performs soft decision after carrier synchronization and symbol/bit synchronization, and outputs data in parallel bus mode.
  • the signal capture module includes a rough carrier capture module, the carrier rough capture module, the capture result carrier accuracy ⁇ 1MHz, and the output result of the rough capture module is used for the frequency discrimination result of the frequency-locked loop and as a fine capture. Input control of the module.
  • the signal capture module includes a carrier wave fine capture module, the carrier wave fine capture module is used to obtain a carrier frequency with higher frequency accuracy than the rough capture result, and the output frequency control word is used for the phase locked loop of the tracking module, and the carrier wave
  • the integration in the fine capture module is used to reduce the sampling rate and to achieve filtering, suppressing out-of-band noise near the carrier frequency band to improve the signal-to-noise ratio.
  • the carrier loop performs real-time co-frequency and in-phase tracking on the input carrier, co-frequency and co-phase tracking on the bit, and accurately aligns the middle position of the bit for timing extraction.
  • an early-late gate phase-locked loop is used to track the bit loop.
  • the present invention can achieve ultra-high bandwidth/high-speed signal equalization, and quickly complete carrier acquisition, tracking, and information data demodulation recovery from modulated signals with high dynamic range.
  • the residual carrier is firstly set to the carrier acquisition range of the receiver (scanning and intercepting), and then the residual carrier is pulled to the MHz level (frequency locking pulling) by adjusting the frequency of the local oscillator laser.
  • the accurate carrier frequency is obtained by the frequency acquisition method, so that the residual carrier enters the fast acquisition band of the carrier tracking phase-locked loop. After the carrier acquisition is completed, the carrier tracking and data recovery processing are performed.
  • the present invention uses coarse acquisition (frequency pulling, elimination of high Doppler frequency shift of the carrier) to pull the residual carrier to the MHz level, and through the combination of precise frequency acquisition, accurate frequency acquisition methods are used to obtain accurate carrier waves frequency.
  • the present invention provides a satellite laser broadband demodulation and recovery device, which can complete ultra-high bandwidth/high-speed signal equalization, and quickly complete carrier acquisition, tracking, and information data demodulation recovery from modulated signals with high dynamic range.
  • the residual carrier is firstly set to the carrier acquisition range of the receiver (scanning and intercepting), and then the residual carrier is pulled to the MHz level (frequency locking pulling) by adjusting the frequency of the local oscillator laser.
  • the accurate carrier frequency is obtained by the frequency acquisition method, so that the residual carrier enters the fast acquisition band of the carrier tracking phase-locked loop. After the carrier acquisition is completed, carrier tracking and data recovery processing are performed.
  • FIG. 1 is a schematic structural block diagram of a carrier tracking loop of the present invention
  • Fig. 2 is the running flow schematic diagram of the tracking module of the present invention
  • FIG. 3 is a schematic diagram of a signal processing flow diagram of the present invention.
  • Fig. 4 is a signal processing structure diagram
  • Fig. 5 is the module software structure diagram
  • Fig. 6 is the working schematic diagram of the rough capture module
  • Fig. 7 is a signal state simulation diagram
  • Figure 8 is a simulation diagram of the rough capture result (the ordinate does not represent an absolute value);
  • Fig. 9 is a simulation diagram of the fine capture result (the ordinate does not represent an absolute value).
  • Figure 10 is a signal state simulation diagram
  • Figure 11 is a simulation diagram of the rough capture result (the ordinate does not represent an absolute value);
  • Figure 12 is a simulation diagram of the fine capture result (the ordinate does not represent an absolute value).
  • first, second and the like appear in this application to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a “first” element discussed below could also be termed a “second” element without departing from the context of the present invention. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.
  • a satellite laser broadband demodulation method includes:
  • an accurate carrier frequency is obtained through an accurate frequency acquisition method, so that the residual carrier enters the fast acquisition band of the carrier tracking phase-locked loop.
  • a signal preprocessing step S1 is included, and the preprocessing including the residual Doppler carrier signal is completed in step S1, including four links of DC removal, IQ amplitude equalization, AGC gain control, and matched filtering, wherein
  • the purpose of removing the DC link is to remove the DC component in the signal in order to completely eliminate the carrier component;
  • IQ amplitude equalization compensates the imbalance of the amplitude and phase of the I and Q channels; the signal amplitude is adjusted to be suitable for processing through AGC gain control; matched filtering Then the noise signal is filtered out.
  • step S23 including carrier tracking step S3, in step S3, the carrier loop performs real-time co-frequency and in-phase tracking on the input carrier, and performs co-frequency and in-phase tracking on the position, and accurately aligns the middle position of the position. Timed extraction.
  • step S3 an early-late gate phase-locked loop is used to track the bit loop.
  • step S4 is performed after step S3, including phase blurring processing, differential decoding, frame synchronization, state control, descrambling and decoding, for realizing the recovery processing of the data after bit synchronization in step 3.
  • a satellite laser broadband demodulation device includes a signal preprocessing module, a signal capturing module and a signal tracking module; the signal first passes through the signal preprocessing module, and the signal preprocessing module is used for DC removal, IQ amplitude equalization, AGC gain control and After matched filtering, it is sent to the signal tracking module. At the same time, the signals before and after matched filtering are sent to the capture module for coarse capture and fine capture of the carrier frequency. The two capture results are used for the frequency-locked loop and the phase-locked loop in the signal tracking module respectively. Use; the signal tracking module performs soft decision after carrier synchronization and symbol/bit synchronization, and outputs data in parallel bus mode.
  • the signal acquisition module includes a rough carrier acquisition module, the carrier rough acquisition module, the carrier accuracy of the acquisition result is less than or equal to 1MHz, and the output result of the rough acquisition module includes two purposes: one is for the frequency-locked loop.
  • the frequency discrimination result is used as the input control of the precise capture module.
  • the signal capture module includes a carrier wave fine capture module
  • the carrier wave fine capture module is used to obtain a carrier frequency with higher frequency accuracy than the rough capture result
  • the output frequency control word is used for the phase locked loop of the tracking module
  • the carrier wave The integration in the fine capture module has two purposes: one is to reduce the sampling rate, and the other is to achieve filtering, suppressing out-of-band noise near the carrier frequency band, and improving the signal-to-noise ratio.
  • the carrier loop performs real-time co-frequency and co-phase tracking on the input carrier, co-frequency and co-phase tracking on the bit, and accurately aligns the middle position of the bit for timing extraction.
  • an early-late gate phase-locked loop is used to track the bit loop.
  • a satellite laser broadband demodulation method comprising the following steps:
  • Step 1 signal preprocessing, complete the preprocessing including residual Doppler carrier signal, including four links: DC removal, IQ amplitude equalization, AGC gain control, and matched filtering.
  • the purpose of the DC removal link is to remove the DC component in the signal.
  • IQ amplitude equalization compensates the unbalance of the amplitude and phase of I and Q channels, adjusts the signal amplitude to be suitable for processing through AGC gain control, and further filters out the noise signal by matched filtering.
  • Step 2 carrier acquisition, is implemented in three steps: scan acquisition, frequency-locked traction, and frequency fine-grained acquisition. It mainly completes the capture of the carrier frequency in the signal, which is divided into coarse capture and fine capture. The carrier frequency result of the precision capture) is used for the initial frequency input of the carrier phase-locked loop.
  • Step 3 carrier tracking, after the acquisition is completed, the carrier frequency is roughly estimated, but there is no phase information.
  • the carrier loop In order to completely remove the carrier in the digital IF input signal and down-convert it from the IF to the baseband, it is necessary to make the locally recovered carrier and the input carrier in the same frequency and phase. Then the carrier loop is required to track the input carrier in real time with the same frequency and phase.
  • the carrier loop In order to recover the bit stream, it is necessary to track the bits in the same frequency and phase, accurately align the middle position of the bits, and perform timing extraction.
  • the present invention uses an early-late gate (lead-lag) phase-locked loop to track the bit loop.
  • Step 4 Signal recovery, including phase blur processing, differential decoding, frame synchronization, state control, descrambling and decoding links, to achieve recovery processing of data after bit synchronization.
  • the invention also provides a satellite laser broadband demodulation and recovery device, which includes three major modules: signal preprocessing, signal capture, and signal tracking.
  • the working clock frequency is fixed at 156.25MHz of the signal accompanying clock (the sampling center frequency of the ADC is fixed at 5GHz).
  • the signal is first sent to the signal tracking module after signal preprocessing (DC removal, IQ amplitude equalization, AGC gain control, matched filtering), and at the same time, the signals before and after matched filtering are sent to the capture module for coarse capture and fine capture of the carrier frequency.
  • the two capture results are respectively used in the frequency-locked loop and the phase-locked loop in the signal tracking module.
  • the signal tracking module completes carrier synchronization (carrier phase-locked loop) and symbol/bit synchronization (symbol/bit phase-locked loop), it performs soft decision and outputs data in parallel bus mode.
  • Coarse capture of carrier The frequency range of the carrier that the module needs to capture is ⁇ 500MHz (the Doppler maximum can reach ⁇ 5GHz during laser reception, and when it exceeds ⁇ 500MHz, it is necessary to control the laser local oscillator scanning according to the coarse capture amplitude information, so that the receiving
  • the residual carrier is adjusted within the range of ⁇ 500MHz), and the carrier accuracy of the capture result needs to be ⁇ 1MHz.
  • the input of the coarse carrier capture is the data before digital matched filtering, because when the residual carrier is large, the signal spectrum will exceed the bandwidth of the filter, and the signal energy will be partially filtered, which will affect the capture result.
  • the output result of the coarse capture module has two purposes: one is for the frequency discrimination result of the frequency-locked loop; The pre-compensated carrier frequency of the DDC).
  • Accurate carrier capture Obtain a carrier frequency with higher frequency accuracy than the coarse capture result, and output the frequency control word for the phase-locked loop of the tracking module.
  • the carrier frequency range that this module needs to capture is ⁇ 20MHz, and the carrier accuracy of the capture result needs to be ⁇ 200kHz.
  • the input of carrier precision capture is digital matched filtered data (that is, the same input data used by the tracking module).
  • the integration (segment integration) in the carrier fine capture module has two functions: one is to reduce the sampling rate, and the other is to realize the filtering effect, suppress the out-of-band noise near the carrier frequency band, and improve the signal-to-noise ratio.
  • the precise acquisition module is implemented by integrating first and then FFT. Even under the maximum Doppler dynamic effect, the acquisition accuracy is 81.37kHz.
  • Carrier tracking loop mainly completes signal carrier, bit (symbol) tracking (synchronization), symbol decision (soft decision), and signal-to-noise ratio estimation.
  • the tracking loop is an important part of the receiver, mainly including: carrier tracking loop and symbol loop. After the acquisition is completed, a rough estimate of the carrier frequency is made without phase information. In order to remove the carrier in the digital IF input signal and down-convert it from the IF to the baseband, it is necessary to make the locally recovered carrier and the input carrier have the same frequency and phase. Then the carrier loop is required to track the input carrier in real time with the same frequency and phase.
  • the present invention uses the Costas loop to implement carrier tracking. In order to recover the bit stream, it is necessary to track the bits in the same frequency and phase, accurately align the middle position of the bits, perform timing extraction, and select an early-late gate (lead-lag) phase-locked loop to track the bit loop.
  • the tracking module needs to use 2 clocks, one is the demodulation data domain clock i_clk, and the other is the working clock i_clk_dds of the bit-synchronized NCO.
  • i_clk_dds arrives before i_clk, and its reset release (i_rst_dds) also precedes i_rst.
  • the bit NCO of this tracking module works first, and then after i_clk is valid and i_rst is reset and released, the rest of the logic inside the tracking module enters the initial state, and after the fine capture carrier result is input, the carrier Synchronization and bit synchronization start working at the same time.
  • This tracking module is internally set up with automatic timing detection for carrier synchronization. Once it is detected that the carrier synchronization is out of lock, all modules except the bit NCO and the detection module when out of lock are automatically reset, so that they basically enter the reset initial state and wait for the next time. After the fine capture is completed, the synchronization of the two loops is restarted.
  • Signal processing includes several major parts: signal preprocessing, signal acquisition, signal tracking, data recovery, channel reception, and interface processing. The detailed processing process is shown in Figure 3.
  • the demodulation module mainly completes the demodulation of the signal and outputs soft decision data.
  • the content implemented by this demodulation module is carrier extraction, timing extraction, extraction judgment, and parallel-serial conversion in the above figure.
  • the demodulation process is implemented by software and hardware, because the timing extraction required for symbol synchronization needs to be realized by adjusting the frequency and phase of the sampling clock of the ADC.
  • the digital demodulator can be divided into 4 main processes by function: gain control (AGC), equalization compensation (IQ amplitude compensation, phase compensation), carrier synchronization (including carrier acquisition, carrier tracking), bit synchronization and symbol decision (constellation diagram). mapping).
  • the demodulator has three main loops: gain control loop (AGC), carrier loop (PLL), and bit synchronization loop (based on PLL technology).
  • AGC gain control loop
  • PLL carrier loop
  • bit synchronization loop based on PLL technology.
  • the three loops can work independently and in parallel.
  • Digital AGC is used in digital signal processing.
  • the controller module is responsible for the frequency discrimination calculation in the frequency-locked loop.
  • the software structure of the demodulation module consists of three modules: signal preprocessing, signal capture and signal tracking.
  • the working clock frequency is fixed at 156.25MHz of the signal follower clock, and the sampling frequency of the ADC is dynamically adjustable around 5GHz.
  • the signal is first sent to the signal tracking module after signal preprocessing (DC removal, IQ amplitude equalization, AGC gain control, matched filtering), and at the same time, the signals before and after matched filtering are sent to the capture module for coarse capture and fine capture of the carrier frequency.
  • the two capture results are respectively used in the frequency-locked loop and the phase-locked loop in the signal tracking module.
  • the signal tracking module completes carrier synchronization (carrier phase-locked loop) and symbol/bit synchronization (symbol/bit phase-locked loop), it performs soft decision and outputs data in parallel bus mode.
  • the carrier Doppler obtained by the receiver is as high as ⁇ 5GHz, which exceeds the frequency range that the conventional receiver can capture, and the receiver’s own digital frequency during coherent demodulation
  • the compensation range is limited, so it is necessary to first set the residual carrier to the carrier acquisition range of the receiver (scanning and interception), and then adjust the frequency of the local oscillator laser to pull the residual carrier to the MHz level (frequency locking pull), and finally pass the precise
  • the accurate carrier frequency is obtained by the frequency acquisition method, so that the residual carrier enters the fast acquisition band of the carrier tracking phase-locked loop.
  • Coarse acquisition frequency pulling, elimination of high Doppler frequency shift of the carrier
  • the precise carrier frequency is obtained by precise frequency acquisition.
  • (I+jQ) 2 expands to I2-Q2+2IQJ;
  • the integral value is a fixed value, which can be set as A, then:
  • the capture module completes the rough capture of the carrier wave.
  • the frequency range of the carrier wave that this module needs to capture is ⁇ 500MHz (the Doppler maximum can reach ⁇ 5GHz during laser reception, and when it exceeds ⁇ 500MHz, it is necessary to use the coarse capture amplitude information to control the laser itself vibrating and scanning, so that the received residual carrier is adjusted within the range of ⁇ 500MHz), and the carrier accuracy of the capture result needs to be ⁇ 1MHz.
  • the input of the rough carrier capture must be the data before digital matched filtering, because when the residual carrier is large, the signal spectrum will exceed the bandwidth of the filter, and the signal energy will be partially filtered, which will affect the capture result.
  • the output result of the coarse capture module has two purposes: one is for the frequency discrimination result of the frequency-locked loop; The pre-compensated carrier frequency of the DDC).
  • the coarse capture module is used as the frequency discrimination part of the frequency-locked loop.
  • the schematic diagram of the whole frequency-locked loop is as follows (the green part is the part of the carrier coarse capture module):
  • the processing delay (Td) of the capture module consists of two parts. One is the input time T1 of the signal itself (serial input time). The second is the time delay (T2) of FFT processing.
  • T1 the input time
  • T2 the time delay
  • the longer the input data time will cause the FFT peak to be blurred, and the longer the processing time will cause the FFT output frequency to not represent the real frequency value.
  • the number of FFT design points in the coarse acquisition module is 4096 points, and the design parameters determined from this are shown in Figure 6: Even under the maximum Doppler dynamic effect, the acquisition accuracy is 611.78kHz.
  • the fine capture module the module completes the fine capture of the carrier, obtains the carrier frequency with higher frequency accuracy than the coarse capture result, and outputs the frequency control signal to track the use of the phase-locked loop of the module.
  • the carrier frequency range that this module needs to capture is ⁇ 20MHz, and the carrier accuracy of the capture result is ⁇ 200kHz.
  • the input of carrier precision capture is digital matched filtered data (that is, the same input data used by the tracking module).
  • the integration (segment integration) in the carrier fine capture module has two functions: one is to reduce the sampling rate; Even at maximum Doppler dynamics, the capture accuracy is 81.37kHz.
  • the final captured carrier frequency is -499.115MHz, which is only 8kHz away from the set value.
  • the generated BPSK signal has no phase noise, no Doppler, and a signal-to-noise ratio of 10dB.
  • the final captured carrier frequency is -499.115MHz, which is only 8kHz away from the set value.
  • the signal tracking module mainly completes signal carrier, bit (symbol) tracking (synchronization), symbol decision (soft decision), and signal-to-noise ratio estimation.
  • the tracking loop is an important part of the receiver, mainly including: carrier tracking loop and symbol loop. After the acquisition is completed, a rough estimate of the carrier frequency is made without phase information. In order to completely remove the carrier in the digital IF input signal and down-convert it from the IF to the baseband, it is necessary to make the locally recovered carrier and the input carrier in the same frequency and phase. Then the carrier loop is required to track the input carrier in real time with the same frequency and phase.
  • the invention adopts Costas loop to realize carrier tracking. In order to recover the bit stream, it is necessary to track the bits in the same frequency and phase, accurately align the middle position of the bits, and perform timing extraction. This scheme uses the early-late gate (lead-lag) phase-locked loop to track the bit loop.
  • the block diagram of the tracking loop of the high bit rate xPSK system is shown in Figure 1.
  • Pre-integration in carrier-synchronized phase-locked loop In FPGA implementation, due to the constraint of calculation delay, the number of integration points is used to the power of 2 n , and the FPGA averages the integrated data.
  • phase detectors used in the two loops are as follows.
  • I p (n) and Q p (n) are the accumulated sums (values after pre-integration) of the immediate branches of the I channel and the Q channel at the current moment.
  • Y I (r) and Y Q (r) represent the sampling point values of the r-th symbol I and Q at the decision moment
  • Y I (r-1/2) and Y Q (r-1/2 ) represents the intermediate sample point value between the rth and r-1th symbols.
  • Loop filter the loop filters of the two loops both use a first-order ideal active proportional-integral filter (forming a second-order loop), and the determination of the loop parameters (T, K1, K2) is mainly to First determine the loop bandwidth BL , then obtain the integration time T, and ⁇ n , and then calculate K1 and K2 according to the formula.
  • the selection of loop parameters is mainly based on the dynamic indicators of the signal to be tracked by the loop (input signal phase noise, required fast capture bandwidth, maximum capture scan rate, maximum synchronous scan rate) and phase-locked loop output indicators (loop Signal-to-noise ratio, fast capture time, frequency ramp-up steady-state phase difference) to determine.
  • the processing delay limits the integration time.
  • the processing delay limits the improvement of the loop bandwidth.
  • the phase-locked loop is fully digitally implemented in the FPGA, so the delay of the loop comes from the data calculation delay of the FPGA, and the loop calculation requires 8 clock cycles.
  • the channel-dependent clock output by the ADC is used as the main clock of the phase-locked loop after frequency division.
  • the clock frequency is 156.25MHz (period 6.4ns), so the loop delay is 51.2ns. According to the constraint relationship between the processing delay and the integration time, the integration time must not be lower than this value.
  • the NCO output of the phase-locked loop directly controls the sampling clock of the ADC, so the loop delay is mainly composed of two parts: the FPGA loop calculation and the DAC propagation delay of the NCO.
  • the bit Doppler dynamic during the bit synchronization phase tracking is small (about 1KHz/s), and the static Doppler has pre-compensation, so the loop bandwidth can be as long as KHz level, pre-integration
  • the time can reach about 20us.
  • the FPGA loop calculation delay is 20 clock cycles, and the DAC propagation delay is 4 clock cycles + 21.5ns. Therefore, when the loop clock is 156.25MHz (period 6.4ns) and the DAC conversion rate is 50MHz (20ns), the total loop delay is 229.5ns. Compared with the pre-integration time of 20us, the delay is a small amount, so the influence of the loop delay on the loop performance can be ignored.
  • phase noise of the optical carrier in laser communication restricts the bandwidth of the carrier synchronization loop.
  • the phase noise of the receiving and transmitting lasers is the main factor that determines the selection of phase-locked loop parameters. It is determined that the number of integration points is 16 points (the integration time is 102.40ns), the corresponding update frequency is 9.77MHz, and the loop bandwidth is obtained as 244.14kHz.
  • the precision of code/bit Doppler pre-complementation in laser communication restricts the bandwidth of the bit synchronization loop.
  • the code Doppler bandwidth can reach ⁇ 50kHz under the satellite motion, and the code Doppler rate is 1kHz/s and the code Doppler acceleration is 1kHz/s2 compared with the code Doppler bandwidth to the loop bandwidth. The restrictions are small.
  • the accuracy after Doppler pre-complementation is the fast capture bandwidth that the bit synchronization loop needs to provide, and the comprehensive selection of the bit synchronization bandwidth is 1kHz.
  • the signal-to-noise ratio estimation uses the data before the soft decision of Idata and Qdata output by the symbol/bit loop, and the following calculation can be performed after being rotated into a BPSK constellation; for parallel data, only one of them needs to be taken), the calculation formula is as follows .
  • the output frequency of the bit-synchronized NCO (DDS) is a part of the ADC sampling clock, which in turn is the working clock of the entire demodulator.
  • the internal tracking module runs as follows:
  • the tracking module needs to use 2 clocks, one is the demodulation data domain clock i_clk, and the other is the working clock i_clk_dds of the bit synchronous NCO (DDS).
  • i_clk_dds arrives before i_clk, and its reset release (i_rst_dds) also precedes i_rst.
  • the bit NCO of this tracking module works first, and then after i_clk is valid and i_rst is reset and released, the rest of the logic inside the tracking module enters the initial state, and after the fine capture carrier result is input, the carrier is synchronized. , Bit synchronization starts to work at the same time.
  • This tracking module is internally set up with automatic timing detection for carrier synchronization. Once it detects that the carrier synchronization is out of lock, it automatically resets all modules except the bit NCO and the detection module when it is out of lock, so that it basically enters the reset initial state (except for the bit NCO). The initial phase cannot be recovered, and the initial phase does not affect the bit tracking process), wait for the next fine capture to be completed and restart the synchronization of the carrier loop and the bit loop.
  • the disclosed systems, modules and methods can be implemented in other ways.
  • the apparatus embodiments described above are only illustrative.
  • the division of the units may only be a logical function division.
  • multiple units or components may be Incorporation may either be integrated into another system, or some features may be omitted, or not implemented.
  • the shown or discussed mutual coupling or direct coupling or communication connection can be said to be indirect coupling or communication connection of devices or units through some interfaces, which can be in electrical, mechanical or other forms.
  • the units described by the discrete components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.
  • the functions, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer-readable storage medium.
  • the technical solution of the present invention can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution.
  • the computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention.
  • the aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program codes .
  • the storage medium may be a magnetic disk, an optical disk, a ROM, a RAM, and the like.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Astronomy & Astrophysics (AREA)
  • General Physics & Mathematics (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

本发明公开了一种卫星激光宽带解调方法与装置，包括步骤：先将残留载波设置到接收机的载波捕获范围，再通过对本振激光器的频率调整来将残留载波牵引至MHz级别，最后再通过精准的频率捕获手段得到精确的载波频率，从而使得残留载波进入载波跟踪锁相环的快捕带内。完成载波捕获后，再进行载波跟踪以及数据恢复处理。本发明能够完成超高带宽/超高速率的信号均衡，从高动态范围的调制信号中快速完成载波捕获、跟踪以及信息数据解调恢复。

Description

一种卫星激光宽带解调方法与装置 技术领域
本发明涉及激光通信技术领域，更为具体地，涉及一种卫星激光宽带解调方法与装置。
背景技术
目前，由于卫星运动和激光器本身的频率特性，接收机收到的载波多普勒高达±5GHz，此范围超过了常规接收机能够捕获的频偏范围，且接收机相干解调时本身的数字频率补偿范围有限，无法对如此高的多普勒载波范围进行处理，不符合大容量、高速率的卫星激光通信要求，而且会导致载波捕获精度低、通信质量不高等问题。
发明内容
本发明的目的在于克服现有技术的不足，提供一种卫星激光宽带解调方法与装置，
本发明的目的是通过以下技术方案来实现的：
一种卫星激光宽带解调方法，包括以下步骤：
S21，扫描截获，先将残留载波设置到接收机的载波捕获范围；
S22，锁频牵引，再通过对本振激光器的频率调整来将残留载波牵引至MHz级别；
S23，再通过精准的频率捕获手段得到精确的载波频率，从而使得残留载波进入载波跟踪锁相环的快捕带内。
进一步的，在步骤S21前，包括信号预处理步骤S1，在步骤S1中完成包含残留多普勒载波信号的预处理，包括去直流、IQ幅度均衡、AGC增益控制以及匹配滤波四个环节，其中所述去直流环节用于去除信号中的直流成分，以便完全消除载波分量；IQ幅度均衡补偿I、Q路幅度相位的不均衡；通过AGC增益控制将信号幅值调整到适于处理；匹配滤波则对噪声信号进行滤除。
进一步的，在步骤S23之后，包括载波跟踪步骤S3，在步骤S3中载波环路对输入载波进行实时同频同相的跟踪，对位进行同频同相的跟踪，精准对准位的中间位置，进行定时提取。
进一步的，在步骤S3中，采用早迟门锁相环进行位环的跟踪。
进一步的，在步骤S3后执行步骤S4，所述步骤S4包括相位模糊处理、差分译码、帧同步、状态控制、解扰及译码环节，用于实现对步骤S3中位同步后数据的恢复处理。
一种卫星激光宽带解调装置，包括信号预处理模块、信号捕获模块和信号跟踪模块；信号先经过信号预处理模块，所述信号预处理模块用于将所述信号去直流、IQ幅度均衡、AGC增益控制和匹配滤波之后送入信号跟踪模块，同时将匹配滤波前后的信号均送入捕获模块进行载波频率的粗捕获和精捕获；所述粗捕获和精捕获的捕获结果分别用于锁频环和信号跟踪 模块中的锁相环；信号跟踪模块完成载波同步和符号/位同步之后进行软判决，将数据以并行总线方式输出。
进一步的，所述信号捕获模块包括载波粗捕获模块，所述载波粗捕获模块，捕获结果载波精度≤1MHz，且所述粗捕获模块的输出结果用于锁频环的鉴频结果以及作为精捕获模块的输入控制。
进一步的，所述信号捕获模块包括载波精捕获模块，所述载波精捕获模块用于得到比粗捕获结果更高频率精度的载波频率，输出频率控制字供跟踪模块的锁相环使用，且载波精捕模块中的积分用于降低采样率以及用于实现滤波作用、抑制载波频率段附近带外的噪声以提升信噪比。
进一步的，所述载波环路对输入载波进行实时同频同相的跟踪，对位进行同频同相的跟踪，精准对准位的中间位置，进行定时提取。
进一步的，采用早迟门锁相环进行位环的跟踪。
本发明的有益效果是：
(1)本发明能够完成超高带宽/超高速率的信号均衡，从高动态范围的调制信号中快速完成载波捕获、跟踪以及信息数据解调恢复。本发明提出的方案中，先将残留载波设置到接收机的载波捕获范围(扫描截获)，再通过对本振激光器的频率调整来将残留载波牵引至MHz级别(锁频牵引)，最后再通过精准的频率捕获手段得到精确的载波频率，从而使得残留载波进入载波跟踪锁相环的快捕带内，完成载波捕获后，再进行载波跟踪以及数据恢复处理。
(2)本发明采用粗捕获(频率牵引，消除载波高多普勒频移的消除)将残留载波牵引到MHz级别，通过精准频率捕获相结合的方式，过精准的频率捕获手段得到精确的载波频率。
(3)本发明提供一种卫星激光宽带解调恢复装置，能够完成超高带宽/超高速率的信号均衡，从高动态范围的调制信号中快速完成载波捕获、跟踪以及信息数据解调恢复。本发明提出的方案中，先将残留载波设置到接收机的载波捕获范围(扫描截获)，再通过对本振激光器的频率调整来将残留载波牵引至MHz级别(锁频牵引)，最后再通过精准的频率捕获手段得到精确的载波频率，从而使得残留载波进入载波跟踪锁相环的快捕带内。完成载波捕获后，再进行载波跟踪以及数据恢复处理。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1为本发明的载波跟踪环路原理结构框图；
图2为本发明的跟踪模块的运行流程示意图；
图3为本发明的信号处理流程示意图；
图4为信号处理结构图；
图5为模块软件结构图；
图6为粗捕获模块工作示意图；
图7为信号状态仿真图；
图8为粗捕获结果仿真图(纵坐标不代表绝对值)；
图9为精捕获结果仿真图(纵坐标不代表绝对值)；
图10为信号状态仿真图；
图11为粗捕获结果仿真图(纵坐标不代表绝对值)；
图12为精捕获结果仿真图(纵坐标不代表绝对值)。
具体实施方式
下面结合附图进一步详细描述本发明的技术方案，但本发明的保护范围不局限于以下所述。本说明书中公开的所有特征，或隐含公开的所有方法或过程中的步骤，除了互相排斥的特征和/或步骤以外，均可以任何方式组合。
本说明书(包括任何附加权利要求、摘要和附图)中公开的任一特征，除非特别叙述，均可被其他等效或具有类似目的的替代特征加以替换。即，除非特别叙述，每个特征只是一系列等效或类似特征中的一个例子而已。
下面将详细描述本发明的具体实施例，应当注意，这里描述的实施例只用于举例说明，并不用于限制本发明。在以下描述中，为了提供对本发明的透彻理解，阐述了大量特定细节。然而，对于本领域普通技术人员显而易见的是：不必采用这些特定细节来实行本发明。在其他实例中，为了避免混淆本发明，未具体描述公知的电路，软件或方法。
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
在对实施例进行描述之前，需要对一些必要的术语进行解释。例如：
若本申请中出现使用“第一”、“第二”等术语来描述各种元件，但是这些元件不应当由这些术语所限制。这些术语仅用来区分一个元件和另一个元件。因此，下文所讨论的“第一”元件也可以被称为“第二”元件而不偏离本发明的内容。应当理解的是，若提及一元件“连 接”或者“联接”到另一元件时，其可以直接地连接或直接地联接到另一元件或者也可以存在中间元件。相反地，当提及一元件“直接地连接”或“直接地联接”到另一元件时，则不存在中间元件。
在本申请中出现的各种术语仅仅用于描述具体的实施方式的目的而无意作为对本发明的限定，除非上下文另外清楚地指出，否则单数形式意图也包括复数形式。
当在本说明书中使用术语“包括”和/或“包括有”时，这些术语指明了所述特征、整体、步骤、操作、元件和/或部件的存在，但是也不排除一个以上其他特征、整体、步骤、操作、元件、部件和/或其群组的存在和/或附加。
如图1～12所示，一种卫星激光宽带解调方法，包括：
S21，扫描截获，先将残留载波设置到接收机的载波捕获范围；
S22，锁频牵引，再通过对本振激光器的频率调整来将残留载波牵引至MHz级别；
S23，再通过精准的频率捕获手段得到精确的载波频率，从而使得残留载波进入载波跟踪锁相环的快捕带内。
进一步的，在步骤S21前，包括信号预处理步骤S1，在步骤S1中完成包含残留多普勒载波信号的预处理，包括去直流、IQ幅度均衡、AGC增益控制、匹配滤波四个环节，其中去直流环节的目的是为去除信号中的直流成分，以便完全消除载波分量；IQ幅度均衡补偿I、Q路幅度相位的不均衡；通过AGC增益控制将信号幅值调整到适于处理；匹配滤波则对噪声信号进行滤除。
进一步的，在步骤S23之后，包括载波跟踪步骤S3，在步骤S3中载波环路对输入载波进行实时同频同相的跟踪，对位进行同频同相的跟踪，精准对准位的中间位置，进行定时提取。
进一步的，在步骤S3中，采用早迟门锁相环进行位环的跟踪。
进一步的，在步骤S3后执行步骤S4，包括相位模糊处理、差分译码、帧同步、状态控制、解扰及译码环节，用于实现对步骤三中位同步后数据的恢复处理。
一种卫星激光宽带解调装置，包括信号预处理模块、信号捕获模块和信号跟踪模块；信号先经过信号预处理模块，所述信号预处理模块用于去直流、IQ幅度均衡、AGC增益控制和匹配滤波之后送入信号跟踪模块，同时将匹配滤波前后的信号均送入捕获模块进行载波频率的粗捕获和精捕获，两种捕获结果分别用于锁频环和信号跟踪模块中的锁相环使用；信号跟踪模块完成载波同步和符号/位同步之后进行软判决，将数据以并行总线方式输出。
进一步的，所述信号捕获模块包括载波粗捕获模块，所述载波粗捕获模块，捕获结果载波精度≤1MHz，且所述粗捕获模块的输出结果包括两方面用途：一是用于锁频环的鉴频结果， 二是作为精捕获模块的输入控制。
进一步的，所述信号捕获模块包括载波精捕获模块，所述载波精捕获模块用于得到比粗捕获结果更高频率精度的载波频率，输出频率控制字供跟踪模块的锁相环使用，且载波精捕模块中的积分有两个方面的用途：一是降低采样率，二是实现滤波作用，抑制载波频率段附近带外的噪声，提升信噪比。
进一步的，载波环路对输入载波进行实时同频同相的跟踪，对位进行同频同相的跟踪，精准对准位的中间位置，进行定时提取。
进一步的，采用早迟门锁相环进行位环的跟踪。
一种卫星激光宽带解调方法，包括以下步骤：
步骤一，信号预处理，完成包含残留多普勒载波信号的预处理，包括去直流、IQ幅度均衡、AGC增益控制、匹配滤波四个环节，其中去直流环节的目的为去除信号中的直流成分，以便完全消除载波分量；IQ幅度均衡补偿I、Q路幅度相位的不均衡、通过AGC增益控制将信号幅值调整到适于处理，匹配滤波则进一步对噪声信号进行滤除。
步骤二、载波捕获，分三步骤实现：扫描截获、锁频牵引、频率精捕。主要完成信号中载波频率的捕获，分为粗捕获和精捕获，粗捕获用于锁频环路的控制(实现锁频牵引)，需要对大动态范围变化的载波频率进行捕获；精捕获(频率精捕)的载波频率结果用于载波锁相环的初始频率输入。
步骤三、载波跟踪，在完成捕获后，对载波频率进行了粗略估计，而没有相位的信息。为了彻底去除数字中频输入信号中的载波，使其从中频下变频到基带，需要使得本地恢复的载波跟输入载波同频同相。那么就需要载波环路对输入载波进行实时同频同相的跟踪。为了恢复出比特流，需要对位进行同频同相的跟踪，精准对准位的中间位置，进行定时提取。本发明使用早迟门(超前滞后)锁相环进行位环的跟踪。
步骤四、信号恢复，包括相位模糊处理、差分译码、帧同步、状态控制、解扰及译码环节，实现对位同步后数据的恢复处理。
本发明还提供了一种卫星激光宽带解调恢复装置，包括信号预处理、信号捕获、信号跟踪三大模块，工作时钟频率固定在信号随路时钟156.25MHz(ADC的采样中心频率固定为5GHz)。信号先经过信号预处理(去直流、IQ幅度均衡、AGC增益控制、匹配滤波)之后送入信号跟踪模块，同时将匹配滤波前后的信号均送入捕获模块进行载波频率的粗捕获和精捕获，2种捕获结果分别用于锁频环和信号跟踪模块中的锁相环使用。信号跟踪模块完成载波同步(载波锁相环)和符号/位同步(符号/位锁相环)之后进行软判决，将数据以并行总线方式输出。
载波粗捕获：模块需要捕获的载波频率范围为±500MHz(激光接收时多普勒最大可达±5GHz，超过±500MHz时，需要用到根据粗捕获幅度信息来控制激光本振扫描，以使接收残留载波调入±500MHz范围内)，捕获结果载波精度需要≤1MHz。载波粗捕获的输入为数字匹配滤波前的数据，因为其残留载波大的时候，信号频谱将超过滤波器的带宽，信号能量将被部分滤除，将影响捕获的结果。
粗捕获模块的输出结果有两方面用途：一是用于锁频环的鉴频结果，二是作为精捕获模块的输入控制(幅值用于判断是否应该启动精捕获，频率字作为精捕获的DDC的预补偿载波频率)。
载波精捕获：得到比粗捕获结果更高频率精度的载波频率，输出频率控制字供跟踪模块的锁相环使用。该模块需要捕获的载波频率范围为±20MHz，捕获结果载波精度需要≤200kHz。载波精捕获的输入为数字匹配滤波后的数据(即与跟踪模块使用同样的输入数据)。
载波精捕模块中的积分(分段积分)有两方面的作用：一是降低采样率，二是实现滤波作用，抑制载波频率段附近带外的噪声，提升信噪比。精捕获模块中采用先积分、后FFT的方式实现，即使在最大多普勒动态效应下，捕获精度为81.37kHz。
载波跟踪环：主要完成信号载波、位(符号)的跟踪(同步)、符号判决(软判决)、信噪比估计。
跟踪环路是接收机的重要组成部分，主要包含：载波跟踪环路、符号环路。在完成捕获后，对载波频率进行了粗略估计，而没有相位的信息。为去除数字中频输入信号中的载波，使其从中频下变频到基带，需要使得本地恢复的载波跟输入载波同频同相。那么就需要载波环路对输入载波进行实时同频同相的跟踪。本发明使用Costas环路实现载波跟踪。为了恢复出比特流，需要对位进行同频同相的跟踪，精准对准位的中间位置，进行定时提取，选择早迟门(超前滞后)锁相环进行位环的跟踪。
高码率xPSK系统的跟踪环路原理框图如图1所示。
跟踪模块需要使用2个时钟，1个为解调数据域时钟i_clk，另一个为位同步NCO的工作时钟i_clk_dds。i_clk_dds先于i_clk到来，其复位释放(i_rst_dds)同样先于i_rst。
因此本跟踪模块在i_clk_dds时钟到来和i_rst_dds复位释放之后，位NCO最先工作，然后在i_clk有效和i_rst复位释放之后，跟踪模块内部其余逻辑进入初始状态，再得到精精捕载波结果输入之后，载波同步、位同步同时开始工作。本跟踪模块内部设置了对于载波同步的自动定时检测，一旦检测到载波同步失锁时，自动复位除位NCO、失锁定时检测模块外的所有模块，使得其基本进入复位初始态，等待下一次精捕获完成后重新开始2个环路的同步。
信号处理包括几个大的部分：信号预处理、信号捕获、信号跟踪、数据恢复、信道接收、 和接口处理等过程，详细处理过程如图3所示。
解调模块主要完成信号的解调，输出软判决数据。
本解调模块实现的内容即为上图中的载波提取、定时提取、抽判、并串转换。解调过程由软硬件共同实现，因为符号同步需要的定时提取需要依靠调整ADC的采样时钟的频率和相位来实现。
数字解调器按功能可分为4个主要过程：增益控制(AGC)、均衡补偿(IQ幅度补偿、相位补偿)、载波同步(包含载波捕获、载波跟踪)、位同步及符号判决(星座图解映射)。
解调器有三个主要环路：增益控制环路(AGC)、载波环(PLL)、位同步环(基于PLL技术)。三个环路可以独立并行的工作，在数字信号处理中使用了数字AGC，但是对于激光通信中收发激光器的频率飘移特性，需要使用一个锁频环路对接收光本振进行控制，本解调器模块负责锁频环中的鉴频计算。解调模块软件结构由信号预处理、信号捕获、信号跟踪三个模块组成，工作时钟频率固定在信号随路时钟156.25MHz，ADC的采样频率为以5GHz为中心可动态调整。信号先经过信号预处理(去直流、IQ幅度均衡、AGC增益控制、匹配滤波)之后送入信号跟踪模块，同时将匹配滤波前后的信号均送入捕获模块进行载波频率的粗捕获和精捕获，两种捕获结果分别用于锁频环和信号跟踪模块中的锁相环使用。信号跟踪模块完成载波同步(载波锁相环)和符号/位同步(符号/位锁相环)之后进行软判决，将数据以并行总线方式输出。
信号捕获模块，由于卫星运动和激光器本身的频率特性，接收机得到的载波多普勒高达±5GHz，此范围超过了常规接收机能够捕获的频率范围，且接收机相干解调时本身的数字频率补偿范围有限，因此需要先将残留载波设置到接收机的载波捕获范围(扫描截获)，然后再通过对本振激光器的频率调整来将残留载波牵引至MHz级别(锁频牵引)，最后再通过精准的频率捕获手段得到精确的载波频率，从而使得残留载波进入载波跟踪锁相环的快捕带内。采用粗捕获(频率牵引，消除载波高多普勒频移的消除)将残留载波牵引到MHz级别，通过精准的频率捕获手段得到精确的载波频率。
如图5所示，为模块软件结构示意图，
实现原理，傅里叶变换公式为：
Figure PCTCN2020109464-appb-000001
在IQ调制中：
Figure PCTCN2020109464-appb-000002
则：
Figure PCTCN2020109464-appb-000003
Figure PCTCN2020109464-appb-000004
则捕获频率会受到符号调制的影响，因此需要去除符号调制对载波频率的影响。左右平方：
Figure PCTCN2020109464-appb-000005
其中：(I+jQ) 2展开为I2-Q2+2IQJ；
对于BPSK、则此项中Q为0，对于QPSK，上式中I2的积分值等于Q2的积分值，两项可以互相抵消，则上式变为
BPSK:
Figure PCTCN2020109464-appb-000006
QPSK：
Figure PCTCN2020109464-appb-000007
对于BPSK来说，I 2的积分值已是常数，对于QPSK来说，需要再对上式取平方以消除2IQJ的影响，因此为了统计计算过程，对于BPSK与QPSK来说，均再次平方得到如下：
BPSK:
Figure PCTCN2020109464-appb-000008
QPSK：
Figure PCTCN2020109464-appb-000009
对于上式中除e x项以外，其余项的积分值为固定值，可设为A，则：
Figure PCTCN2020109464-appb-000010
为了消除QPSK中负号的影响，对上式的积分结果再取模值。
可知当(ω lo＝ω)时，有最大值；因此可以实现载波捕获。
捕获模块，完成载波的粗捕获，该模块需要捕获的载波频率范围为±500MHz(激光接收时多普勒最大可达±5GHz，超过±500MHz时，需要用到根据粗捕获幅度信息来控制激光本振 扫描，以使接收残留载波调入±500MHz范围内)，捕获结果载波精度需要≤1MHz。载波粗捕获的输入一定为数字匹配滤波前的数据，因为其残留载波大的时候，信号频谱将超过滤波器的带宽，信号能量将被部分滤除，将影响捕获的结果。
粗捕获模块的输出结果有两方面用途：一是用于锁频环的鉴频结果，二是作为精捕获模块的输入控制(幅值用于判断是否应该启动精捕获，频率字作为精捕获的DDC的预补偿载波频率)。
粗捕获模块作为锁频环路的鉴频部分，在整个锁频环路中工作示意图如下所示(绿色部分为载波粗捕获模块的部分)：
关于处理时延：捕获模块的处理时延(Td)由2部分构成。一是信号本身的输入时间T1(串行输入时间)。二是FFT处理的时延(T2)。在载波频率大动态变化的情况下，越长的输入数据时间将导致FFT峰值模糊，越长的处理时间将导致FFT输出的频率不能代表真实的频率值。目前粗捕获模块中的FFT设计点数为4096点，由此确定的设计参数如图6所示：即使在最大多普勒动态效应下，捕获精度为611.78kHz。
精捕获模块，模块完成载波的精捕获，得到比粗捕获结果更高频率精度的载波频率，输出频率控制信号跟踪模块的锁相环使用。该模块需要捕获的载波频率范围为±20MHz，捕获结果载波精度≤200kHz。载波精捕获的输入为数字匹配滤波后的数据(即与跟踪模块使用同样的输入数据)。
载波精捕模块中的积分(分段积分)有2个方面的作用：一是降低采样率，二是实现滤波作用，抑制载波频率段附近带外的噪声，提升信噪比。即使在最大多普勒动态效应下，捕获精度为81.37kHz。
仿真
根据选定的积分、FFT参数，创建了代码进行数据仿真。仿真的数据使用了2种：一种为仿真产生的理想无相噪、无多普勒情况下的BPSK信号。另外一种为实测数据，以下为仿真结果：
由上可知，可知最终的捕获载波频率为-499.115MHz，与设定值只相差8kHz。
(1)产生的BPSK信号，无相噪、无多普勒、信噪比10dB，设置载波为-499.123MHz下的仿真图：
图7，信号状态仿真图；
图8，粗捕获结果仿真图(纵坐标不代表绝对值)；
图9，精捕获结果仿真图(纵坐标不代表绝对值)；
由上可知，可知最终的捕获载波频率为-499.115MHz，与设定值只相差8kHz。
(2)激光通信时离线的数据-单载波：中等相噪、信噪比达15dB以上下的仿真图：
图10，信号状态仿真图；
图11，粗捕获结果仿真图(纵坐标不代表绝对值)；
图12，精捕获结果仿真图(纵坐标不代表绝对值)；
信号跟踪模块，主要完成信号载波、位(符号)的跟踪(同步)、符号判决(软判决)、信噪比估计。
跟踪环路是接收机的重要组成部分，主要包含：载波跟踪环路、符号环路。在完成捕获后，对载波频率进行了粗略估计，而没有相位的信息。为了彻底去除数字中频输入信号中的载波，使其从中频下变频到基带，需要使得本地恢复的载波跟输入载波同频同相。那么就需要载波环路对输入载波进行实时同频同相的跟踪。本发明采用Costas环路实现载波跟踪。为了恢复出比特流，需要对位进行同频同相的跟踪，精准对准位的中间位置，进行定时提取。本方案使用早迟门(超前滞后)锁相环进行位环的跟踪。高码率xPSK系统的跟踪环路原理框图如图1所示，
载波同步锁相环中的预积分：在FPGA实现时，因为计算时延的约束，将积分点数使用2 n次方，且FPGA对积分后的数据进行取平均值操作。
两个环路分别使用的鉴相器如下。
Figure PCTCN2020109464-appb-000011
上表中的符号含义为：
(1)I p(n)和Q p(n)为当前时刻I路和Q路即时支路的累加和(预积分后的值)。
(2)sign表示采样点的符号位(正数取1，负数取0)。
(3)Y I(r)和Y Q(r)表示第r个符号I、Q两路在判决时刻的采样点值，Y I(r-1/2)和Y Q(r-1/2)表示介于第r和r-1个符号的中间采样点值。
关于位同步环路鉴相说明：从鉴相公式可以知道看出，如果第r个采样点和第r-1个采样点的极性相反，那么则r-1/2这个样点应该为零或者在零附近正负跳动；如果第r和r-1个样点的极性相同，则sign(YI(r))-sign(YI(r-1))＝0。如果已位同步，那么其误差信号error(r)为0。如果超前，那么其误差为负，如果滞后，那么其误差为正。
环路滤波器，两个环路的环路滤波器均采用的是一阶理想有源比例积分滤波器(构成二阶环路)，环路参数(T、K1、K2)的确定主要是要先确定环路带宽B L，然后得到积分时间T、和ω n，再根据公式计算得到K1、K2。
(1)环路参数的选择主要依据环路要跟踪的信号的动态指标(输入信号相噪、所需快捕带宽、最大捕获扫描速率、最大同步扫描速率)以及锁相环输出指标(环路信噪比、快捕时间、频率斜升稳态相差)来确定。
(2)处理时延对积分时间的限制。在锁相环的FPGA数字实现过程中，环路处理上是存在时延，一旦处理时延接近或者达到或超过积分时间，环路的性能将被破坏，甚至出现环路震荡无法锁定的情况。因此在高环路带宽的FPGA环路实现过程中，处理时延限制了环路带宽的提高。先根据处理时延先计算能够提供的最小积分时间，再依据环路带宽与积分时间的关系、以及便于数字实现积分后求平均值的动作折中选择积分时间和环路带宽。
关于本发明中时延对积分实现/环路带宽限制的分析：
载波同步锁相环
该锁相环在FPGA内部全数字化实现，因此环路的延时来自于FPGA的数据计算时延，其环路计算需要8个时钟周期。ADC输出的随路时钟分频后作为锁相环工作的主时钟，该时钟频率为156.25MHz(周期6.4ns)，因此环路时延为51.2ns。根据处理时延与积分时间制约关系，因此积分时间不得低于此值。
位同步锁相环
该锁相环路的NCO输出直接控制ADC的采样时钟，因此该环路延迟主要由两部分组成：FPGA环路计算、NCO的DAC传播时延。
首先估算一下环路的积分时间：该位同步相位跟踪时的位多普勒动态较小(约1KHz/s)，静态多普勒又有预补偿，因此环路带宽可以只要KHz级别，预积分时间可以达到20us左右。
FPGA环路计算时延20个时钟周期、DAC传播时延为4时钟周期+21.5ns。因此在环路时钟为156.25MHz(周期6.4ns)和DAC转换率为50MHz(20ns)的情况下，环路时延总共为229.5ns。该时延与预积分时间20us相比是一个小量，因此环路时延对环路性能的影响可以忽略。
(3)激光通信中光载波的相噪制约载波同步环路带宽。在激光通信中，收、发激光器本身的相噪是决定锁相环参数选择的主要因素，确定积分点数为16点(积分时间为102.40ns)，对应更新频率为9.77MHz，得到环路带宽为244.14kHz。
(4)激光通信中码/位多普勒预补精度制约了位同步环路带宽。本发明中码多普勒带宽在 卫星运动下可达±50kHz大小，而其码多普勒速率为1kHz/s和码多普勒加速度1kHz/s2相比码多普勒带宽对环路带宽的限制均较小。多普勒预补后的精度就是位同步环路需要提供的快捕带宽，综合选择位同步带宽为1kHz。
信噪比估计模块
信噪比估计使用符号/位环路输出的Idata和Qdata两路软判决前的数据，旋转成BPSK星座图之后才能进行如下计算；对于并行数据，只需要取其中一路即可)，计算公式如下。
Figure PCTCN2020109464-appb-000012
FPGA实现的时候，先将每个数据点计算I 2-Q 2、2Q 2，然后计算数据的平均值mean(I 2-Q 2),mean(2Q 2),然后得到mean(I 2-Q 2)*16，最后计算除法。取整数商之后，得到信噪比放大16倍的值。
位同步NCO
位同步的NCO(DDS)输出的频率是ADC采样时钟的一部分，ADC采样时钟又是整个解调器的工作时钟。
跟踪模块运行流程
跟踪模块内部按如下流程运行：
跟踪模块需要使用2个时钟，1个为解调数据域时钟i_clk，另一个为位同步NCO(DDS)的工作时钟i_clk_dds。i_clk_dds先于i_clk到来，其复位释放(i_rst_dds)同样先于i_rst。
因此本跟踪模块在i_clk_dds时钟到来和i_rst_dds复位释放之后，位NCO最先工作，然后在i_clk有效和i_rst复位释放之后，跟踪模块内部其余逻辑进入初始状态，再得到精捕载波结果输入之后，载波同步、位同步同时开始工作。本跟踪模块内部设置了对于载波同步的自动定时检测，一旦检测到载波同步失锁时，自动复位除位NCO、失锁定时检测模块外的所有模块，使得其基本进入复位初始态(除了位NCO的初始相位无法恢复外，初始相位不影响位跟踪过程)，等待下一次精捕获完成后重新开始载波环和位环的同步。
在本实施例中的其余技术特征，本领域技术人员均可以根据实际情况进行灵活选用和以满足不同的具体实际需求。然而，对于本领域普通技术人员显而易见的是：不必采用这些特定细节来实现本发明。在其他实例中，为了避免混淆本发明，未具体描述公知的算法，方法或系统等，均在本发明的权利要求书请求保护的技术方案限定技术保护范围之内。
对于前述的方法实施例，为了简单描述，故将其都表述为一系列的动作组合，但是本领域技术人员应该知悉，本申请并不受所描述的动作顺序的限制，因为依据本申请，某一些步骤可以采用其他顺序或者同时进行。其次，本领域技术人员也应该知悉，说明书中所描述的 实施例均属于优选实施例，所涉及的动作和单元并不一定是本申请所必须的。
本领域技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法实现所描述的功能，但是这种实现不应超出本发明的范围。
所揭露的系统、模块和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例，仅仅是示意性的，例如，所述单元的划分，可以仅仅是一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以说通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述分立部件说明的单元可以是或者也可以不收物理上分开的，作为单元显示的部件可以是或者可以不收物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例的方案的目的。
所述功能如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读存储介质中。基于这样的理解，本发明的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本发明各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(Read-Only Memory，ROM)、随机存取存储器(Random Access Memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
本领域普通技术人员可以理解实现上述实施例的方法中的全部或部分流程，是可以通过计算机程序来指令相关的硬件来完成，所述的程序可存储于计算机可读取存储介质中，该程序在执行时，可包括如上述各方法的实施例的流程。其中，所述的存储介质可为磁碟、光盘、ROM、RAM等。
以上所述仅是本发明的优选实施方式，应当理解本发明并非局限于本文所披露的形式，不应看作是对其他实施例的排除，而可用于各种其他组合、修改和环境，并能够在本文所述构想范围内，通过上述教导或相关领域的技术或知识进行改动。而本领域人员所进行的改动和变化不脱离本发明的精神和范围，则都应在本发明所附权利要求的保护范围内。

Claims (10)

  1. 一种卫星激光宽带解调方法，其特征在于，包括以下步骤：
    S21，扫描截获，先将残留载波设置到接收机的载波捕获范围；
    S22，锁频牵引，再通过对本振激光器的频率调整来将残留载波牵引至MHz级别；
    S23，再通过精准的频率捕获手段得到精确的载波频率，从而使得残留载波进入载波跟踪锁相环的快捕带内。
  2. 根据权利要求1所述的卫星激光宽带解调方法，其特征在于，在步骤S21前，包括信号预处理步骤S1，在步骤S1中完成包含残留多普勒载波信号的预处理，包括去直流、IQ幅度均衡、AGC增益控制以及匹配滤波四个环节，其中所述去直流环节用于去除信号中的直流成分，以便完全消除载波分量；IQ幅度均衡补偿I、Q路幅度相位的不均衡；通过AGC增益控制将信号幅值调整到适于处理；匹配滤波则对噪声信号进行滤除。
  3. 根据权利要求1或2所述的卫星激光宽带解调方法，其特征在于，在步骤S23之后，包括载波跟踪步骤S3，在步骤S3中载波环路对输入载波进行实时同频同相的跟踪，对位进行同频同相的跟踪，精准对准位的中间位置，进行定时提取。
  4. 根据权利要求3所述的一种卫星激光宽带解调方法，其特征在于，在步骤S3中，采用早迟门锁相环进行位环的跟踪。
  5. 根据权利要求4所述的一种卫星激光宽带解调方法，其特征在于，在步骤S3后执行步骤S4，所述步骤S4包括相位模糊处理、差分译码、帧同步、状态控制、解扰及译码环节，用于实现对步骤S3中位同步后数据的恢复处理。
  6. 一种卫星激光宽带解调装置，其特征在于，包括信号预处理模块、信号捕获模块和信号跟踪模块；信号先经过信号预处理模块，所述信号预处理模块用于将所述信号去直流、IQ幅度均衡、AGC增益控制和匹配滤波之后送入信号跟踪模块，同时将匹配滤波前后的信号均送入捕获模块进行载波频率的粗捕获和精捕获；所述粗捕获和精捕获的捕获结果分别用于锁频环和信号跟踪模块中的锁相环；信号跟踪模块完成载波同步和符号/位同步之后进行软判决，将数据以并行总线方式输出。
  7. 根据权利要求6所述的卫星激光宽带解调装置，其特征在于，所述信号捕获模块包括载波粗捕获模块，所述载波粗捕获模块，捕获结果载波精度≤1MHz，且所述粗捕获模块的输出结果用于锁频环的鉴频结果以及作为精捕获模块的输入控制。
  8. 根据权利要求6所述的卫星激光宽带解调装置，其特征在于，所述信号捕获模块包括载波精捕获模块，所述载波精捕获模块用于得到比粗捕获结果更高频率精度的载波频率，输出频率控制字供跟踪模块的锁相环使用，且载波精捕模块中的积分用于降低采样率以及用于实现滤波作用、抑制载波频率段附近带外的噪声以提升信噪比。
  9. 根据权利要求6所述的卫星激光宽带解调装置，其特征在于，所述载波环路对输入载波进行实时同频同相的跟踪，对位进行同频同相的跟踪，精准对准位的中间位置，进行定时提取。
  10. 根据权利要求9所述的卫星激光宽带解调装置，其特征在于，采用早迟门锁相环进行位环的跟踪。
PCT/CN2020/109464 2020-08-17 2020-08-17 一种卫星激光宽带解调方法与装置 WO2022036489A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
PCT/CN2020/109464 WO2022036489A1 (zh) 2020-08-17 2020-08-17 一种卫星激光宽带解调方法与装置
CN202080077073.4A CN114667717B (zh) 2020-08-17 2020-08-17 一种卫星激光宽带解调方法与装置
US17/777,780 US20220416896A1 (en) 2020-08-17 2020-08-17 Method and apparatus for satellite laser broadband demodulation
EP20949702.3A EP4024798A4 (en) 2020-08-17 2020-08-17 SATELLITE LASER WIDE BAND DEMODULATION METHOD AND APPARATUS

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2020/109464 WO2022036489A1 (zh) 2020-08-17 2020-08-17 一种卫星激光宽带解调方法与装置

Publications (1)

Publication Number Publication Date
WO2022036489A1 true WO2022036489A1 (zh) 2022-02-24

Family

ID=80322456

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/109464 WO2022036489A1 (zh) 2020-08-17 2020-08-17 一种卫星激光宽带解调方法与装置

Country Status (4)

Country Link
US (1) US20220416896A1 (zh)
EP (1) EP4024798A4 (zh)
CN (1) CN114667717B (zh)
WO (1) WO2022036489A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115561786A (zh) * 2022-09-14 2023-01-03 福建福大北斗通信科技有限公司 一种应用于北斗三号基带的可变带宽码环处理方法
CN116455460A (zh) * 2023-06-16 2023-07-18 成都星联芯通科技有限公司 低频直流分量滤除方法、解调器及卫星通信设备

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115825560B (zh) * 2023-02-17 2023-05-23 青岛鼎信通讯股份有限公司 一种基于频率跟踪技术的低压电网智能核相方法
CN117200884B (zh) * 2023-11-02 2024-03-22 北京融为科技有限公司 基于多源融合的激光波长捕获方法、装置、设备及介质

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104378130A (zh) * 2014-11-26 2015-02-25 成都中远信电子科技有限公司 一种用于无人机地空宽带通信系统的接收终端
US20150118980A1 (en) * 2013-10-29 2015-04-30 Qualcomm Incorporated Transmitter (tx) residual sideband (rsb) and local oscillator (lo) leakage calibration using a reconfigurable tone generator (tg) and lo paths
CN105429918A (zh) * 2015-10-23 2016-03-23 上海航天测控通信研究所 一种用于深空测控信号的快速捕获方法
CN109039471A (zh) * 2018-09-13 2018-12-18 上海微小卫星工程中心 一种应用于高速激光通信的数模混合解调方法

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7558340B2 (en) * 2003-12-01 2009-07-07 Lg Electronics Inc. VSB receiver and carrier recovery apparatus thereof
GB2494689A (en) * 2011-09-16 2013-03-20 Excelerate Technology Ltd Managing a satellite support mechanism
EP2979386A1 (en) * 2013-05-02 2016-02-03 Comtech EF Data Corp. Rapid carrier acquisition for digital communication receiver
CN107121685A (zh) * 2017-06-08 2017-09-01 南京理工大学 一种微型星载高动态gnss接收机及其导航方法
CN108072883A (zh) * 2017-12-24 2018-05-25 航天天绘科技有限公司 一种多航天器兼容互操作的信号多模接收锁定处理方法
WO2019131396A1 (ja) * 2017-12-27 2019-07-04 日本電気株式会社 信号処理装置及び信号処理方法
CN111308518A (zh) * 2020-02-20 2020-06-19 湖南迈克森伟电子科技有限公司 卫星接收机高效多制式自适应捕获与跟踪装置
CN111239776B (zh) * 2020-02-20 2022-05-10 湖南迈克森伟电子科技有限公司 卫星接收机高效多制式自适应捕获与跟踪方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150118980A1 (en) * 2013-10-29 2015-04-30 Qualcomm Incorporated Transmitter (tx) residual sideband (rsb) and local oscillator (lo) leakage calibration using a reconfigurable tone generator (tg) and lo paths
CN104378130A (zh) * 2014-11-26 2015-02-25 成都中远信电子科技有限公司 一种用于无人机地空宽带通信系统的接收终端
CN105429918A (zh) * 2015-10-23 2016-03-23 上海航天测控通信研究所 一种用于深空测控信号的快速捕获方法
CN109039471A (zh) * 2018-09-13 2018-12-18 上海微小卫星工程中心 一种应用于高速激光通信的数模混合解调方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4024798A4 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115561786A (zh) * 2022-09-14 2023-01-03 福建福大北斗通信科技有限公司 一种应用于北斗三号基带的可变带宽码环处理方法
CN115561786B (zh) * 2022-09-14 2023-08-15 福建福大北斗通信科技有限公司 一种应用于北斗三号基带的可变带宽码环处理方法
CN116455460A (zh) * 2023-06-16 2023-07-18 成都星联芯通科技有限公司 低频直流分量滤除方法、解调器及卫星通信设备
CN116455460B (zh) * 2023-06-16 2023-08-25 成都星联芯通科技有限公司 低频直流分量滤除方法、解调器及卫星通信设备

Also Published As

Publication number Publication date
US20220416896A1 (en) 2022-12-29
EP4024798A4 (en) 2022-11-23
CN114667717A (zh) 2022-06-24
EP4024798A1 (en) 2022-07-06
CN114667717B (zh) 2024-02-09

Similar Documents

Publication Publication Date Title
WO2022036489A1 (zh) 一种卫星激光宽带解调方法与装置
CN111343125B (zh) 32apsk调制体制接收机同步方法
US5440265A (en) Differential/coherent digital demodulator operating at multiple symbol points
US8306156B2 (en) Data aided detection of spectrum inversion
CN106656168B (zh) 时钟数据恢复装置及方法
CN109831402B (zh) 16apsk信号载波相位同步及其判锁定方法
WO1997030511A1 (en) Apparatus for generating timing signal for a digital television signal receiver
JPH10308715A (ja) 受信装置および受信方法
CN108270715A (zh) 适合高阶4096-qam的载波恢复系统和方法
CN105515639B (zh) 一种通用卫星高速数传信号定时同步方法
CN106534023B (zh) 一种非合作通信中mqam的定时载波联合同步方法
CN106656400A (zh) Pcma系统时延抖动情况下的精确频差快速捕获方法
JP2932861B2 (ja) 位相同期検出回路
US5247543A (en) Carrier aquisition apparatus for digital satellite communication system
CN109525533B (zh) 一种应用于mapsk调制的载波相位误差提取系统
CN112511182B (zh) 一种星载测控数传接收装置
CN112468421B (zh) 一种基于q次方极性判决的载波相位恢复方法及系统
CN116016072B (zh) 零中频结构低复杂度msk正交解调装置及其解调方法
CN108712190B (zh) 多载波跟踪方法及跟踪装置
CN110224807A (zh) 一种基于agc频偏预估的载波同步方法及系统
US4794623A (en) Recovery of carrier signal from QAM double sideband suppressed carrier IF signal for use in synchronous demodulation
US6650715B1 (en) Apparatus for recovering decision-directed carrier
CN110048759B (zh) 自适应跟踪宽带接收信号环路参数的方法
Zhuravlev Synchronization algorithm for a satellite communication signals demodulator in high carrier shift conditions
Shevyakov et al. Carrier recovery techniques analysis for PSK signals

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20949702

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2020949702

Country of ref document: EP

Effective date: 20220330

NENP Non-entry into the national phase

Ref country code: DE