TCM-8PSK baseband signal demodulation method

Abstract

The invention discloses a TCM-8PSK baseband signal demodulation method and relates to the technical field of communication. The demodulation method comprises the steps as follows: digital signals enter an FPGA (field programmable gate array), FFT (Fast Fourier Transform) signal fast capture is performed, and at the same time, the signals enter a lower sampling module; a first selector selects a signal carrier, and the signal carrier enters high-speed locking or low-speed locking synchronously; a lower frequency conversion module restores baseband IQ-channel signals; the baseband IQ-channel signals pass through an LPF (low pass filter) module respectively; the signals enter a carrier synchronization branch, flow out of the FPGA after entering a code element synchronization branch and then enter a DSP (digital signal processor); and information demodulated from the DSP is fed back to the first selector. The TCM-8PSK baseband signal demodulation method has the benefits as follows: the efficiency for realizing rapid capture and rapid synchronization of the signals in short-time burst communication is greatly improved; through adopting signal branching processing, the code element synchronization and the carrier synchronization use different sampling rates respectively, so that correct demodulation of the AD sampling rate and the symbol rate in a non-integer multiple relationship is realized.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to a TCM-8PSK baseband signal demodulation method. Background technique [0002] TCM-8PSK is widely used in satellite communication, data link radio and other fields. TCM-8PSK short-packet burst communication is only suitable for coherent demodulation. The receiver usually needs to estimate the initial phase of the transmitting carrier and the carrier frequency offset between the transmitting and receiving ends, and then compensate the residual frequency offset through the tracking loop to achieve purpose of correct demodulation. The initial phase and frequency offset estimation and tracking process of the traditional method are often completed by hundreds of symbols, which has the advantage of being able to compensate for a large carrier frequency offset, but the tracking time is long, and the hardware overhead is generally large. [0003] For the short packet information ...

AI Technical Summary

Problems solved by technology

[0005] In FPGA, the processing of the feedback loop across clock domains with non-integer multiples is a difficult problem. This problem often causes timing instability. The actual locking effect cannot achieve the effect of simulation. How to avoid crossing clock domains is also very difficult. Important issues

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