A kind of signal demodulation system and demodulation method

Abstract

The embodiment of the present invention relates to the field of communications, and discloses a signal demodulation system and a demodulation method, comprising: a signal synchronizer, configured to calculate a frequency offset estimation value and a frame synchronization estimation result according to an input frequency modulation signal and a local signal; a frequency offset canceller, used for eliminating the estimated residual frequency offset in the FM signal according to the estimated value of the frequency offset to obtain a first signal; an adaptive modulation coefficient coherent demodulator, used for according to the first signal and the frame synchronization estimation result , output the demodulation result of the FM signal; wherein, the modulation coefficient of the signal synchronizer and the modulation coefficient of the adaptive modulation coefficient coherent demodulator are preset to the same coefficient value, and different coefficient values ​​correspond to different demodulation architectures. The present invention realizes coherent demodulation by presetting the modulation coefficient of the signal synchronizer and the modulation coefficient of the adaptive modulation coefficient coherent demodulator to the same coefficient value, and different coefficient values ​​correspond to different demodulation structures, and eliminates variation influence of the modulation factor.

Description

technical field [0001] Embodiments of the present invention relate to the field of communications, and in particular, to a signal demodulation system and a demodulation method. Background technique [0002] An FSK (Frequency Shift Keying) signal is a signal used for high-speed data transmission. The transmitter of the FSK modulated signal usually sets a range for the modulation factor of FSK. For example, the modulation factor of the FSK of the BT architecture is usually set to 0.28 to 0.35, and the modulation factor of the FSK of the BLE architecture is usually set to 0.45 to 0.55. Usually the receiving end cannot perform coherent demodulation for the changing modulation coefficient. During the demodulation process of the FM signal, the residual frequency offset in the FM signal needs to be considered. The existence of these residual frequency offsets makes the demodulation process of the FM signal not coherent demodulation. , thereby affecting the demodulation result of t...

AI Technical Summary

Problems solved by technology

The usual receiving end cannot perform coherent demodulation for changing modulation coefficients. During the demodulation process of FM signals, the residual frequency offset in the FM signal needs to be considered. The existence of these residual frequency offsets makes the demodulation process of FM signals not coherent demodulation. , thus affecting the demodulation result of the FM signal

In the existing schemes, non-coherent demodulation methods are mostly adopted, such as split filter envelope detection method, zero-crossing detection method, etc., but these methods have low frequency band utilization and are difficult to accurately detect

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