GFSK digital double-channel demodulation method

Abstract

The invention discloses a GFSK (Gaussian Frequency Shift Keying) digital double-channel demodulation method. The method comprises the following steps: enabling baseband signals to pass through a positive pre-compensation filter module and a negative pre-compensation filter module respectively at the same time, setting a pre-compensation value by a register and setting different pre-compensation values dF according to a carrier offset range tolerable for a system; performing pre-compensation filtering on the baseband signals respectively, then performing precise estimation on signal frequency deviations, and then performing compensation filtering; then, performing differential operation to obtain a result which refers to enveloping of modulation signals of a transmitting terminal; after phase differentiation, enabling the baseband signals to pass through a module without direct-current components; processing input signals by a data recovery clock synchronization module to generate serial bit decoding output and also generate a corresponding clock signal to ensure that a latter stage can make use of the clock signal directly to perform sampling processing on bit signals; and then selecting to output which path of signals according to the quality of leading signals by a number follower. The GFSK digital double-channel demodulation method not only achieves utilization of the demodulation performance of an FFT (Fast Fourier Transform) module, but also occupies less hardware resources, and is easy to implement.

Description

technical field [0001] The invention relates to the technical field of digital demodulation, in particular to a GFSK digital dual-channel demodulation method. Background technique [0002] The carrier frequency is below 1G, and the supported data rate is as low as 1Khz. Since the sensitivity of the receiver is closely related to the signal bandwidth, the data rate can be reduced to improve the receiver sensitivity. When the signal data rate is on the order of 10khz, the frequency offset can be estimated simply by averaging the preamble, but the data rate On the order of 1khz, the signal-to-noise ratio will be very poor, and it is difficult to estimate the frequency offset by averaging. The general solution is to perform FFT on the signal to find the frequency deviation, but the FFT module will occupy a large circuit area. Contents of the invention [0003] In view of the above problems, the present invention provides a GFSK digital dual-channel demodulation method, which...

AI Technical Summary

Problems solved by technology

Since the sensitivity of the receiver is closely related to the signal bandwidth, the data rate can be reduced to improve the receiver sensitivity. When the signal data rate is on the order of 10khz, the frequency offset can be estimated simply by averaging the preamble, but the data rate On the order of 1khz, the signal-to-noise ratio will be very poor, and it is difficult to estimate the frequency offset by averaging

The general solution is to perform FFT on the signal to find the frequency deviation, but the FFT module will occupy a large circuit area

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