A kind of gmsk signal demodulation method

Abstract

The invention discloses a GMSK signal demodulation method, which belongs to the technical field of signal modulation characteristic test of electronic measuring instruments. The invention designs a demodulation test method for the modulation characteristic test of GMSK signal, and solves the problem by adopting a forward demodulation scheme. It solves the contradiction between short data and high-precision demodulation caused by the loop lock-in process in the existing feedback demodulation scheme, and can adapt to short data demodulation tests. It is applicable to a wide range of test scenarios and has strong applicability in test scenarios; By improving the carrier synchronization link in the forward demodulation scheme and adding precise frequency offset estimation, it not only ensures the range of frequency offset estimation, but also improves the estimation accuracy, realizes high-precision demodulation, and solves the problem of demodulation in existing forward demodulation schemes. The problem of low precision.

Description

technical field [0001] The invention belongs to the technical field of signal modulation characteristic testing of electronic measuring instruments, and in particular relates to a GMSK signal demodulation method. Background technique [0002] As a continuous phase modulation (CPM) signal, the GMSK signal is widely used in military radio stations, GSM systems, GPRS systems, Digital TV, satellite communication, ship automatic identification system (AIS), aviation data link and other fields have been widely used. However, the transmitter of the GMSK communication system usually needs to test the modulation performance before it is applied, and at the same time, some fault diagnosis of the transmitting equipment also needs to be tested for the modulation performance. The signal analyzer has developed from a single spectrum test to a multi-functional test instrument for testing and analyzing signals from multiple angles in the time domain, frequency domain, and modulation domain...

AI Technical Summary

Problems solved by technology

[0007] The disadvantages of the existing technical solutions are: firstly, there is a loop lock-in process in the synchronization, and the lock-in time is long, which is not suitable for demodulating short data; secondly, programmable logic devices are mostly used for implementation, and the implementation cost is high, and the program portability is poor; thirdly, When it adopts the non-phase-locked loop forward synchronous demodulation scheme, the carrier synchronization frequency offset estimation accuracy is not enough, resulting in low demodulation index

Based on the above shortcomings, the existing technical solutions are difficult to apply to signal analysis and measuring instruments

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