Digital remodulation and digital remodulating method for binary frequency shift keying signal

Abstract

The invention relates to a digital complex modulation method of a binary frequency shift keying signal. The method adopts the principle of complex signal processing to realize complex modulation and complex demodulation of a binary frequency shift keying (2FSK) signal, and the bandpass filter can be It is not necessary to design a wide variety of band-pass filters for binary frequency shift keying signals with different center frequencies, and only need to design a low-pass filter for binary frequency shift keying signals with the same transmission bandwidth. pass filter, which greatly reduces the complexity of the signal processing algorithm; there will be no fractional delay during demodulation, and there is no need to design a fractional delay filter; the product after complex multiplication does not need a low-pass filter Filtering, only the imaginary part is taken and the data demodulation decision is directly performed.

Description

technical field [0001] The invention relates to a binary frequency shift keying signal complex modulation complex demodulation method. Background technique [0002] (1). The modulation and demodulation of the traditional binary frequency shift keying (2FSK) signal is usually implemented by real signal processing. Since the frequency shift keying signal is a band-pass signal, for binary frequencies with the same transmission bandwidth but different center frequencies Shift keying signals need to design different band-pass filters (BPF), so it is more cumbersome to implement. [0003] (2). The digital demodulation of the traditional binary frequency shift keying signal generally adopts non-coherent differential demodulation, and there will be a fractional delay in the demodulation process, that is, the delay of the digital signal cannot be exactly the sampling period (sampling The integer multiple of the reciprocal of the rate), the integer multiple delay of the digital signa...

AI Technical Summary

Problems solved by technology

[0002] (1). The modulation and demodulation of the traditional binary frequency shift keying (2FSK) signal is usually implemented by real signal processing. Since the frequency shift keying signal is a band-pass signal, for binary frequencies with the same transmission bandwidth but different center frequencies Shift keying signal needs to design different band-pass filter (BPF), so it is more cumbersome to implement

[0003] (2). The digital demodulation of the traditional binary frequency shift keying signal generally adopts non-coherent differential demodulation, and there will be a fractional delay in the demodulation process, that is, the delay of the digital signal cannot be exactly the sampling period (sampling The integer multiple of the reciprocal of the rate), the integer multiple delay of the digital signal is very easy to realize, to complete the fractional multiple delay, it must be realized with a single-zero finite impulse response filter (FIR), for different centers The frequency needs to design different single-zero FIR filters. The calculation of the coefficients of this filter is very cumbersome, and the signal processing algorithm is very complicated.

Images