PCM/DPSK/FM modulation and demodulation module and method

Abstract

The invention discloses a PCM / DPSK / FM modulation and demodulation module and method. The module comprises a modulation module and a demodulation module. The modulation module carries out pulse coding modulation on sending information codes, carries out DPSK subcarrier modulation on pulse coding modulation signals and carries out FM modulation on the DPSK modulation signals, thereby finally obtaining double-modulation signals. The demodulation module carries out down-conversion and extraction processing on received signals and carries out FM demodulation on the signals of which rate is reduced, thereby saving hardware resources; the signals output by an FM demodulation module enter a DPSK demodulation module; front and rear code element phase comparison is carried out on the DPSK modulation signals, thereby demodulating modulation information; and finally the DPSK demodulation signals enter a bit timing module, thereby obtaining the optimum judgment point and demodulating the sending information. According to the module and the method, a bit error rate is greatly reduced, and the system performance is improved.

Description

technical field [0001] The invention relates to the field of security control communication, in particular to an FPGA realization method of PCM / DPSK / FM modulation and demodulation. Background technique [0002] With the development of the military, political and economic situation in the international community, the requirements for the security control system are getting higher and higher. Judging from the current security control signals in our country, the rate is usually relatively low, generally in the range of hundreds of bits / second to tens of kilobits / second, and the occupied signal bandwidth is relatively narrow, while the Doppler frequency offset caused by the movement of the spacecraft can maximize the Reaching hundreds of kilohertz has already exceeded the signal bandwidth range. If PSK modulation is used directly, the receiver cannot track and demodulate the signal. Even if some of them use FM / DPSK secondary modulation, most of them are semi-analog and semi-di...

AI Technical Summary

Problems solved by technology

Judging from the current security control signals in our country, the rate is usually relatively low, generally in the range of hundreds of bits / second to tens of kilobits / second, and the occupied signal bandwidth is relatively narrow, while the Doppler frequency offset caused by the movement of the spacecraft can maximize the Reaching hundreds of kilohertz, it has already exceeded the signal bandwidth range

If PSK modulation is used directly, the receiver cannot track and demodulate the signal

Even if some of them use FM / DPSK secondary modulation, most of them are half-analog and half-digital implementation methods. Data processing is difficult and development is difficult.

With the development of the field of security control communication, this modulation system can no longer meet people's needs

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