Demodulation algorithm for signals in radio frequency direct acquisition

Abstract

The invention discloses a demodulation algorithm for signals in radio frequency direct sampling, which comprises the following steps of: designing a multiphase local oscillator in an FPGA (Field Programmable Gate Array), carrying out multiphase frequency mixing on the multiphase local oscillator and a sampling signal, and carrying out extraction and low-pass filtering processing to realize digital demodulation so as to obtain a baseband signal; the method has the beneficial effects that under the implementation of the algorithm, a local oscillation source, a frequency mixing circuit, a first intermediate-frequency filter circuit, a second intermediate-frequency filter circuit, a medium-frequency amplifying circuit and the like are omitted in a receiving channel, so that the size of the receiving channel is greatly reduced; due to the design of small size and light weight, the TACAN airborne equipment can be installed on certain types with limited weight and size; after most of devices of receiving channels are omitted, the hardware cost is greatly reduced; in the algorithm, the signal bandwidth is realized through the design of a digital filter, and in order to adapt to the DME / P and ADS-B functions, only the bandwidth of a low-pass filter in software needs to be changed.

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