Multi-channel digital down-conversion device

Abstract

The invention discloses a multi-channel digital down-conversion device, which comprises a signal acquisition module, an m*n-way switch matrix, a digital down-conversion module and an FPGA controller. Firstly, the FPGA controller controls the digital down-conversion module and determines the working mode of the digital down-conversion module, such as a narrow-band parallel mode, an orthogonal joint mode and an orthogonal alternative joint mode; secondly, the FPGA controller controls the input / output connection state of the m*n-way switch matrix to further finish the paired connection between an m-channel signal acquisition channel and a digital down-conversion channel so as to carry out demodulation according to different down-conversion working modes; and thirdly, the FPGA controller controls each digital down-converter and writes the index parameters of a numerical control oscillator, the index parameters of a digital extractor and the index parameters of a low-pass filter into corresponding internal registers so that each digital down-converter can be independently programmed. The digital down-conversion device of the invention can realize digital down-conversion processing of various band widths and various index parameters for multiple-channel digital intermediate-frequency signals, ensuring better real-time performance.

Description

technical field [0001] The invention belongs to the technical field of digital down-conversion, and more specifically relates to a device for performing digital down-conversion processing on a plurality of analog intermediate frequency signals. Background technique [0002] After the analog intermediate frequency signal is sampled by an analog-to-digital converter (ADC), the resulting digital intermediate frequency signal must be moved to the baseband. This moving process is the so-called digital down-conversion technology. The digital down-conversion process includes quadrature demodulation, digital decimation and low-pass filtering. [0003] figure 1 It is the specific implementation block diagram of the digital down converter. Such as figure 1 As shown, the digital down-converter is mainly composed of a numerically controlled oscillator NCO, a digital decimator and a low-pass filter. The digital down-converter performs quadrature mixing on the sampling data obtained b...

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Problems solved by technology

like figure 2 As shown, each signal acquisition channel can only be connected to a fixed digital down-conversion channel, and each digital down-conversion channel is independent of each other, and the working mode is relatively single. Due to the comparison of the functional structure of this multi-channel digital down-conversion device Therefore, when receiving a burst or sporadic unknown signal, it is necessary to store the signal for a certain period of time, and then try multiple times of digital down-conversion processing to obtain more parameter information to determine the unknown signal. The real-time processing ability of this device is very weak, and the effect is not good

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