Communication receiver front-end filtering frequency selection method and device

Abstract

The invention provides a front-end filtering frequency selection method and device for a communication receiver, a reference oscillator is arranged and works at a preset frequency, and the preset frequency and a frequency needing to be received can be accurately converted and expressed by a formula; then, the frequency needing to be received is transmitted to a front-end filtering frequency selector, and accurate tuning is achieved; based on the device parameter relationship between the reference oscillator and the front-end filtering frequency-selecting part, the frequency of the front-end filtering frequency-selecting part is just the required tuning frequency. According to the technical scheme, the resonant frequency of the front-end filtering frequency selection part can be accurately and quickly adjusted, the saturation phenomenon of the LNA and the ADC is reduced, the signal-to-noise ratio and the dynamic range are improved, and the receiver performance is improved. And reference signals do not need to be injected in front of the LNA, and continuous mute-free tuning can be realized.

Description

technical field [0001] The present invention relates to the technical field of communication reception, in particular to a method and device for filtering and selecting frequency at the front end of a communication receiver. Background technique [0002] The front-end filter frequency selection of a communication receiver plays an important role in the overall performance of the receiver. A well-designed front-end frequency selection can effectively remove unwanted radio interference components, improve signal quality and system dynamic performance. [0003] In heterodyne or superheterodyne receivers, an LC resonant front-end frequency selection loop is generally used, usually two variable capacitors or two varactor diodes are used, and the characteristic frequency of the LC loop and the oscillation frequency of the local oscillator are changed at the same time. Keep the difference (that is, the intermediate frequency) constant, and then process the intermediate frequency s...

AI Technical Summary

Problems solved by technology

The benefits are obvious, but there are also some problems. For example, due to the lack of front-end resonance frequency selection filtering, it may cause the front-end signal bandwidth to be too wide, signal blocking, insufficient dynamic performance, and limited selectivity, etc.

[0005] U.S. Patent 7127217 proposes a method to realize the frequency selection method of the front-end filter of the low-IF receiver. The main idea is the signal injection tuning method. Although accurate LC resonance front-end filter frequency selection can be realized, since the signal needs to be injected every time the frequency is changed, Therefore, it is impossible to achieve continuous output signals, and it needs to be muted when tuning, otherwise the output is a local injection signal

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