Middle frequency receiving circuit and receiving method

Abstract

The present invention discloses an intermediate frequency receiver circuit including: a inductance capacitance resonance circuit the primary resonance frequency of which is the intermediate frequency of the received signal for receiving the intermediate frequency signals and restraining the transmitting signals and control signals; a band-pass filter connected to the inductance capacitance resonance circuit for filtering the transmitted signals and control signals; an automatic gain control circuit connected to the band-pass filter for compensating the attenuation of the intermediate frequency cable; a lowpass connected to the automatic gain control circuit for compensating in-band flatness; a analog-to-digital converter connected to the lowpass for performing received signal sampling and data modulation. The present invention also discloses an intermediate frequency receiving method. The intermediate frequency receiver circuit can provide excellent intermediate frequency receiving channel norm, improve the in-band flatness and reflectance, increasing the degree of straining the transmitting intermediate frequency signals and low frequency control signals, thus, the receiving sensitivity of the system is improved and the in-band consumption is reduced, and a variable gain can also be provided.

Description

technical field [0001] The invention relates to a receiving technology of a microwave system, in particular to an intermediate frequency receiving circuit and a receiving method, belonging to the technical field of communication. Background technique [0002] As shown in Figure 1, in a microwave system, the indoor unit and the outdoor unit are usually installed separately, and the two are connected by an intermediate frequency cable, which is used to transmit and receive intermediate frequency signals and control signals and provide power. For large-capacity microwave systems, the performance index of the intermediate frequency receiving circuit directly affects the system sensitivity, so the importance of the intermediate frequency receiving circuit is obvious. [0003] The key indicators of the IF receiving circuit include: reflection coefficient, in-band flatness, suppression of transmitted signals and control signals, dynamic range and group delay characteristics, etc. ...

AI Technical Summary

Problems solved by technology

In the case of broadband, the existing IF receiving circuit has broadband characteristics due to the input impedance of the amplifier and the influence of the IF port protection circuit. It is difficult to improve the reflection coefficient of the filter, and at the same time, the dispersion is relatively large

For example, the port reflection coefficient of the existing IF receiving circuit is generally -15dB

[0008] 3. The receiving sensitivity of the system is not high

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