Distribution method of third-order intermodulation distortion parameter applied inside receiver radio-frequency system circuit

Abstract

The invention discloses a distribution method of third-order intermodulation distortion parameters applied inside a receiver radio-frequency system circuit, which belongs to the technical field of electromagnetic compatibility. The distribution method comprises the following steps: firstly processing the overall receiving performance index of a receiver radio-frequency system according to nonparasitic response to obtain a threshold voltage; then computing the total distortion voltage of third-order intermodulation distortion in each level of sub circuit, which is about to enter a received passband according to constraint relation; and finally obtaining the third-order cut-off point of each level of sub circuit according to the relation that the total distortion voltage is smaller than and equal to the threshold voltage. The method of the invention realizes the distribution of the third-order intermodulation distortion parameters of each level of sub circuit under the condition of cascade circuit voltage signal in-phase, thereby the problem of poor communication quality caused by overlarge third-order intermodulation distortion signal interference of the receiver radio-frequency system is solved.

Description

technical field [0001] The invention relates to a method for allocating third-order intermodulation distortion parameters inside a circuit in a radio frequency system of a receiver. The method solves the interference caused by the third-order intermodulation distortion signal to the receiver, and belongs to the technical field of electromagnetic compatibility. Background technique [0002] The receiver is generally composed of an antenna, a radio frequency system and a demodulation system. The most commonly used superheterodyne receiver radio frequency system includes sub-circuits with nonlinear characteristics such as low noise amplifiers, mixers and intermediate frequency amplifiers. The third-order intermodulation distortion parameter is a very important index of the radio frequency system, and this index determines the power of the generated third-order intermodulation distortion signal. When there are two interfering continuous waves in the receiving adjacent channel, t...

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Problems solved by technology

[0004] The third-order intermodulation distortion signal is a powerful parasitic product that is difficult to filter out, especially when the input signal of the receiver contains two frequencies ω that are close together 1 , ω 2 (Denoted as the front frequency ω 1 , rear frequency ω 2 ), its third-order intermodulation distortion signal frequency Δω(Δω=2ω 1 -ω 2 ) will also be away from ω 1 , ω 2 Close enough to fall within the receive passband, the third-order intermodulation distortion signal usually degrades the communication quality of the receiver

Whether it is the design of the receiver radio frequency system or the simulation evaluation of the communication quality of the receiver system, the overall parameters given by the receiver radio frequency system are often signal-to-noise ratio, total noise figure, bandwidth, dynamic range, gain, etc., without specific The third-order intermodulation distortion parameters of the internal sub-circuit modules of each level

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