Broadband low-noise high-linearity wide-range demodulation system

Abstract

The invention discloses a broadband low-noise high-linearity wide-range demodulation system, and relates to the technical field of broadband demodulation. The system comprises a receiving unit and a transmitting unit, the receiving unit comprises a low-noise amplification module, the low-noise amplification module is connected with a voltage-current conversion module, the voltage-current conversion module is connected with two down-conversion modules, the down-conversion modules are connected with a transimpedance amplification module, the transimpedance amplification module is connected with a first low-pass filtering module, and the first low-pass filtering module is connected with a second low-pass filtering module. The first low-pass filtering module is connected with a variable gain amplification module, the variable gain amplification module is connected with analog-to-digital conversion modules, the two analog-to-digital conversion modules are connected with a first integrated unit, and the transmitting unit comprises a resistor. The low-pass filter is closely followed after the transimpedance amplification module, so that out-of-band blocking is further suppressed, the pressure of the analog-to-digital converter is reduced, the bandwidth of the filter can be accurately calibrated, and controllable current is injected into the input side of the variable gain amplification module.

Description

technical field [0001] The invention belongs to the technical field of broadband demodulation, in particular to a broadband low-noise high-linearity wide-range demodulation system. Background technique [0002] The main function of the receiver is to select the frequency components you need from the many electromagnetic waves in the air, suppress or filter out unnecessary signals or noise and interference signals, and then obtain the original useful information through amplification and demodulation. Ideal The receiver suppresses all unwanted noise, including other signals, and does not add any noise or interference to the desired signal. Regardless of the form or format of the signal, it can be transformed to suit the characteristics required by the signal processor's detection circuit. Then it is sent to the intelligent user interface, and the main task of the transmitter is to complete the modulation of the useful low-frequency signal to the high-frequency carrier, and co...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a wide-band low-noise high-linear wide-range demodulation system, which solves the problem of existing receivers. From the perspective of system indicators, in order to achieve a better overall noise figure for reception, high gain of low-noise amplification is required. It is high enough, but to achieve wide range and high adjustment precision AGC, the low-noise amplification gain range is required to be wide enough and fine enough; for the transmitter, since the RF amplifier module works in a state of large signal and high power, it is usually nonlinear in the system Dominant, for broadband systems, the linearity is further deteriorated, and new technical problems such as in-band unevenness and broadband matching will be introduced

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