Low-noise amplifying system with constant noise and linear phase during programmable attenuation

Abstract

The invention discloses a low-noise amplifying system with constant noise and a linear phase during programmable attenuation. A first bilateral switch, an attenuating and compensating module, a second bilateral switch and a low noise amplifier are connected in sequence between an input end and an output end of the system. The system also comprises an adaptive digital programmable attenuation control module, wherein the adaptive digital programmable attenuation control module is applied to digital programmed control of amplitude attenuation, and used for performing signal channel adaptive control according to digital attenuation at the same time in order that a programmable attenuator keeps a system noise level constant in the presence of attenuation and keeps low insertion loss of a signal channel in the absence of attenuation, and the influence of the insertion loss of a programmable attenuation radio-frequency electronic switch on a system noise coefficient is lowered; the attenuating and compensating module is used for attenuating a signal amplitude, and compensating for an electric length of a signal phase during signal attenuation through the radio-frequency electronic switch by calculation of a frequency wavelength in order to obtain the same phase difference under different attenuation situations and compensate for phase deviations caused by programmable attenuation; and the low noise amplifier is used for realizing low noise amplification of signals.

Description

technical field [0001] The invention belongs to the field of radar communication, and relates to a low-noise amplification system, in particular to a low-noise amplification system with constant noise and linear phase during program-controlled attenuation. Background technique [0002] The low noise amplification system is an important part of the air traffic control radar system, which is mainly used for low noise reception of radar echoes. The noise figure index of the low noise amplification system determines the detection power of the radar equipment. The noise figure is defined as figure 1 shown. The attenuation setting and linear phase characteristic of the programmable attenuator determine the detection performance of the radar equipment. The design technology of low noise amplification system affects the detection performance of radar equipment to a great extent. In the development of traditional radar equipment, the programmable attenuator is placed after the l...

AI Technical Summary

Problems solved by technology

If this program-controlled attenuator is directly prepended to the low-noise amplifier, according to the definition of the noise figure, the noise figure of the low-noise amplification system will increase by 1dB

[0004] In addition, when the program-controlled attenuation is performed on the receiving channel, the phase of the signal channel is not processed. According to the analysis, the phase deviation caused by the program-controlled attenuation will cause the pulse compression sidelobe of the wide pulse signal, which will affect the detection performance of the radar equipment.

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