Fast Digital Gain Conversion Circuit of Missile Preamplifier

Abstract

The invention belongs to the missile circuit technology, and relates to the improvement of the missile preamplifier. It includes a missile-borne computer and a low-noise operational amplifier U2, and is characterized in that there is a digital analog switch U1 whose output terminal Out is connected to the inverting input terminal of the low-noise operational amplifier U2, and its positive power supply terminal Vdd and negative power supply The terminal Vss is respectively connected with the positive and negative power supplies, its address data input terminal Adr is connected with the corresponding output port of the bomb computer, its signal input terminal is respectively connected with one end of the input resistor, and the other end of the input resistor is connected with the signal input of the conversion circuit. terminal Vin connection. The invention cancels the capacitance in the feedback loop, greatly shortens the response time of gain switching, and improves the tracking stability of the missile.

Description

Fast Digital Gain Conversion Circuit of Missile Preamplifier technical field The invention belongs to missile circuit technology and relates to the improvement of the missile preamplifier. Background technique The preamplifier is an important part of the infrared air-to-air missile. It not only requires low noise to amplify the weak signal input by the infrared detector, but also must change its own magnification according to the size of the front-end signal to send the signal to the information processing without distortion. system. The gain conversion circuit in the preamplifier of a certain domestic missile is shown in Figure 1. The feedback network of operational amplifier U1 is composed of resistor R1, resistor R4, resistor R5, capacitor C1 and field effect transistor U3. Field effect transistor U3 is used to change the magnification. Due to the influence of capacitor C1 in the loop, its response time is very long. It takes tens of milliseconds to give a normal ampl...

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Problems solved by technology

the missile risks losing its target if there is a sudden chan

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