Active low pass filter

Abstract

The invention discloses an active low pass filter, which comprises an input matching module, a passive low pass filter module, an inter-stage matching module, a low noise amplifier module and an output matching module, wherein the output end of the input matching module is connected with the input end of the passive low pass filter module; the output end of the passive low pass filter module is connected with the input end of the inter-stage matching module; the output end of the inter-stage matching module is connected with the input end of the low noise amplifier module; the inter-stage matching module enables circuit impedance between the passive low pass filter module and the low noise amplifier module to achieve 50 ohm, and the low noise amplifier module enables the gain of the overall system to be 3 dB larger than the required; and the output end of the low noise amplifier module is connected with the input end of the output matching module. The overall structure comprises the three matching circuit modules, one passive low pass filter module and one low noise amplifier module, the structure is simple and practical, and the active low pass filter can be used in design of other types of filters.

Description

technical field [0001] The invention relates to an active low-pass filter, in particular to an active microstrip ultra-wideband low-pass filter. Background technique [0002] A filter is an electronic device that allows useful frequency signals to pass while suppressing unwanted frequency signals, and is often used in signal processing. Its function is to allow signals from zero to a certain cutoff frequency to pass without attenuation, while suppressing signals at other frequencies. Since there are all kinds of needed or unnecessary information in the real world, it can transform the input signal into the output signal required by the system in a certain prescribed way, allowing some frequency component signals to pass and other signals to pass through. Signals with frequency components are blocked or attenuated. It is a widely used signal processing system, which plays an important role in communication, aerospace, automatic control, sensors and other fields. However, f...

AI Technical Summary

Problems solved by technology

However, for UHF RF filters, the threshold of UHF RF technology is high, the domestic development is relatively late, and the technology is relatively lacking. There are few enterprises engaged in the production of UHF RF products, and there is even a lack of innovative enterprises with independent intellectual property rights.

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