Biquad active rc filter circuit and its compensation method

Abstract

The invention relates to a double-second-order active RC filter circuit and a compensation method thereof. The circuit comprises an Akerberg-Mossberg double-second-order unit and a resistor R5, wherein one end of the resistor R5 is connected with the inverted input end of an operational amplifier A1 of the Akerberg-Mossberg double-second-order unit, and the other end of the resistor R5 is connected with the output end of an operational amplifier A3 of the Akerberg-Mossberg double-second-order unit. According to the double-second-order active RC filter circuit and the compensation method thereof, the double-second-order active filter circuit with a high Q value is built by using the operational amplifiers with low gain bandwidth products, sensitiveness to the gain bandwidth products of the operational amplifiers of the Q value is minimized, and power consumption of a filter is reduced. An active feedback network is built by means of an existing reverse buffer, leading phase quantity matched with the gain bandwidth products of the operational amplifiers is provided, and the best phase compensation is conducted on consumption of two integrators of a feed-forward network in a frequency range of a filter transmission band.

Description

Technical field [0001] The present invention relates to filter technology. Background technique [0002] The biquad unit is the basic component of the active RC filter. The low-pass biquad unit has the following transfer function circuit, [0003] [0004] Among them: the center frequency is ω0, the quality factor is Q, and the DC gain is H. [0005] The filter is a commonly used electronic component, and the filter processes the amplitude or phase of the signal based on the frequency. Mathematically, the ripple characteristic and phase characteristic of the filter are constrained in advance, and various filter types such as Butterworth filter, Chebyshev filter, Bessel filter, elliptic filter, etc. can be obtained. High-order large-bandwidth filters are common in channel selection filters of communication equipment. The high-order filter can be realized by cascading multiple biquad units. The high-order large bandwidth filter formed by cascading biquad units includes at least on...

AI Technical Summary

Problems solved by technology

[0019] One of the purposes of the present invention is to propose a biquad active RC filter circuit, which can solve the problem of uncontrollable lead phase

[0020] The second object of the present invention is to propose a compensation method for a biquad active RC filter circuit, which can solve the problem of insufficient or excessive compensation

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