Digital all-pass filter design method based on hybrid particle swarm algorithm

Abstract

The invention discloses a digital all-pass filter design method based on a hybrid particle swarm algorithm, which comprises the following steps: constructing a phase-frequency response of the digitalall-pass filter based on second-order cascade connection according to design requirements; then based on target phase-frequency response, building a cost function via an error value between the phase-frequency response of the digital all-pass filter and the target phase-frequency response; and finally, searching a global optimal solution in a value domain range by using a global search particle swarm algorithm to obtain a rough solution, and triggering accurate search performed by using a Levenberg Marquardt algorithm from the rough solution, thereby optimizing the positions of poles of all second-order all-pass filters, so that the mean square error minimization of the designed all-pass filter phase frequency response and the target phase frequency response is realized, and the design ofthe filter coefficient is realized.

Description

technical field [0001] The invention belongs to the technical field of all-pass filters, and more specifically relates to a design method of a digital all-pass filter based on a hybrid particle swarm algorithm. Background technique [0002] In practice, when the signal is transmitted in the system, it will produce a certain phase distortion, especially the nonlinear distortion of the phase, which will add different phase shifts to the signals of different frequencies, which will have a greater impact on the output of the system, seriously signal will be distorted. Therefore, for systems that require strict linearity in the phase, compensation for the phase is an essential part. The all-pass filter can change the phase characteristics of the signal, which can effectively solve the problem of phase nonlinear distortion. The all-pass filter has the same gain for all frequency components input in the system, and does not attenuate any frequency signal, but will change the phas...

AI Technical Summary

Problems solved by technology

However, in the optimization process of designing digital all-pass filter by PSO algorithm, the optimization speed will decrease obviously after approaching the global optimal solution, and even premature phenomenon will occur.

The LM algorithm is an unconstrained optimization problem. Although it has a fast optimization speed, but because the optimization range is not limited, it is easy to cause the design of the digital all-pass filter to be unstable. In addition, this type of algorithm Very sensitive to the initial value of the optimization iteration

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