Max264 Program-controlled Low-pass Filter Design,

The ordinary hardware active filter are composed by the operational amplifier and resistance,capacitance, though it is quite easy to realize, but it is difficulty to adjustment the parameter, moreover when the working frequency is high, around the element's stray capacitance will seriously influence the filter's characteristic and deviate the predetermined working conditions, and the ultimate effect is not very well. MAXIM company has introduced a single-chip integrated filtering MAX264 chip is a relatively ideal present on the chip.This design introduces the design based on the the MAX264 chip programmable low-pass filter design, it describes the composition of the system, the principle, the hardware design and the way of programming. In addition,using the SCM as the core control to use of program-controlled to achieve a low-pass filtering, including changes the Q and N-value or changes the clock value of the input clock signal to achieve it. Explains how to choose a model, as well as in different model's how to set the frequency coding mode input and Q values encoded input. Summes up the designe's advantages, in particular points out the problem should pay attention in practical application. And on the basis of theoretical calculations, designed by MAX264 achieve cutoff frequency of the low-pass filter cutoff frequency -3 dB in the 1 kHz to 20kHz within adjustable filter circuit. Through the further laboratory tests proves the MAX264 filter filtering effect.