Design And Simulation Study Of Log-Domain Filters

The Log-domain filter is a new way to settle the problem of linear scope of work of active filter. By the character of current mode and the operation link of Log-Antlog, the filter has some advantage as follows: wilder dynamic range, higher frequency of operation, easier to tune, lower power consumption and noise. It can work at higher request for information processing the occasion.This essay is about the basic formation of Log-Domain filter, analyzing and researching the mathematic model of every part of it. It bases on the second-order LC passive filter and sets up the SFG of the second-order lowpass log-domain filter, which utilizes the calculating simulations. Meanwhile, it completes the parameter calculation of the second-order lowpass log-domain filter by the way of the component substitution, which gets the electrical picture of second-order lowpass log-domain filter. Besides, it simulates the frequency and momentary particularity by the way of Pspice simulation instrument. The result indicates that every parameter satisfies the demand of the design.In reality, the transistor's non-ideal parameters have certain extern influences on the logarithm filter circuit, this article is to the influence of the limited value of , Early voltage, and the base bias resistor Rb, emitter bias resistor RE on the circuit stability and the accuracy conducted a systematic analysis and given a set of reference values by calculating experiment.Finally, according to circuit function and performance requirements, in the case of correct choice of system configuration, circuit form, device structure, Process plan and design rules the second-order low-pass log-domain filter layout.