Abstract: We presented a circuit structure and realization me thod of the currentcontrolled selftracking filter which based on the design of LC ladder network. The input voltage signal was firstly processed by the amp lifying circuit, and then the frequency selftracking circuit was composed of a mplitude limiting circuit, shaping circuit and bro adband frequencycurrent conversion circuit. The amplified voltage signal was c onverted into the current signal which was used as the bias current control end of the log domain filter circuit to adjust the cutoff freq uency or central frequency of the filter. Therefore, frequency of the fi lter could automatically track the input signal frequency. Simulation experiment results show that the highest central frequency of the bandpass filter and lowpass filter is 30 MHz, and the tracking ra nge of input frequency is from 1 MHz to 30 MHz. Simulation results verify the effectiveness and feasibility of the proposed method.

Key words: selftracking, broadband frequencycurrent conversion circuit, logdomain filter, selftracking filter