Ladder Filters

This model shows how to use LC Bandpass Tee blocks from the SimRF™ Equivalent Baseband library to create two Chebyshev I filters with passband ripples of 1 dB and 0.1 dB.

Example Model

Filter specifications: Center frequency = 75 MHz, Source impedance = 0.01 ohms and Load impedance = 1e5 ohms.

Fig. 1 Ladder filters example model:

Simulation Results

The following figure shows the equivalent baseband frequency response of the filter from 70 MHz (-5 MHz) to 80 MHz (5 MHz). It illustrates passband ripple design and the effects of filter order on roll off.

Fig. 2 Filter frequency responses:

Reference

Chris Bowick, RF Circuit Design, Indianapolis: H.W. Sams, 1982.

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