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Idealized Baseband Filters

This model shows how to use Bandpass RF Filter blocks from the RF Blockset™ Idealized Baseband library to compare two Chebyshev I filters of order 3 and 5 with passband ripple of 1 dB.

Example Model

Filter specifications: Center frequency = 75 MHz, Lower passband edge frequency = 72 MHz and Upper passband edge frequency = 78 MHz. Based on these parameters, the bandwidth of the filter at -1 dB = (78-72) = 6 MHz.

Fig. 1 Idealized Baseband filter example model:

Simulation Results

The following figure shows the equivalent baseband frequency response of the filter from 70 MHz (-0.5 MHz) to 80 MHz (0.5 MHz). As expected, the frequency response of the 5th order filter has five ripples and the frequency response of the 3rd order filter has three ripples. Also, the roll-off of the 5th order filter is steeper than the roll-off of the 3rd order filter.

Fig. 2 Filter frequency responses:

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