In this lab we will use the Linear Technology LTC1060 (almost
the same as the Maxim MF10) Universal Dual Switched-Capacitor
Filter to implement a 4-pole bandpass filter. As usual, it will
be advantageous to start the filter design before coming to lab.
NOTE: The LTC1060 has a maximum supply voltage of +/- 8 V. Operate
the chip at +/- 5 V.
1) Design a 4-pole bandpass filter with, having a Q of 25, a center
frequency of 2 kHz, and a gain in the pass band of 1. Use the
configuration of Mode 3 of the filter, which is useful for cascading.
2) Build the 4th order filter by cascading two 2nd-order bandpass
filters built using Mode 3 of the LTC1060.
3) The first filter block has a low-pass, high-pass and band-pass
output. Verify the operation of these three outputs for frequency
inputs in the range of 0 to 20 kHz. Now look at the outputs for
frequencies around 200 kHz, 400 kHz, etc.
4) Measure the frequency response, gain and bandwidth of the 4-pole
bandpass filter and compare with the desired values. Plot amplitude
and phase. What happens to the phase as you go through the passband?
5) Change the center frequency to 1~kHz by changing the clock
frequency. What should the bandwidth of the filter be now?