I constructed a notch filter for use in an ECG and am having trouble with it. It works well except for the fact that there is 60 hz hum at the output of the notch filter (ironic). It attenuates the correct frequencies that are put in at the input, however there is a constant 60 hz signal at the output as soon as the +/- 3v power supplies are turned on for the op amps. Im using the twin T adjustable Q configuration with 2 op amps found in the following link.
http://www.national.com/ms/LB/LB-5.pdf
I tried placing two 47 uF caps across each power supply but that didn't do anything. Does anyone else have any suggestions?
http://www.national.com/ms/LB/LB-5.pdf
I tried placing two 47 uF caps across each power supply but that didn't do anything. Does anyone else have any suggestions?