Notch filter

A special form of active filtering can be thought of as the reverse of bandpass filtering. In analyzing a

notch filter

we concentrate on the noise rather than the signal.

$\parbox{2.0in}{\raisebox{-1.5in}{\par \hbox{\hskip 0in \vbox to 1.5in{\includegraphics[height=1.5in]{FIGS/fig5.3.ps}\vfill}}}}$ $\parbox{3.0in}{% AF100 has one additional, uncommitted, summing op-... ...ou disconnect the grounding wire from pin 3!} Set the AF100 to $f_0 = 500$Hz. }$

Measure the frequency response of the notch filter. Choose the frequencies of the FG wisely: take a sufficient number of measurements to resolve the shape of the filter's transfer function.

Plot the gain vs. log frequency.

What type of noise could be reduced using the notch filter?

Determine $f_0$ from your plot. How does it compare with the expected value?