[sdiy] Filter Frequency response measurement ?

[dj hohum]

Hi All,

Is there an easy way to do this that I'm missing? Some sort of
software that generates a sweep and looks at the output?

My understanding of the process is that you use a ramp generator that
sweeps the horizontal of my scope in XY mode and a voltage controlled
sine wave generator at the same time. You feed the sine wave into the
filter and feed the output of the filter into a detector, either peak
or RMS? Then if you feed this into the scope you get a response in
voltage. If you want Db, you need to feed it into a log amp prior to
the scope X input.

Alternatively, can you just feed noise into the filter and take an FFT
of the output?

Surely, there is either software to do this, or, a simple design that
will save me the trouble of piecing it together and calibrating it.
I'm not looking for high quality results, I just want to be able to
tell at a glance what a circuit is doing while I'm working on it.

tnx,
daryl