James D. Duffer wrote:
>
> Dr. Gerald N. Johnson, P.E. wrote:
> >
> > Its not true that a twin-tee notch filter in the feedback will cause
> > greater reduction in the noise at the notch frequency. Quite the
> > contrary, a twin-tee notch filter in the feedback makes a bandpass
> > amplifier. At least 4 decades ago, maybe 6, General Radio based an audio
> > spectrum analyzer (manual type) on a twin-tee feedback network and an
> > amplifier.
> >
> > Oh, it takes three R and three C to make a twin tee network.
> >
> > 73, Jerry, K0CQ
>
> Wouldn't it make a difference if the twin-tee was included in
> degenerative vs a regenerative feedback. I would think it would make a
> big difference. In the above context, what kind of feedback? Just
> wondering??
>
> 73,
>
> Jim WD4AIR (FAA Retired)
One hardly ever finds regenerative feedback as a feature of an audio
stage....
73, Jerry, K0CQ
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