Quote:
Originally Posted by nemo_07
If you dispense with benefits of critical or sub-critical coupling, there is a point where a question arises whether a coupled BP still makes much sense.
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If you've got a chain of amplifiers with a chain of resonators, you don't necessarily treat pairs of coupled resonators individually, You might position their poles so that the complete RF chain creates a classical filter prototype like Butterworth or Bessel. I'm assuming you wouldn't want Chebyshev because of the large group delay excursions.
With good resonator design multi-section VHF/FM front ends can be a little narrow for the occupied channel bandwidth in terms of phase flatness. I have one Sony flagship tuner which uses a fast signal from the discriminator to make the RF tuned stages follow the modulated signal, flattening phase variation.
Once, gain was expensive. Now it's cheap, but selectivity and screening remain expensive.
David