Filter Design Software

An XOR phase detector is like a comparator -> +/-1 opamp lockin?

George (just checking) Herold

Just an XOR gate followed by an RC or active filter. Assuming the duty cycles are 50%, When one signal goes away, the average value of the PD output doesn't move.

Diode bridge mixers and analogue multipliers are better, since they don't have the big offset voltage or the duty cycle dependence.

Cheers

Phil Hobbs

I think you mean "half-lattice," not "mesh." Sometimes half-lattice is ref erred to as a "semilattice." Inductance between the lattice sections will allow bandwidths of tenths of a percent to above 5%. When shunt, the induct ors can also perform as transformers. This can (1) change impedance levels and (2) realize the half-lattice.

See ch.4 of Modern Filter Theory and Design on crystal filters (Temes-Mitra , but chapter by Szentirmai). Szentirmai's Filsyn has been released to the public. Also, Kinsman's book gets referenced a lot.

This is definitely crystal filter territory. Both Vectron and MtronPTI mak e custom crystal filters, for example.