I have an 8-element MW active array (DA100E's and ALA1530's) spread out
over the yard and combined in 7 ANC-4's

I need a way to put a slight phase shift and amplitude shift on
one (or more) of the inputs, because when you're down in a 60dB
null, fraction-of-hair turns of the ANC-4 pots become necessary.

At the moment, I add another ANC-4 to another element at very very low
gain and use it as the final trim, but that produces a 3dB loss in
signal too.

So I want a passive box on one of the inputs instead, where turning
a couple of knobs will produce a _slight_ shift in phase and in
amplitude (they can couple but have to have two degrees of freedom).

I was thinking of a capacitor in series, and a pot voltage divider
selecting the main output and a tiny bit of the capacitor output,
for one; a straight voltage divider pot for the other. Pots in
parallel with small resistors to make them have very little effect.

Then, I was thinking, I could get close to a null with the ANC-4's,
and then finalize it with the trimmers.

Any suggestions? Better ideas?
--
Ron Hardin


On the internet, nobody knows you're a jerk.