Got an intersting problem:
inputs: sine wave, 50 to 500 Hz, 10 volts p-p, 50 ohms, and its 180 degree opposite.
Outputs: two sine waves, 90 degrees apart, within 2% in phase, 20% in amplitude. Working into a 100K ohm load, at least 2v p-p.
Catch: has to be done with just r's and c's, no active components.
I see lots of phase-shifters that use op-amps, or work at one frequency, or work from 300-3000 Hz, but nothing in the range I need.
Any hints appreciated.