polyphase filter amplitude

[zxcv2201]

I'm trying to configure a polyphase filter using cadence to make a 4 phase output. Between each output phase, the phase difference is 90 degrees, but the amplitude is not the same. How can I make the amplitudes the same? Can you make the same amplitude by sweeping the C and R values? Please let me know if there is any paper on this subject.

 

[BradtheRad]

Your results demonstrate that greater phase shift is related to greater attenuation of signal.

By adding more components (thus making a more complex network) you can achieve 4 identical amplitudes.
See related Edaboard discussions:

www.edaboard.com/threads/phase-shifter-circuit.389898/

www.edaboard.com/threads/audio-i-q-phasing-networks-which-is-better.354456/

Also check the list of related thread titles further down this column.

 

[FvM]

Complex RC ladder networks are used to implement quadrature phase shift over a wider frequency range, e.g. 300 Hz to 3 kHz speech. Here's the design by Llyod Butler mentioned in previous thread http://users.tpg.com.au/ldbutler/SSBModulator.htm

As discussed previously, the filters implement an approximation with some phase ripple. The more stages you spend, the lower the ripple.

For single frequency, there's no need to use a complex network, just tune RC values.

 

[frankrose]

For a single frequency with #1 post circuit if R1=R2=R, C1=C2=C and R*C=1/(2*pi*f) you will get the same amplitudes.