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polyphase filter amplitude

zxcv2201

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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.
 

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BradtheRad

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Solution

FvM

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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

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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.
 

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