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Modeling of Arbitrary Phase Shift in Verilog-A (Read 6325 times)
samiran
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Modeling of Arbitrary Phase Shift in Verilog-A
Jun 22nd, 2010, 10:41pm
 
Dear All,

I want to write a verilog-A code which provides an arbitrary phase shift (which can be controlled as a parameter) of the actual o/p signal.

Is there any in-built function already available to do so? If not, how can I achieve this?

Regards
Sam.
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pancho_hideboo
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Re: Modeling of Arbitrary Phase Shift in Verilog-A
Reply #1 - Jun 24th, 2010, 7:26am
 
samiran wrote on Jun 22nd, 2010, 10:41pm:
Is there any in-built function already available to do so?
No.

samiran wrote on Jun 22nd, 2010, 10:41pm:
If not, how can I achieve this?
Synthesize aribitrary phase shifter using cascaded connected All-pass Filters.

http://en.wikipedia.org/wiki/All-pass_filter

Also see http://www.designers-guide.org/Forum/YaBB.pl?num=1233062253/1#1
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Ken Kundert
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Re: Modeling of Arbitrary Phase Shift in Verilog-A
Reply #2 - Jun 24th, 2010, 11:28am
 
You could use the absdelay() function. Unfortunately, Cadence's implementation does not work in the small-signal analyses. It has been that way for 14 years, so I guess they are not going to fix it.

It might help if you explained what you are trying to do. Verilog-A is a hardware description language, so it might help you to think about how you would implement this in hardware.

-Ken
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pancho_hideboo
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Re: Modeling of Arbitrary Phase Shift in Verilog-A
Reply #3 - Jun 24th, 2010, 11:38am
 
Ken Kundert wrote on Jun 24th, 2010, 11:28am:
You could use the absdelay() function.
I don't think absdelay() can be used as phase shifter.

Transfer function of absdelay() is exp(-j*ω*Tdelay).
So you can get only phase shift which changes linearly with frequency.
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« Last Edit: Jun 25th, 2010, 4:05am by pancho_hideboo »  
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