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Simulators >> Circuit Simulators >> burst source
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Message started by ic_engr on Feb 8^th, 2010, 11:52am

Title: burst source
Post by ic_engr on Feb 8^th, 2010, 11:52am

I need to use a burst sine wave. Basically a sine signal with abitlity to repeat with a burst frequency.

Any Ideas.

ic_engr

Title: Re: burst source
Post by Andrew Beckett on Feb 9^th, 2010, 3:38am

Not sure I understand what you're asking. Perhaps a picture or reference might help?

What varies over time? A sine wave is normally repeating, so I'm not sure what the "burst frequency" is for - what does it actually change?

This might be a well known term, but it's not well known to me!

Regards,

Andrew.

Title: Re: burst source
Post by ic_engr on Feb 9^th, 2010, 5:16am

What I need as a sourse is a periodic sine signal which turns on and off at a specific rate. For example, a 100Hz sine wave that starts at 1msec and then after few cycles of 100Hz turns-off and then repeats.

I may be able to do this using switches but was hoping to get something more generic from the sources available may be even in ahdl.

ic_engr

Title: Re: burst source
Post by pancho_hideboo on Feb 9^th, 2010, 5:33am

ic_engr wrote on Feb 8^th, 2010, 11:52am:

I need to use a burst sine wave. Basically a sine signal with abitlity to repeat with a burst frequency.

Use the following.
http://edocs.soco.agilent.com/display/ads2009/VtRF+Pulse+%28Voltage+Source%2C+RF+Pulse%29

Title: Re: burst source
Post by ic_engr on Feb 9^th, 2010, 5:51am

Hello pancho_hideboo,

I donot see this source is Cadence analogLib nor in ahdlLib. Any suggestions.

ic_engr

Title: Re: burst source
Post by pancho_hideboo on Feb 9^th, 2010, 5:57am

The followings are general notes.

- Always describe vendor's name which you use as tool or simulator.
- There are many simulators which have analyses called as PSS, PAC and Pnoise.
- Describe in detail with using correct terminologies.
- Warnigns are different from Errors.
- ADS is not name of simulator.
- There is no tool which name is Cadence.
- Don't use Direct Plot of Cadence ADE blindly without knowing definition.
- All gains in Direct Plot of Cadence ADE are "right", "true" and "practical" voltage gain.
- Don't mix up Simulation with Post Processing. They are completely different phase.
- MATLAB are different from Simulink.
- Learn measurements using actual instruments. Not "EDA Tool Play

ic_engr wrote on Feb 9^th, 2010, 5:51am:

I donot see this source is Cadence analogLib nor in ahdlLib.

This source is available in adsLib for Cadence DFII.

If you don't have Agilent RFDE, you have to create custom source by Verilog-A.
I can easily create custom source which realize same function as "VtRF_Pulse" in "adsLib" by Verilog-A.

Burst sinusoidal is no more than ASK or OOK signal.
So if you don't have skill to write custom source by Verilog-A, use combination of vsin, vpulse and multiplier.

Title: Re: burst source
Post by Andrew Beckett on Feb 9^th, 2010, 6:18am

This is easy enough to do in spectre without needing VerilogA.

Create an instance of vsource set to sine, or vsin - e.g. I had frequency 1M, ampl 2
Create an instance of vsource set to pulse, or vpulse which is your burst - for example, period 10u, width 5u, rise/fall 1n, low voltage 0, high voltage 1.
Create an instance of pvcvsp with number of controlling voltage set to 2, Max coefficent number set to 4, and set Poly Coeff 0-3 to be 0, and Poly Coeff 4 to be 1.
Wire all the - pins of the pvcvsp instance to ground, and the + input pins to the two sources - the output pin will be your "burst" sine source.

This works by utilizing spectre's "pvcvs" (polynomial voltage controlled voltage source) - type "spectre -h pvcvs" for more details. The coefficients are chosen so you only get the product of the two input sources.

Regards,

Andrew.

Title: Re: burst source
Post by ic_engr on Feb 9^th, 2010, 6:20am

Well I do not see adslib, I see rfLib in Cadence dfII.

ic_engr

Title: Re: burst source
Post by ic_engr on Feb 9^th, 2010, 6:21am

Andrew,

Thanks for your input, I will try it.

ic_engr

Title: Re: burst source
Post by Andrew Beckett on Feb 9^th, 2010, 6:22am

adsLib comes with the Agilent tools (e.g. RFDE), and is for Agilent simulators.

If you're using spectre, you can use the suggestion I made previously.

Regards,

Andrew.

Title: Re: burst source
Post by ic_engr on Feb 11^th, 2010, 4:53am

Andrew,

Thanks you suggestion worked perfectly well with polynomical vcvs.

ic_engr