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Measurements >> Phase Noise and Jitter Measurements >> PLL Based Frequency Synthesizers
https://designers-guide.org/forum/YaBB.pl?num=1075267010

Message started by atharapi on Jan 27^th, 2004, 9:16pm

Title: PLL Based Frequency Synthesizers
Post by atharapi on Jan 27^th, 2004, 9:16pm

Hello,

I am doing a frequency synthesizer design in Cadence and am just starting out.

What are the best resources to figure out how to measure phase noise of the entire synthesizer, using Cadence ? Does one use Spectre ? HSpice ? How does one get started ?

Any help would be appreciated.

Title: Re: PLL Based Frequency Synthesizers
Post by August West on Jan 28^th, 2004, 2:24pm

If you are interested in the effect of device noise on the phase noise, SpectreRF is essential. HSPICE is not capable of doing a noise analysis when large signals are present and so in this case is worthless. Even if you are interested in studying the effect of noise coupling, either through the supplies or through the substrate, SpectreRF is the best choice because it provides the PAC/PXF small-signal analyses that can compute the transfer functions of circuits in the presence of large signals. So you would compute the output noise by multiplying the input noise by the transfer function.

For coupling, it is also possible to do brute-force transient simulation, in which case HSPICE could be used, but Spectre would be a better choice. It is very tough to control errors in HSPICE, and this particular simulation would have to be performed with the errors carefully controlled because the interferring signals are small.

For a reference, try http://www.designers-guide.com/Analysis/PLLnoise+jitter.pdf. It is long, but it has a lot of information.

-August