Hi all,

I have two questions about pnoise jitter calculation in SpectreRF.

__1. What is the meaning of Freq. Multiplier in jitter calculator?__

__2. What is the optimum integration range of phase noise for jitter calculation?__

Actually, I posted about similar subject last year, but I'm still confused..... : (

I need to calculate VCO's jitter to estimate the SNR limit of synchronous ADC by clock.

I've done PSS/PNOISE simulation like following condtion

- Free running VCO

- VCO clock speed : 10MS/s

- Total ADC conversion time : 100us(1000cycle)

- PSS

Beat frequency : 10MHz

Output harmonics(Number of harmonics) : 0

- PNOISE

Output Frequency Sweep Range : 1~500MHz(I have no idea what's the right sweep range. I just think it would be wide enough)

Maximum Sideband : 40(40 is enough to get accurate results in my case)

Noise type : Jitter(Typically, ADC needs only RMS jitter, not phase noise)

After PSS/PNOISE simulation, I caculated k-cycle jitter because the VCO is autonomous system and I need accumulated RMS jitter.

Following is what I did.

Results->Direct Plot->Main Form->select pnoise jitter(Analysis)->Jc(Function)->Number of cycles=1000->select RMS->

->Freq. Multiplier=1->Integration Limits:1kHz~20MHz

Here are two questions as I asked above.

__1. What is the meaning of Freq. Multiplier in jitter calculator?__

__2. What is the optimum integration range of phase noise for jitter calculation?__

__I think the integration range of 1k~20MHz is enough, because total ADC's conversion time is 100us and 20MHz=10MHz(Fundamental X2)__

__Is it proper approach?__