The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Simulators >> Circuit Simulators >> Transient noise simulations
https://designers-guide.org/forum/YaBB.pl?num=1256737141

Message started by currant on Oct 28^th, 2009, 6:39am

Title: Transient noise simulations
Post by currant on Oct 28^th, 2009, 6:39am

Hello,

We use spectre transient noise analysis and we get from it very strange results.
Device - BandPass SigmaDelta ADC. It is very unexpectedly for us, that if we increase noisefmax, we get a better SNR.
Did anybody have a same problem or have an explanation of that behavioral?

Many Thanks.

Title: Re: Transient noise simulations
Post by Riad KACED on Nov 9^th, 2009, 12:51pm

Hi Currant,

You better report your problem to your simulator vendor, i.e. cadence if Spectre. The noisefmax is directly linked to the simulation time step (The maximum time step of the transient analysis is limited to 1/noisefmax). Though I don't see why increasing noisefmax would decrease the noise power, i.e. increase the SNR.

Berkeley Design Automation have issued a WP where they give some recommendation for noisefmax/tstep/tstop versus ADC's input frequency and clock frequency. You can check out the paper at http://www.berkeley-da.com/prod/datasheets/Berkeley_DA_Noise_Analisys_Analog_RF_WP.pdf

Cheers,
Riad.