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Did you check out the new Pnoise and Hbnoise Choosing Analyses forms in the MMSIM 15.1 and IC6.1.7 /ICADV12.2 releases? These forms have been significantly improved and simplified. The Direct Plot Form has also been enhanced and is much easy to use. Let's look at the changes that have been made in the Pnoise and Hbnoise Choosing Analyses forms.
Below are the Pnoise and Hbnoise Choosing Analyses forms for an oscillator circuit. For both Pnoise and Hbnoise, the sources and modulated options from the Noise Type drop-down list have been replaced with timeaverage, which is a single-sided spectrum and harmonic-referred (modulated) noise analysis. The timeaverage option provides you the following five choices: USB, AM, PM, AM&PM, and ALL(AM,PM,USB,LSB).
The following table shows the noise options that were available in the earlier Pnoise/Hbnoise Choosing Analyses form and the new noise options from the IC6.1.7 and ICADV12.2 releases.
When Contribution Type is AM, PM, AM&PM, or ALL(AM,PM,USB,LSB), Sweeptype is automatically set to relative.
If you are simulating circuits like switched-capacitor filters or sampling circuits, you may select full-spectrum pnoise. In full-spectrum pnoise, you need not set the Maximum Sideband field except in cases where the PSS beat frequency is 100KHz or less. In such cases, set maximum sidebands to the 1/F noise corner frequency divided by the PSS beat frequency. With the full-spectrum setting, Pnoise calculates all the noise translations it can, based on the maximum timestep in the PSS analysis.
Below are the Pnoise and Hbnoise Direct Plot Forms for an oscillator circuit with PM noise type selection.
If you choose USB as the contribution type in the Pnoise/Hbnoise Choosing Analyses form, you cannot plot phase noise from the Direct Plot Form. To plot phase noise, you need to select the PM or ALL(AM,PM,USB,LSB) option. In addition, if you run a Pnoise/Hbnoise simulation with ALL(AM,PM,USB,LSB) contribution type, and choose LSB from the Noise Type section and dBc/Hz option from the Modifier section in the Direct Plot Form, the output that you get is like the old “Pnoise/Hbnoise sources phase noise” plot.
Both AM and PM components in the Direct Plot Form now have a SSB (single sideband) and a DSB (double sideband) selection. You no longer have to remember whether your plot is SSB or DSB.
For more information on performing noise simulation using Pnoise and Hbnoise analyses, you can view the following videos on Cadence Online Support:
Click the video links now or visit Cadence Online Support and search for the video under Video Library.
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Kamal Kishore Tewari