Stats

  • Locked Locked
  • Replies 5
  • Subscribers 125
  • Views 23978
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

PSS, PNOISE and Transient Noise

pcardoso73

Hi all,

 I have several questions which i will describe by topics. All the circuit design is made in Candence using Spectre.

 1 - As transient noise introduces noise in the transient simulation, I export the data to Matlab to perform the Jitter (RMS and Peak-to-Peak) calculations. How can I do this in Cadence ?

2 - How can be compared the results obtained from MatLab (from Cadence exported data), and those obtained by cadence ?

3 - What kind of noise is introduced by transient noise ? Can this noise be upconverted into phase noise ?

4 - Calculating phase-noise using PSS+PNOISE, if done with transient noise on, will affect the phase noise analysis result ? Should I disable the transient noise, when performing PSS and PNOISE ?

 5 - I am designing a VCXO for a PLL. The requirements are: frequency - 80 MHz, tunning range - +- 8 kHz, cload 15 pF. To simulate this circuit with transient noise I have used the following parameters:

Noise Fmax 1e9
Noise Fmin 10k
Noise Seed 1
Noise scale 1
Noise Tmin 4u

Is this correct ?

 

Thanks To all.

 

Best regards,

Pedro 

Parents

  • Pedro,

    The results of the pnoise will not be affected by whether you are running transien tnoise or not.

    Note that integrating the result to obtain the jitter is not necessarily correct - because you need to be aware of the fact that there is a log relationship, plus the fact that if you're doing multi-cycle jitter you can only integrate over the band which you've simulated in the pnoise analysis. I suggest you take a look at the Jitter app note that is in <MMSIMinstDir>/tools/spectre/examples/SpectreRF_workshop . I don't know how you've calculated it or what you're comparing with.

    Regards,

    Andrew.

Reply

  • Pedro,

    The results of the pnoise will not be affected by whether you are running transien tnoise or not.

    Note that integrating the result to obtain the jitter is not necessarily correct - because you need to be aware of the fact that there is a log relationship, plus the fact that if you're doing multi-cycle jitter you can only integrate over the band which you've simulated in the pnoise analysis. I suggest you take a look at the Jitter app note that is in <MMSIMinstDir>/tools/spectre/examples/SpectreRF_workshop . I don't know how you've calculated it or what you're comparing with.

    Regards,

    Andrew.

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.