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How to add a flicker noise source to a component ?

wighou

 Hello,

 I didn't find any noise source in the analogLib. Does exist a way to generate flicker or shot noise ? In the positive case, is this noise cyclostationnary (dependent of the instantaneous value of the signal) ?

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  • Andrew Beckett

    Hi Emmanuel,

    VerilogA is supported in spectre, UltraSim and APS - it does not require a digital engine (it also works in AMS and also SpectreVerilog, because the analog solver is in both).

    If you use the flicker_noise() and white_noise() functions, they are treated as small-signal noise sources (normally) and so the noise affects the simulation results in any small-signal noise simulation - so that could be noise, sp, pnoise, psp, qpnoise, qpsp, hbnoise analyses. Note that the "p" and "qp" and "hbnoise" analyses are actually small signal analyses, although they are biassed around a large signal solution (from pss, qpss, hb analyses) which captures the circuit's non-linear response to a large signal. They do not however capture the circuit's non-linear response to the noise (normally that's OK, because usually the circuit does not have significant large signal response to the noise).

    So yes, you can use them in oscillator phase noise analysis.

    It's also possible to use transient noise (enabling the noise sources during a transient). If you do this, your VerilogA noise sources will generate noise during the transient and thus your circuit can have a large signal response to that noise. Note that this is not a terribly efficient way of measuring noise, but it can be useful when you have either non-periodic behaviour or the circuit will distort based on the size of the noise sources (i.e. has a non-linear response to the noise).

    Best Regards,

    Andrew.

Reply
  • Andrew Beckett

    Hi Emmanuel,

    VerilogA is supported in spectre, UltraSim and APS - it does not require a digital engine (it also works in AMS and also SpectreVerilog, because the analog solver is in both).

    If you use the flicker_noise() and white_noise() functions, they are treated as small-signal noise sources (normally) and so the noise affects the simulation results in any small-signal noise simulation - so that could be noise, sp, pnoise, psp, qpnoise, qpsp, hbnoise analyses. Note that the "p" and "qp" and "hbnoise" analyses are actually small signal analyses, although they are biassed around a large signal solution (from pss, qpss, hb analyses) which captures the circuit's non-linear response to a large signal. They do not however capture the circuit's non-linear response to the noise (normally that's OK, because usually the circuit does not have significant large signal response to the noise).

    So yes, you can use them in oscillator phase noise analysis.

    It's also possible to use transient noise (enabling the noise sources during a transient). If you do this, your VerilogA noise sources will generate noise during the transient and thus your circuit can have a large signal response to that noise. Note that this is not a terribly efficient way of measuring noise, but it can be useful when you have either non-periodic behaviour or the circuit will distort based on the size of the noise sources (i.e. has a non-linear response to the noise).

    Best Regards,

    Andrew.

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