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PSS simulation with oscillator circuit

Rayanna

There is an oscillator part in my circuit. The pulse signal generated by the first ring oscillation part has a width of about 31us.

Using this oscillator, some oscillation signals are subsequently generated with a period of about 62us,

which is used back into the amplifier part. I want to know how to set it during pss simulation, and whether the input port needs to set a frequency. Should I choose shooting or hb, which one should I choose as the oscillation pin, and how to determine the beat frequency. I have set it up many times but it still shows variance errors. I am a newbie looking for help. Thank you very much.

Parents

  • I'd use shooting rather than harmonic balance (since the signals are very square and will need a very high number of harmonics to represent, so using a time-domain approach would be better; with shooting the number of harmonics is much less critical). The frequency is an estimation of the oscillation frequency (the first plot above is not very clear because the top is truncated, but they look like very narrow periodic spikes?). It appears that the spikes are twice the frequency of the output - but that might just be a guess. Anyway, you want to specify the frequency as (roughly) the lowest frequency in the circuit - or you could specify it as the largest period. Give a reasonable additional time for the oscillator to start (it seems to be starting OK in transient) - you have 150u which is a bit short given the periods you are dealing with.

    You don't need to specify a pin node. Specifying the oscillator output is reasonable in ought for the oscillator though.

    Not sure what you mean by "still shows variance errors".

    Andrew

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  • I'd use shooting rather than harmonic balance (since the signals are very square and will need a very high number of harmonics to represent, so using a time-domain approach would be better; with shooting the number of harmonics is much less critical). The frequency is an estimation of the oscillation frequency (the first plot above is not very clear because the top is truncated, but they look like very narrow periodic spikes?). It appears that the spikes are twice the frequency of the output - but that might just be a guess. Anyway, you want to specify the frequency as (roughly) the lowest frequency in the circuit - or you could specify it as the largest period. Give a reasonable additional time for the oscillator to start (it seems to be starting OK in transient) - you have 150u which is a bit short given the periods you are dealing with.

    You don't need to specify a pin node. Specifying the oscillator output is reasonable in ought for the oscillator though.

    Not sure what you mean by "still shows variance errors".

    Andrew

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