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changing the simulator sampling time

nevinalex1234

 Hi

I was trying to import cadence spectre values into matlab for analysis. I assumed that cadence samples a sinusoid for a given freq, for example if theoretically from transient signal of length upto 350ps i was expecting 1ps samples(sampled at 1000GhZ), ie 350 samples. But when i imported the values into MATLAB, there are hardly 80 odd values. The envelope of the wave resembles by cadence plot, but still i have lost a lot of values. Isnt the simulator trying to negate out some redundant values. 

How do i change/freeze the simulator sampling time so that i recover the entire values ?

  • Why do you think it should be sampled? spectre uses variable (adaptive) timesteps to ensure it follows signals to the desired accuracy - so there's nothing that would give you a regularly spaced timestep (by default) - why would it sample at 1000GHz unless you told it to?

    You can specify the strobeperiod parameter on the tran analysis (see "spectre -h tran") to specify that the simulator should write out the results at the specified interval - note that it also ensure that it solves at these strobeperiod timepoints - although it will also solve at intermediate points too if needed to preserve accuracy, but won't output them by default (unless you set strobeoutput=all - which is only available in relatively recent versions of MMSIM).

    Regards,

    Andrew.

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