Any tips on debugging SpectreHDL schematics

Hi,

I have a simulink model for a delta-sigma modulator
and it is working fine. I am trying to transform this
to a switch level schmatics with all ideal components
(written in SpectreHDL), but I cannot get the loop stable.
I tried breaking the loop somewhere and applying a
step input and comparing the response with Simulink
model, and the response looks very similar. But as soon
as I close the loop the waveforms are totally different.

Does anyone have similar experience and could you please
share your experience and how you solved this problem,
what could be wrong, what is the effective approach to
debug the problem, anything, since I am stuck here for
several days. thank you very much.

 

If you are working in Analog Design Environment, you could use the
debugger. It is available from the Simulation menu. At the bottom you
have "netlist and debug AHDL".

In ahdlLib there is a component called "sigmadelta_1storder" you could
look at to check how cadence implements their modulator.