Hello,

I've implemented a VCO-based ADC in Virtuoso. It consists of a 7-stage ring oscillator. The ring oscillator output phases are sampled with 7bit register and finally the sampled output phases are differentiated by 7-stage differentiator. I attached the schematic of my design. It has a pseudo-differential structure. Each path has a VCO, 1st DFF as a phase sampler and  2nd DFF followed by the Xor is the differentiator.

Having had above brief, I want to extract the signal transfer function (Gain and phase Vs. frequency) of the above structure. To be clear, I want to see the low-pass behavior of the VCO (like a continuous-time integrator 1/s), frequency behavior of the differentiator and also frequency behavior of the overall structure (superposition).

Would you please let me know what kind of simulation I have to do to extract this info from my design in Virtuoso? I am using IC616.

Many thanks