cadence transient and pss simulation

[balkesli]

Hi, I want to analyze distortion in a single output opamp. First, I fed the circuit with a single tone signal and used transient simulation - measurement/spectrum tool to get frequency response. Then I tried PSS analysis. I got different results i.e. SFDR was different, output magnitude was different, harmonic magnitudes were different. I wonder: Should we trust transient analysis? Is PSS for switching or and oscillating circuits like switched cap, PLL, oscillator? Thank you.