what wrong with my spectre?

[didibabawu]

I am doing the dft analysis to an ideal sinwave using the calculator, I use the conservative to run the tran analysis,but I get a result of only 55db for an ideal sinwave.
So can anyone tell me what's wrong with my simulation, what is needed to be set in the spectre ? Thank you very much.

the sampling frequency i used was 200M, and the frequency of the sinwave was 80.2734375M, I analysis 1024 points.

 

[saro_k_82]

Does not look like a leakage problem.., What is your sine amplitude i.e how much do you expect

 

[didibabawu]

If I set the maxstep=0.1n I can get very good result more than 100dB,but without the setting it's much worse.

 

[wpchan05]

can you change the time step parameters in the transient sim's option? This gives you fixed time samples of your ideal sin wave.

 

[joshuajoanna]

Ideal sinwave has only one tone in the spectrum. Does your 56dB or 100dB represents the tone's amplitude? Or a minus value represents other frequency noise?