Hi,

I've simulated an amplifier circuit in the time domain and have performed an fft on the load signal using the "fs(Vload)" function. For an input of -20dBm I get -14.5dBm at the load.

If I simulate the same circuit using Harmonic Balance with an input of -20dBm I get -8.6dBm at the load.

Does anyone know why I get such different answers?

Thanks.

I've simulated an amplifier circuit in the time domain and have performed an fft on the load signal using the "fs(Vload)" function. For an input of -20dBm I get -14.5dBm at the load.

If I simulate the same circuit using Harmonic Balance with an input of -20dBm I get -8.6dBm at the load.

Does anyone know why I get such different answers?

Thanks.

My suggestion would be to look at the fs() documentation here and see if you should add any extra parameters.

Another thing to make sure is that you are comparing voltage levels in both cases and not voltage level in one and power level in the other case.

You can also read the following documents and see if they can help you:

http://edasupportweb.soco.agilent.com/cgi-bin/show.pl?id=170202

http://edasupportweb.soco.agilent.com/cgi-bin/show.pl?id=59022

http://edasupportweb.soco.agilent.com/cgi-bin/show.pl?id=59842

Thanks

Nilesh 8)