Spice: Can it display Watts or dBm?

Hi All,

I would like Spice to display results in Watts or dBm. Is this even possible? Spice only seems to want to graph voltages or currents -- and in the FFT portion it only seems to show dB. (I'm using LT Spice).

Thanks for any help!

-Bill

Reply to
billcalley
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I believe it's the Alt key for I*V power.

D from BC

Reply to
D from BC

Hi D from BC,

I should have been far more specific! I meant force Spice to graph the RF output signal in Watts or dBm; and more specifically during a frequency domain FFT output.

Thanks,

-Bill

Reply to
billcalley

Sure it's possible. Try this:

  1. Run your simulation, and display the voltage across a resistor and the current through that resistor.
  2. Right click in the graphics window; select FFT; select both the current and the voltage to display as FFT (so that the FFT will be calculated for both).
  3. In the FFT window, right click the voltage trace label at the top. Change the expression to the voltage times the current.
  4. Right-click in the left margin of the FFT graphic; change to a linear display.

Presto, you should see watts displayed.

Cheers, Tom

Reply to
Tom Bruhns

Thanks Tom -- works like a charm!!

Best Regards,

-Bill

Reply to
billcalley

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