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Simulators >> RF Simulators >> dBm option in Cadence Waveform window provides funny results !!
https://designers-guide.org/forum/YaBB.pl?num=1248617376

Message started by AnalogAroma on Jul 26^th, 2009, 7:09am

Title: dBm option in Cadence Waveform window provides funny results !!
Post by AnalogAroma on Jul 26^th, 2009, 7:09am

Hi Everybody,

I have calculated the psd of a periodic signal with psdbb function from the Calculator -function menu. The psdbb function provides rms-squared output. When I change the scale of the curve to dBm , I get very strange results.
One example is that psdbb gives a value of 323.4 u at 101.6KHz. Using the dBm formula , the dBm value should be -21.89 dBm. But, if you use cadence dBm scale, you will get -4.902 dBm. The diffrence is equal to 10 log 50 !!

It looks like Cadence use 1 ohm to calculate dBm !!!!!!!!!!!