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dBm option in Cadence Waveform window provides funny results !! (Read 51 times)
AnalogAroma
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dBm option in Cadence Waveform window provides funny results !!
Jul 26th, 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 !!!!!!!!!!!
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