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Power spectrum problem with dBm/Hz and dBm

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jackie1116

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Power spectrum unit ?

I want to input a -60dBm/Hz power in 4MHz ,but our signal generater can only
input dBm signal ,if i press -60dBm on signal generater, I don't know that is right?
and what is different between dBm/Hz and dBm .

Can anyone tell me !

thank a lot
 

vfone

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Re: Power spectrum unit ?

To avoid too many explanations just set your Signal Generator modulation for CW and you get dBm/Hz = dBm.
 

biff44

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Re: Power spectrum unit ?

It is getting harder and harder to figure out what posters are trying to ask. I URGE everyone to write as long and detailed a question as possible. The language barrier is getting fierce

Are you trying to output a single tone? Then the power in dBm/Hz is the same as the power in dBm.

Are you trying to output broadband noise at a -60 dBm/Hz level over a 4 MHz bandwidth? Then you have to modulate your signal generator with a noise source at a modulation input. Your power that would be measured on a CW power meter would be -60 dBm/Hz +10 Log (4 MHz) = -60 +66 = +6 dBm. i.e you would have 1 millionth of a watt in each hertz of bandwidth, times 4 million chunks of 1Hz bandwidth.
 

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