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Re: NOISE FLOOR CORRECTION

The Noise Floor correction has nothing to do with a CSO beat or any other beat. It is a correction factor used to offset the spectrum analyzer noise. The spectrum analyzer has RF amplification (not internal amp function) that must be compensated for. When using a spectrum analyzer to measure carrier to noise, disconnect the input cable and measure the drop in the noise floor. This will be the "system" noise you want to measure. This drop is what is used to determine the proper correction from the standard noise correction chart. It is not recommended to try and measure carrier to noise when the noise floor does not drop 2 dB or less. It is recommended that, in this case, a pre amp be used to raise the carrier and noise of the system high enough to be distinguished from the analyzer noise. Most modern spectrum analyzers (HP-8591C, Agilent 4411B, Tektronix 2715, etc) will have built in programs that take care of this correction.

When measuring CTB or CSO, a direct measurement is all that is needed. Simply measure the carrier, set the analyzer to Marker Delta, then measure the beat. That is all there is to it.

Jim Wallace


> IF NOISE FLOOR DELTA LESS THEN 2 db (SAY BETTWEN CSO BEAT AND NOISE FLOOR MEASURED IN FLAT NOISE AREA OF THE SA)SO THERE IS
> A CERTAIN NOISE CORRECTION FACTOR .
> IF DELTA IS GREATER THAN 2 db THE CORRECTION F IS ANOTHER THING (I HAVE THE FORMULA TO CALCULATE).
> WHAT I NEED AND ASK FOR IS THE CORRECTION F FOR LESS OR EQUAL TO 2 db.
> thanks alot
This is CABL.com posting #72879. Tiny Link: cabl.co/ms7D
Posted in reply to: NOISE FLOOR CORRECTION by alon3
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