How To Lower Noise Floor On Spectrum Analyzer

An example of that process is shown in the figure below.

How to lower noise floor on spectrum analyzer.

Some general tips and tricks 001 in measuring signal using spectrum signal analyzer. If instrument software version is a 18 00 press mode setup noise reduction noise floor extension on. With a spectrum analyzer what is a good method for determining the local noise floor in the lab area around the spectrum analyzer. A spectrum analyzer s ability to measure low level signals is limited by the noise generated inside the spectrum analyzer.

With spectrum analyzers you can do that by either manually setting the attenuation or adjust the ref level to make it change the attenuator. This sensitivity to low level signals is affected by the analyzer settings. Most modern spectrum analyzers offer methods for measuring the noise floor of the spectrum analyzer and then correcting for this in the measurement results methods which have been available for some time. Bandwidth as that of the spectrum analyzer is 10 db or more lower than the danl on the analyzer then the noise figure of the system is that of the spectrum analyzer less the gain of the preamplifier.

Figure 9 for example depicts 50 mhz signal that appears to be shrouded by the analyzer s noise floor. If the snr measured changes at all then you have a bad setup and need to stick more amplification in somewhere to compensate for test losses. You can test by inspection. I have another rf noob question how can spectrum analyser measure noise floor of dut.

The noise will have higher peak to peak variation than when noise floor extension is off but the average of the noise. If the displayed noise does not change then you have fulfilled the. I know that long fft window lenghts or slow sweeps can pull out signal that is even bellow the noise floor becose coherent signals add 6db while incoherent noise adds only 3db thats means long fft or sweep will average the noise down more than the signal. This example is based on keysight s xsa n9030b model.

Note that the level of the displayed noise should be at least 10 db lower than the level noted in the previous step. The narrower the filter the finer the detail that is seen and the lower the noise floor level. Two spectrum measurements of a low power seven tone signal. The same concept.

When measuring the phase noise of a signal using a spectrum analyzer ensure that the noise performance of the local oscillator within the spectrum analyzer is around 6 db better than that of the expected performance of the signal under test. If for example we wanted to determine the noise floor from 0 to 1 ghz would it be best to run a sweep using a full 1 ghz span or would it be better to pick various frequency ranges with smaller spans. To correct the typical power spectrum measurement the average noise floor power in the analyzer s rbw filter is subtracted from each point of a power spectrum measurement.