how to set spectrum analyzer in time domain

Hi people,

Is it possible to measure/view a signal in time domain using a spectrum analyzer?
If yes, how?
I asked a seller from agilent and the guy told me that what I need to do is to set the spanning frequency to zero?! Is that so?

Thanks in advance,

clk

No.

If you set a spectrum analyzer to "zero span", the display will read the average power level of an RF energy right around where the spectrum anlyzer is tuned. The power meter will act like there is a bandpass filter in front of it, with that filters bandwidth being equal to the "resolution bandwidth".

An oscilloscope, for instance, measures instantaneous voltage (not average power) and shows that trace against time, not power averaged over 1 mS or so.

You can do time-domain RF power measurement for a TDMA signal using the Spectrum Analyzer (in zero span), with condition to use a RBW wide enough to do not affect the measurement. For example in GSM-GMSK a 1MHz RBW is ok, and the term output power refers to the measure of the power when averaged over the useful part of the burst.
Also shall be careful selecting the detector type on your spectrum analyzer.

Spectrum analyzer, if you want to use it in the time domain must have possibillity to switch to linear instead logarithmic display.

if you set the SA in zero span, it acts as a "tuned" oscilloscope. It's show only the amplitude variation (on time domain) of the signal at wich the SA is tuned.
The user should set an appropriate sweep time

Vfone,

How should we select detector type of spectrum analyzer in time domain ?
Also if we do averaging when gating trigger modulation information of GSM burst and sweep over desired frequency span or range, what detector type should we set at this time?

Thanks!

If it is spectrum analyzer, using a zero span is like a narrow bandpass. So far havenot tried this.

Zero Span do not change the bandwidth of the measurement. The test uses the same bandwidth settings as in frequency domain measurements.

For SA detector settings check this document:
http://rfdesign.com/images/archive/302Gorin32(1).pdf