Measuring SpreadSpectrum Tx Power

For total power in that range, you can perhaps find a thermal converter--one that dissipates the input power in a load resistance, and monitors the temperature rise. It's typical to do it in a bridge circuit, where an identical converter is driven by DC to match temperature rises. The DC input power then matches the RF input power, and is easy to measure. You can also use an attenuator to reduce the power to a level where one of the broadband RF detectors from Analog Devices or Linear Technology or similar can be used directly--they generally operate in the -60dBm to 0dBm range, more or less.

For power spectral density, you'll want to be using a spectrum analyzer. There are advantages to using a spectrum analyzer that digitizes a relatively wide swath of spectrum all at once, but you can also use a swept analyzer. Modern spectrum analyzers should have power spectral density displays that you can read directly; or you can convert from the indicated power to density if you know the resolution bandwidth of the analyzer.

I don't know for sure what you'll find, but try looking on the Agilent Technologies website for "white papers" and ap notes on spectral measurements. Seems like there should be some good general articles there, and maybe something very specific to what you want to do. Web sites of some other spectrum analyzer suppliers may also turn up useful resources: Rohde & Schwarz and Anritsu come immediately to mind, but there are others too.

Cheers, Tom

Several people - Boonton, Agilent, Keithley maybe - make fast-response wideband RF power meters, suitable for RF burst measurement. Big bucks, mostly.

And these are cute:

A simple diode detector, from Mini-Circuits or whatever, might get you into the rough ballpark, but calibration and matching become issues.

PSD for pulsed RF is a more serious issue.

John

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Also Tektronix comes to mind, which I believe was recently sold to someone? You might also contact Morris Engelson, (formerly with Tektronix), who now has a private consulting practice.

Web:

I was privledged enough to sit through one of his 3-day Spectrum Analysis seminars several years ago, and if he's still doing those, would highly recommend attending. -mpm