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I'm looking at a Wavetek model 8911 10 MHz-20 GHz Programmable Sweep Generator, It says it gets up to 20 gigahertz, but is it possible that it only generates pulsed DC at that frequency as an excuse to say it gets "20 GHz" It's quite expensive and do not want to waste my money... Also, How can I know if a device produces an AC or pulsed DC current.

Transistor
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Max
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    "DC at that frequency" is an oxymoron. There is no such thing. Also, there is extensive documentation that should come with every device of that class, so read that. – Marcus Müller Feb 04 '18 at 17:08
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    (By the way, short impulses at a rate of 20 GHz are harder to produce than to mix up any wave form to that frequency. Hint: plot the spectrum of a 20 GHz square wave and tell me how much bandwidth you need.) – Marcus Müller Feb 04 '18 at 17:10

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A fine old instrument, I've used one back in the day.

If it's working, then yes, it goes to 20GHz.

Do be aware that it's a sweep generator, not a synthesiser. That means its output frequency has a tolerance, it's not an accurate multiple of a reference frequency. Its main purpose is to provide a swept frequency out of the front, and a linear ramp out of the back, that you feed into the X input of your XY 'scope. Then with a diode detector feeding the Y scope input, you can draw graphs on the 'scope of response versus frequency, for amplifiers, wideband filters etc. What we used to do before RF network analysers were available. It doesn't work so well for very narrow band filters, due to the limited frequency accuracy.

It doesn't produce 10M to 20GHz in one range. It has several oscillators in there covering smaller ranges. On a wide sweep that covers several ranges, it pauses the ramp while the sources switch over, to give joined-up coverage on the 'scope.

Neil_UK
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