开云体育

----- Original Message -----
From: "Chris Johnson" <strangequark65@...>
To: <TekScopes@...>
Sent: Thursday, February 01, 2007 4:55 PM
Subject: [TekScopes] Birdies on a 492....what's normal?

I've got a 492 that I haven't had for very long and I'm still
exploring the possibilities with it. It has options 1,2, and 3.


It's a very clean performer and seems to meet its sensitivity specs
and is reasonably close to calibrated.


I do notice a few birdies in it, and while I don't expect any spetrum
analyzer to be entirely free of birdies, I'd just like to know if the
ones I'm seeing in this unit are about normal.


Of course it has some noise below 100 MHz. I see a spur at about 34
MHz that's about 20 dB above the noise floor with the video filter set
to narrow.

At 41 MHz, there's another spur that's about 15 dB above the noise floor.

At 50 MHz, +25 dB.

At 69 MHz, +8 dB.

At 75 MHz, +12.

At 85 MHz, +19

At 93 MHz, +20.

At 99 MHz, +18.

At 100 MHz, +19.

There's a big one at 300 MHz, +25.

At 350 MHz, +20.

At 400 MHz, +10.

At 500 MHz, +10.

Below 100 MHz, there are smaller spurs between the larger ones,
typically less than 10 dB above the noise floor.

Above 500 MHz, it's very clean.

The apparent magnitude of the spurs does vary somewhat according to
the span and resolution in use.

All figures reported are in minimum noise mode with the ref level and
attenuation adjusted to as to yield the largest apparent magnitude
of the spurs.


So is this about right for a 492 or is it more in need of calibration
(or even repair) than I thought?


CJ





Yahoo! Groups Links