[time-nuts] Spectracom 8140 distribution amplifier and the Taps- some application info
lists at rtty.us
Thu Jul 28 00:08:39 UTC 2011
Based on your data the floor of the taps are a bit lower than I thought. I have only looked at a full system end to end. I was looking at AVAR so the numbers would not compare directly.
Very few people have lab standards that run -120 dbc/Hz at a 1 Hz offset. Even fewer instruments have a floor below that. Looks fine for driving test gear. Not what you might choose for a phase noise standard.
On Jul 27, 2011, at 7:10 PM, John Ackermann N8UR <jra at febo.com> wrote:
> I'm not sure if there's been other data posted, but a few years ago I did phase noise measurements of the 8140T as well as HP 5087A and TADD-1. That info is at
> I got my hands on a tub full of 8140Ts but don't have the 8140 driver. However, all you really need to drive the taps is 10 MHz at ~10 dBm (not sure the exact spec) riding on 12VDC.
> I built a power injector to put 12V on a 10 MHz sine wave tapped off the 10811A output in a 5065A Rb and used that to drive a string of about 10 8140Ts in my old lab. I terminated the string with a blocking capacitor and 50 ohm load; you need the capacitor to keep the DC off the load.
> As has been pointed out, the 8140T isn't the lowest noise distribution system you can get, but it sure is a convenient way to put a bunch of 10 MHz spigots around the basement and the performance is adequate for anything but the most critical applications.
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