[time-nuts] IC for 1 PPS Output

Mike Feher mfeher at eozinc.com
Fri Apr 7 12:02:44 EDT 2006

As I mentioned about 6 months ago, I think the Extron ADA 6 300MX is a very
handy and ready to go distribution amplifier. It has a switch so it can be
DC or AC coupled. It has a built in PS. As it was intended for video
applications it is currently set up for 75 ohms, which as mentioned
previously should not cause any problems, and it has not for me. It has 4
sections with each section providing 6 outputs. So, there are a total of 28
BNCs on the rear panel. The 75 ohms is determined by fixed 75 ohm resistors,
so, if one really wants 50 ohms, they just need to change the resistors. I
am using one stock to distribute a rubidium to about 15 instruments on my
test bench without a problem. I have bought a few for as low as $9.99 plus
shipping on ebay. Personally, I highly recommend it. They seem to be very
prevalent on ebay. The following URL is the specification:


Regards - Mike  

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Brooke Clarke
Sent: Friday, April 07, 2006 12:14 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] IC for 1 PPS Output


I've got the TVB 1 PPS PIC circuit working and would like to add an 
output IC to drive 50 a couple of Ohm cables.
Need two outputs, the normal 1 PPS and also the 10 kHz output since I 
think it would work with the SRS app note for making 1,000 TI 
measurements in one second to better see small offsets.

I seem to remember that there may be an internal resistance already in 
some chips so putting a 47 or 50 Ohm resistor in series may result in an 
impedance above 50 Ohms.  Any thoughts?


Brooke Clarke

w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml

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