HiI use the Moto 12080 prescaler chip for that application on my various counters. it's strappable for Div by 10 and works in excess of 1 GHz, easy to feed. Sensitivity in the -20 Dbm range 50 ohms. SMT package. Cheap too. I have some excess boards 3/8 inch by 1 1/2 inch with on-board regulator. if anyone is interested. Bob, KE6F
-----Original Message----- From: Richard (Rick) Karlquist <[email protected]> To: Discussion of precise time and frequency measurement <[email protected]>; Bob kb8tq <[email protected]> Sent: Thu, Jan 24, 2019 9:01 am Subject: Re: [time-nuts] Prescalers ? On 1/24/2019 5:17 AM, Bob kb8tq wrote: > Hi > > If you have a one time need to get to 1.3 GHz then some sort of cobbled > together dead bug chip solution > would be my pick of how to get it done. Cost wise it wold be hard to beat. > There are also cooled up approaches It may seem like prescalers are a simple fool proof technology, but actually they are far from it. I got educated 40 years ago when I designed the HP 5334B counter C channel. The 5334A used an HP made divide by 10 prescaler that cost $100. I replaced it with a $2 COTS divide by 16 prescaler. There was a production test for the 34A that used an HP8660 synthesized sig gen. I wanted to leverage this test for the 34B. The test IIRC involved driving the C channel with 1.3 GHz at the minimum specified sensitivity. But it called out using a mini-circuits 1 GHz high pass filter between the 8660 and the 5334A. What? Turns out that the wideband noise floor of the 8660 corrupted the measurement on the 34A, unless this filter was used. Also turned out that the 5334B with a completely different C channel had the same problem. OTOH, the 5316 did NOT have this problem. It used a different HP made prescaler than the 34A. What was different is that the 5316 prescaler had STATIC flip flops. Unfortunately, I don't know of any COTS static flip flops that are available. If the signal you are trying to measure is very clean, you can get good results just about any prescaler. You will need to arrange for the drive level to be in the "sweet spot" for that prescaler. Otherwise, all bets are off. Getting a prescaler that works over a wide dynamic range is whole 'nother discussion. Rick N6RK _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
