Divide by 10 prescaler for frequency counter - Page 1
Forum section: electronics / rf-microwave

author: SingedFingers
author_rank: Frequent Contributor
timestamp: April 01, 2017, 08:59:56 pm
content: Does anyone know of a suitable prescaler IC that can divide by 10 only? I've seen a million that divide by powers of two.Basically I've just grabbed an HP5328A without the C option that will count up to 120MHz. Need to push a little higher than that up to 145MHz for a project so I figured I should probably whack a prescaler on it. I've got a nice Pomona box waiting for it but nothing to put in it. Don't need a preamp or terribly low sensitivity but I'd like it to be able to handle at least +10dBm without turning to ash as a safety measure. If that's not feasible I have a couple of attenuators floating so no big deal.Ultimately I will grab a C option module for the HP5328 when one makes an appearance but for the sake of a single project, a quick prescaler hack will do the job.

author: SingedFingers
author_rank: Frequent Contributor
timestamp: April 01, 2017, 09:02:33 pm
content: Actually please ignore this. I just walked straight in and found onehttp://uk.rs-online.com/web/p/prescaler-circuits/0463931/ffs call the dickhead police please

author: Gyro
author_rank: Super Contributor
timestamp: April 01, 2017, 09:25:04 pm
content: Not sure if you can salvage anything useful from my project, I was in the same situation but had an old Plessey divider in my scrap box...https://www.eevblog.com/forum/projects/my-600mhz-prescaler-(from-the-scrap-box)/msg1074092/#msg1074092Edit: Actually, the RS one looks plenty sensitive on its own. I wish I'd bought one!

author: SingedFingers
author_rank: Frequent Contributor
timestamp: April 01, 2017, 09:56:37 pm
content: Will take a look in detail at that - thanks. Input protection is the big one for me as I can see me toasting that IC in two minutes flat as I have no accurate power measurement apparatus, ironically because I recently blew up my HP8482A power sensor

author: DimitriP
author_rank: Super Contributor
timestamp: April 01, 2017, 10:38:17 pm
content: And if you don't mind a preinvented wheel... here is a 12GHZ prescaler from VE2ZAZ :http://ve2zaz.net/hp5328a/hp5328a_prescaler.htm

author: SingedFingers
author_rank: Frequent Contributor
timestamp: April 01, 2017, 10:49:12 pm
content: Yeah I saw that, then saw the price of the HMC363S8G's. Tacking an external /10 on is good enough for me.

author: retrolefty
author_rank: Super Contributor
timestamp: April 02, 2017, 02:17:03 am
content: An 11C90 was the goto decade divider back in the 80s or so when I was playing with homebrew FC designs. Some ebay NOS sellers still have them available.http://www.ti.com/lit/ds/symlink/11c90.pdf

author: Theboel
author_rank: Frequent Contributor
timestamp: April 02, 2017, 02:45:04 am
content: what about MC12080DR2G still available and cheap enough.https://www.arrow.com/en/products/mc12080dr2g/on-semiconductor

author: LaserSteve
author_rank: Super Contributor
timestamp: April 02, 2017, 03:23:34 am
content: Allow me to help you on the power measurement. A really great guy did this for me long ago, long before i have the four different RF power and RF voltmeters I own now!http://www.techlib.com/electronics/detect.htmS.

author: SingedFingers
author_rank: Frequent Contributor
timestamp: April 02, 2017, 08:31:15 am
content: That's what I'm using at the moment actually. I built this and use it with a 50R terminator:1n270 + 4.7M (or 4.3 - can't remember) resistor (gives rough RMS voltage), a couple of capacitors, a header pin and some RG-174.The shitty resistor hack above has been replaced by a nice Vishay MRS25 one since I took that as I didn't have the right one on hand originally.Unfortunately it sucks compared to a nice HP power meter which I kind of got addicted to.

author: LaserSteve
author_rank: Super Contributor
timestamp: April 02, 2017, 01:30:16 pm
content: Search AD8302 on Ebay...LINEAR Technology makes similar devices.S.