Chinese 10GHZ Prescalar option for Agilent 53131A 53132A Frequency Counters - Page 1
Forum section: electronics / testgear

author: stuartk
author_rank: Regular Contributor
timestamp: January 19, 2019, 05:12:40 pm
content: Has anyone tested these inexpensive 10Ghz eBay prescalars to add a 3rd channel high frequency option to the Agilent 53132A frequency counter? I couple of years ago I purchased a 3Ghz one for my old fluke counter which seemed to work fine.The auction description which is suitably vague, seems to imply that if you already have the high frequency counter option installed by the manufacturer, then their device won't work. I guessing due to a manufacturer eeprom change.The genuine Agilent 12.4Ghz part sells for a whopping $1275, used. It's probably made of solid gold whereas the eBay one looks to be made of chinesium....https://www.ebay.com/itm/HP-AGILENT-53131-53132-53181-8G-Simple-Option-Frequency-Counter-Input-100M-10GHz/262740237472?hash=item3d2c89dca0:g:MKcAAOSwA3dYXNM0:rk:12:pf:0

author: artag
author_rank: Super Contributor
timestamp: January 20, 2019, 12:16:48 pm
content: The usual problem with these copies is that they self-oscillate when there's no input signal, giving misleading results. They can still be useful, though, as long as you're aware of that.I have no experience of that one but it looks as though it has nothing but a bare prescaler so probably suffers from this too.I built a prescaler for a Philips counter which suffered from this problem. Later, I got hold of another example which had the official board in it. I believe this avoids it by measuring the input signal and inhibiting the count if it's too small. Of course, this reduces the sensitivity slightly.

author: sorenkir
author_rank: Regular Contributor
timestamp: January 22, 2019, 02:52:50 pm
content: BNC input connector @ 10GHz ?

author: stuartk
author_rank: Regular Contributor
timestamp: January 22, 2019, 07:35:37 pm
content: I didn't notice that. Here is a pic of the 3GHZ prescalar I purchased for my PM6680:And here is one for the 12.4GHZ Agilent Prescalar for the 53131A 53132ASomething like this might help:https://www.ebay.ca/itm/6inch-N-Type-Female-Jack-to-SMA-Male-Plug-Straight-Premium-RF-Coax-Cable-Adapter/322698357155?hash=item4b225229a3:g:47cAAOSwGIRXcImU:rk:22:pf:0

author: Scratch.HTF
author_rank: Regular Contributor
timestamp: January 26, 2019, 01:04:19 pm
content: Quote from: artag on January 20, 2019, 12:16:48 pmFor blanking the prescaler output (via an AND gate) when no signal is applied (prescaler is self oscillating), the duty cycle of the prescaler output (typically 50%; some prescalers such as the ADF4106 have an output with varying duty cycle depending on frequency - at a 500K division ratio and 64 prescaler ratio for this device, output has ~6.4uS wide pulses with 10 MHz input and ~120nS wide pulses with 500 MHz input) can be monitored with a simple RC filter (for comparison against certain limits with an ADC or window comparator - 10K/100nF has a constant of 1mS) and the prescaler output blanked for a certain time if duty cycle is out of tolerance(which I have yet to try for a prescaler with a 50% duty cycle output when a stable signal is applied).Fitting a blanking override switch will help deal with output blanking when not desired e.g. an unstable frequency input.