53131a strange behaviour? - Page 1
Forum section: electronics / repair

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: May 15, 2020, 04:18:08 pm
content: Hello,Why sometimes my counter does not update the frequency on the display as i move from 10MHz to 1kHz? The instrument is working and pass all tests, but now i have noticed that unusual behaviour. This especially start to happens when i choose time to 1sec. And even if i make change to default timebase 0.100s i have the same situation. But if i change the frequency from 10 to 15MHz than updates normally, but if i go from 10Mhz to 1kHz does not update it on the display.Thank you in advance!Hrvoje

author: jadew
author_rank: Frequent Contributor
timestamp: May 15, 2020, 04:48:15 pm
content: Hey,I have noticed this behaviour also (along with other cases where it seemingly gets stuck). I believe in this scenario, it's because it's using the initial data to set up the rest of the measurement, and since the odds are that you're switching in the middle of a measurement, it will continue waiting for a lot more edges than you are providing, causing it to look like it's stuck.Cheers

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: May 15, 2020, 04:54:50 pm
content: Quote from: jadew on May 15, 2020, 04:48:15 pmHey Jade!First of all thank you so so so much for your reply!So this is normal, my counter is not faulty? But why sometimes normally update the frequency from 10Mhz to 1kHz, and sometimes not? Is this something buggy in the firmware of the counter?And, i confess, as a typical eletronics tech. i am nitpicky and sometimes "paranoid"to the perfection of the electronic equipment, my curse is that i notice EVERYTHING, i could be a perfect HW tester for the Keysight(d*amn, why they changed the name?)Kind Regards,Hrvoje

author: jadew
author_rank: Frequent Contributor
timestamp: May 15, 2020, 05:02:53 pm
content: Quote from: Hrvoje_CRO on May 15, 2020, 04:54:50 pmYes, I believe this is perfectly normal.The reason sometime it happens and other times it doesn't, it probably has to do with when in the change happens. If it's towards the end, or closer to some sort of checkpoint, you probably won't notice it. Also, it depends on what frequency you switch to, or if you go through other frequencies in between. For example, if you switched to 100 kHz, then it would get stuck only a little.Edit:I just tried it with the settings you mentioned and I have a tough time doing it at 0.1 s gate time, but at 1 s, it's always doing it.Edit 2:I verified this behaviour on a newer unit, and it behaves exactly the same.Keep in mind, that based on your luck, it could be waiting up to 10 000 longer than the set gate time, when you switch from 10 MHz to 1 kHz.

author: TheSteve
author_rank: Unknown
timestamp: May 15, 2020, 08:16:21 pm
content: I can confirm I've seen the same behavior with a 53132A.

author: JohnPi
author_rank: Regular Contributor
timestamp: May 16, 2020, 06:00:22 pm
content: The counter detects unstable frequencies -- if the frequency varies by more than about 20 % (not sure of the number) during the measurement cycle, it will not display/update a count.

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: May 17, 2020, 01:39:01 pm
content: Hi guys!Well now i have another concern.Why this happens;as i choose from HiZ on my siglent to 50 Ohm and do the same on the counter, the counter does not measure the frequency? Setting on siglent is 100mvPP. But if i choose higher frequency, the counter starts to measure it. Also if i higher the VPP from 100mvPP to 1V, everything works normally. I have filmed this so you can check if this is normal or not, or i'm doing something wrong as i am relatively new playerLink for video is herehttps://easyupload.io/2fqj98Thank you in advance!Hrvoje

author: jadew
author_rank: Frequent Contributor
timestamp: May 17, 2020, 01:56:26 pm
content: What happens if you press RUN, when it's misbehaving?For the record, 100 mVpp into 50 Ohm should be detectable. The minimum specification between 100 kHz and 100 MHz is -21 dBm, which is a bit more than 50 mVpp.If it still doesn't measure what you expect it to measure after you hit RUN, then something in the signal path could be faulty, but start by suspecting the cable/connection first, and then the counter.

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: May 17, 2020, 02:34:20 pm
content: Quote from: jadew on May 17, 2020, 01:56:26 pmWhen i press RUN when it's misbehaving it starts to show selected frequency. I also noticed something else. After i power up the counter and connect 1kHz HiZ to counter (on the counter is all default after power up), the counter missbehaves. But as i hit the RUN it shows 1kHz. Also during this missbehaving, if i unplug the cable from Siglent and connect it to the rear output of the counter which is 10MHz, the counter does not missbehave. It show exact 10Mhz, but if i unplug the cable and plug it in Siglent (frequency 10Mhz 100mvPP) the readings on the counter are misbehaving until i press RUN. Strange...