Time mark generator.I need opinions: - Page 1
Forum section: electronics / testgear

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 04, 2016, 02:49:43 am
content: http://produto.mercadolivre.com.br/MLB-741929117-labindependente-gerador-de-marcas-001-a-500mhz-_JMPlease, opinions are welcome.Anybody knows the model on the link?

author: justinDavidow
author_rank: Newbie
timestamp: March 04, 2016, 03:09:01 am
content: That appears to be a Tektronix 2901Someone did a teardown here a few years back:https://www.eevblog.com/forum/reviews/tektronix-2901-time-mark-generator-tear-down-inspection/

author: sorenkir
author_rank: Regular Contributor
timestamp: March 04, 2016, 10:18:08 am
content: I have one, it suffered from intermittent contact due to one bad solder joint, easily fixed once identified and you manage to remove the boards...It has some sort of "ovenized" quartz oscillator, but with mechanical thermal control!The 20/100/200/500 MHz output amplitude is not calibrated.Not of very much use, except if you plan to check/calibrate timebases of vintage analog scopes...Michel.

author: tautech
author_rank: Super Contributor
timestamp: March 04, 2016, 10:23:16 am
content: Quote from: sorenkir on March 04, 2016, 10:18:08 amThat's exactly their intended use and invaluable for such.

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 04, 2016, 12:39:23 pm
content: Thank you all for answers. This other device is capable of do the same than time marker?http://produto.mercadolivre.com.br/MLB-745859341-gerador-de-pulso-hp8082a-arduino-agilent-_JMSomebody on the forum said me that a pulse generator is excelent to time base calibration too.You agree?

author: markce
author_rank: Regular Contributor
timestamp: March 04, 2016, 01:12:23 pm
content: QuoteDepends on its specs. You will need like 1% (or 5%) calibrated pulse repetition accuracy and stability and(depending on the scope to calibrate) high rates. With a frequency counter, lack of accuracy in the generator can be compensated for.A fast digital generator could do nice.

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 04, 2016, 01:31:38 pm
content: Quote from: markce on March 04, 2016, 01:12:23 pmmarkce do you know the model of the link? It's a HP8082A.http://www.libertytest.com/assetmanager/uploaded/pdf-20081211-164348-hp_8082a.pdf

author: tggzzz
author_rank: Super Contributor
timestamp: March 04, 2016, 01:53:20 pm
content: Quote from: SAUL BRITTO on March 04, 2016, 02:49:43 amSo, you think that is yoursolution. It may or may not be.If you tell people yourproblem, you may get better answers or better solutions.

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 04, 2016, 02:28:43 pm
content: Quote from: tggzzz on March 04, 2016, 01:53:20 pmSomebody said me that a pulse generator like this on the link is capable of the same work as a time generator.Is this I want to know.I believe the people understood my question.Look: Thank you all for answers. This other device is capable of do the same than time marker?http://produto.mercadolivre.com.br/MLB-745859341-gerador-de-pulso-hp8082a-arduino-agilent-_JMSomebody on the forum said me that a pulse generator is excelent to time base calibration too.You agree?Quotepulse generator is excelente to calibrates scopes tooDepends on its specs. You will need like 1% (or 5%) calibrated pulse repetition accuracy and stability and(depending on the scope to calibrate) high rates. With a frequency counter, lack of accuracy in the generator can be compensated for.A fast digital generator could do nice.« Last Edit: Today at 12:18:49 AM by markce »

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 04, 2016, 02:36:15 pm
content: TGGZZZ> I think the people understood my question...

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 04, 2016, 02:44:56 pm
content: tggz if you are not satisfied with my presence at this forum and happens to be an administrator feel free to block my profile I'm sorry but I hate persecution and stupid reproaches.

author: tggzzz
author_rank: Super Contributor
timestamp: March 04, 2016, 02:58:26 pm
content: Quote from: SAUL BRITTO on March 04, 2016, 02:36:15 pmThe trick is to learn to ask therightquestion. That's a good lesson to learn in life, not just on this forum. You will find that it is easy to answer questions, but much more difficult to determine which is the important questiom - i.e. the one which causes you to do A rather than B.If you look at your first post, you gave a link and asked for opinions.An answer that is acompletelysufficient answerto that questionis "It will not be a good way of checking your radio receiver's calibration".Now, if you wanted to use it for some other purpose, it would help if you stated the purpose. It is also polite, since it avoids people wasting their time giving answers that don't help you.Anyway, either you will learn, or you won't.

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 04, 2016, 03:01:47 pm
content: Quote from: tggzzz on March 04, 2016, 02:58:26 pmAs I said: if you don't agree with my presence on the forum...

author: Eheran
author_rank: Regular Contributor
timestamp: March 04, 2016, 03:35:06 pm
content: What are you even talking about?He wants to help you. But for anyone to be able to help you further... u have to give us information about what you actually do/need. No need to make tripple-posts every 8min. Futher there is "ever" any need for a quote of a whole post. Only quote if u want to respond to a specific part of a post and then only quote that part...And since you only have one sentence and its the last post in this thread: I dont need to quote you now at all.

author: tggzzz
author_rank: Super Contributor
timestamp: March 04, 2016, 03:59:26 pm
content: Quote from: Eheran on March 04, 2016, 03:35:06 pmWell, yes.See what lead up to my responsehttps://www.eevblog.com/forum/repair/can-anybody-explain-me-really-how-works-that-time-base-of-hp-scopes-1740a-and/msg884541/#msg884541

author: markce
author_rank: Regular Contributor
timestamp: March 04, 2016, 05:58:31 pm
content: HP8082A certainly is a fast pulse gen. As far as I can see, it is not super precise, so you'll need a frequency counter as well.The HP8082A uses special HP IC's, so be carefull not to break it.Do you really need this fast? To check/adjust a 20MHz or 50MHz scope it's overkill.

author: chris_leyson
author_rank: Super Contributor
timestamp: March 04, 2016, 06:29:07 pm
content: Hi Saul, the TEK 2901 is an old piece of equipment you would need to replace the electrolytic caps if they havn't already been replaced and check the sockets for any signs of corrosion. Check the crystal oscillator with a frequency counter if you have one.Chris

author: ebastler
author_rank: Super Contributor
timestamp: March 04, 2016, 06:52:38 pm
content: Quote from: markce on March 04, 2016, 05:58:31 pmI agree. If this purchase is triggered just by the HP scope alignment task described in the other thread which tggzzz linked to, then buying a dedicated timing or pulse generator might be overkill per se.I understand that you already have a function generator, but do not quite trust its output frequencies? Why not buy a decent frequency counter instead? That would help you to establish a known reference signal for timing adjustments, and will be much more useful for your future electronics projects.Saul -- giving advice along those lines would indeed be easier if you could state what problem you are trying to solve. I.e. what you want to do with the generator? (Including e.g. some details about the type(s) of scope you want to adjust, if that is the main purpose.)

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 15, 2016, 06:16:07 pm
content: I bought this unit of tek 2901 and it's in my bench I see that orange light signal named oven,it some times goes on and of.I need to know if it just lit when is trying to do an adjustment of frequency. Is this a normal behavior?

author: 1xrtt
author_rank: Regular Contributor
timestamp: March 15, 2016, 06:46:48 pm
content: Yes, the internal crystal is kept inside an oven, for thermal stability, so the oven turns on and off frequently.Here is a picture:from this thread:https://www.eevblog.com/forum/reviews/tektronix-2901-time-mark-generator-tear-down-inspection/msg73606/#msg73606

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 15, 2016, 07:11:31 pm
content: Quote from: 1xrtt on March 15, 2016, 06:46:48 pmThank you. I bought this device recently in truth, the mail delivered me today and, I was in doubt.

author: PaulAm
author_rank: Frequent Contributor
timestamp: March 16, 2016, 01:03:21 pm
content: Did you get the manual for that generator?You can find the service/operating manual here:http://w140.com/tekwiki/wiki/2901The sixth paragraph under operating instructions says to allow 2 hours for the oven temperature to stabilize and then 5 minutes after turning it on. The note immediately following that explains when that light comes on.The first thing I do when I get a piece of equipment is track down a manual and read it. That's generally more efficient than asking random questions.

author: tggzzz
author_rank: Super Contributor
timestamp: March 16, 2016, 01:24:51 pm
content: Quote from: PaulAm on March 16, 2016, 01:03:21 pmPersonally I look at the manualbeforeI buy something. If I can't find a manual, I usually don't buy it.QuoteArguably that's not a more efficient use ofhistimeHe would probably get ausefulanswerfasterthat way, though.