Signal generator help - HomeBrew Forum at eHam.net

$\'\'$

$\'\'$

$\'\'$

eHam.net Forum : HomeBrew : Signal generator help

Forum Help

1-10 of 14 messages

Page 1 of 2 Next

Signal generator help	Reply
by WU0L on May 5, 2009	Mail this to a friend!
I recently acquired an HP 675A sweep signal generator cheap but I don't have a manual. Seems like no matter what I do, or settings I use, it puts out two different RF signals of slightly different frequencies. I can observe these on the oscilloscope but my frequency counter cannot resolve between the two and gets all confused. I have never used a "sweep" generator before, but I think I have the sweep turned off and set to "CW". Any suggestions? thanks Mark WU0L meyerfin@hotmail.com

RE: Signal generator help	Reply
by WX7G on May 6, 2009	Mail this to a friend!
Do you have FM or AM modulation activated?

RE: Signal generator help	Reply
by WU0L on May 6, 2009	Mail this to a friend!
The AM modulation is turned off. There is no FM modulation control available as near as I can tell. Thanks for the help. Mark WU0L

RE: Signal generator help	Reply
by WB2WIK on May 7, 2009	Mail this to a friend!
Do you have a marker turned on? I don't know this model specifically, but most sweep generators can also produce a marker signal, so if you run with the marker on, it's producing two signals, at different frequencies, simultaneously. WB2WIK/6

RE: Signal generator help	Reply
by WU0L on May 8, 2009	Mail this to a friend!
The marker is turned off, so this is not the problem. Thanks for the suggestion. Mark WU0L

RE: Signal generator help	Reply
by KC9KEP on May 14, 2009	Mail this to a friend!
Mark, I went to the "Agilent" WEB page (Agilent owns the HP stuff) and looked under Test & Measurement, but it only tells me that the HP 675A is discontinued and they have no archived manual. They do provide a list of links that may have old manuals. Sounds like your unit is "stuck" maybe in a two-tone test mode? (I don't know the HP 675A). You should be able to set the starting and ending sweep frequencies and how radiply the generator sweeps from start to end. And, it should be "easy" to display on a scope .. i.e., you should see a sin wave that compresses & snaps back repeatedly :-) Sorry I can't offer more help ..

RE: Signal generator help	Reply
by WU0L on May 15, 2009	Mail this to a friend!
Thanks for the tips. Using your suggestion, I did observe the "sweep" affect between the start and stop frequencies. I can only get it to sweep once in the "auto", "manual" or "retrace" mode. I would think in the "auto" mode it would periodically sweep. Do you know what the "F/delta F" mode would be? The "delta" being represented by a triangle symbol on the dial. This is the control that has "Start/Stop", "F/deltaF", "CW", and "External Control" for modes. Then another control allows you to set the "delta F" to various kHz or mHz settings. I can observe no changes in output no matter where it set the "delta F" when in "F/delta F" mode. Gradually I am learning a few things about this machine, and also it seems to be coming to life a bit more as I keep it powered up. Probably it had been retired for a long time. Thanks, Mark WU0L

RE: Signal generator help	Reply
by KE4DRN on May 18, 2009	Mail this to a friend!
hi Mark, try the hp yahoo group, I'm sure you can find a pdf manual no cost. http://tech.groups.yahoo.com/group/hp_agilent_equipment/ 73 james

RE: Signal generator help	Reply
by WU0L on May 19, 2009	Mail this to a friend!
Thanks for a good idea. Mark WU0L

RE: Signal generator help	Reply
by W6IEZKEN on June 14, 2009	Mail this to a friend!
The Delta sign refers to the amount of change between two frequencies.The first could be 10Mhz and the second could be 15Mhz, so the unit would sweep between 10Mhz And 15Mhz.This is useful for determining bandwidth and shape factor in I.F.'s. or filters.A manual would be the best solution to your questions and keep in mind the reason you don't see a change when switching is that circuit may not be working.Get the main circuit working and then go to each sub-circuit function.A manual of any sweep generator from HP in that period of time will at least help you understand the functions even if there are differences.If you can't find a free manual you can buy one from the commercial manual suppliers for about $30.

Page 1 of 2 Next

Next Topic: VHF/UHF couplers - Homebrew help plse
Previous Topic: Modified 6BTV antenna

Email Subscription
You are not subscribed to this topic.

Check our help page for help using Forum, or send questions, comments, or suggestions to the Forum Manager.

$\'\'$