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lothar baier
ok there are two basic ways to create a marker in a swept system, one is called RF blanking the other one is called intensity modulation, ok usually you have a control voltage thats proportional to your RF frequency, if the analyzer sweeps its basically a ramp, each point of the ramp corresponds to a certain frequency, you feed this signal to a comparator and compare it to a DC voltage thats adjustable (coming from your marker pot) anytime the ramp "hits" this threshold you get a pulse on your comparator output, you route this pulse back into your display and use it to crank up the intensity just a bit at this point and there you have a marker blip on your screen :) you could also use this pulse to turn the RF of your TG off for just a moment but then you would end up with a dark spot as a marker for a short time instead of beein brighter.
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Your statement about you seein a bright blip on your screen as a marker along with the statement about you seen the marker even with the calibator connected to your RF section input makes me certain that your markers are intensity modulated ! "David C. Hallam" <dhallam@...> wrote: -----Original Message-----
From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...]On Behalf Of lothar baier Sent: Friday, November 16, 2007 9:21 AM To: hp_agilent_equipment@... Subject: RE: [hp_agilent_equipment] Re: HP-8443A Tracking Generator Problems have you ever considered a 5345A ? they are cheap, and they go to 500MHz The marker does not really say anything, most of the time markers are blanked in on the sweep trace not on the RF level, i havent looked in the manual but thats how most generators and sweepers are doing it, the fact that you see a marker blip without the RF output of the generator beein connected to the SA input supports this. I don't understand this statement. I have the 8443A connected to the 141T SA system with the interconnect cable. Without this there would be no marker blip on the 141T screen. one possibility is to build a pre-scaler for your counter to extend the frequency range, the other one is that i could loan you a 500MHz counter so you can do the testing " Recent Activity a.. 7New Members b.. 6New Files Visit Your Group New web site? Drive traffic now. Get your business on Yahoo! search. Y! Messenger Send pics quick Share photos while you IM friends. Yahoo! Groups Going Green Share your passion for the planet. .. --------------------------------- Never miss a thing. Make Yahoo your homepage. |
