Hi Samuel, I suggest starting by downloading the component level information for the 53131A and 53132A from tha Agilent site at the following links.
http://cp.literature.agilent.com/litweb/pdf/5989-6308EN.pdf http://cp.literature.agilent.com/litweb/pdf/5989-6307EN.pdf The 53132A document includes a schematic of the channel C board with parts list and may assist in getting you started. Richard > Thanks for your answers. > > About the components, I think my first prototype will use some very > well-known prescaler and amplifiers like Hittite HMC363 and Mini-circuits > ERA-1SM, only to validate the design. I will use a 100 MHz high-pass filter, > but overall, it will be a wide-band, low-sensitivity design, exactly like > the original option. > > But before thinking about the best components to use for the amps and the > divider, we need to know how to interface the prescaler with the counter. > There is some very important questions to answer : > > - What's the divider ratio used ? Perhaps /16 for 3 GHz, /32 for 5 GHz, and > /64 for 12.4 GHz, but we really need to be sure. > - What's the gain of each one of the four amplifiers present ? > - How does the counter aware about the option used ? There is no > "intelligence" on the option board, so, the counter may detect the type of > prescaler with some pull-up or pull-down resistors somewhere. > - What is the exact pinout for the J2 connector ? > > In order to get an answer, we need to find somebody with a genuine option > board willing to spend an hour for the project... > > :-) > > > > -----Message d'origine----- > De : [email protected] [mailto:[email protected]] De la > part de Rick Karlquist > Envoyé : dimanche 15 février 2009 03:47 > À : Discussion of precise time and frequency measurement > Objet : Re: [time-nuts] DIY Frequency extension for HP Agilent 53181A, > 53131A or 53181A > > Max Skop wrote: >> Hi Samuel and all, >> Welcome to the group. >> I also have a 53131A and would welcome any way to enhance or upgrade the >> performance of this instrument. Please count me in on clone option parts. >> As can be seen from the picure of the 3Ghz option there is nothing special >> in its construction. Just four stages of amplification and a divider. > > In 1987, I was the project manager for the HP 5334B frequency counter. > In those days, we had a 1.3 GHz option called a "C channel". I > evaluated various off the shelf dividers at the time and built > some C channel boards very similar to the one you are describing. > It is actually very difficult to make a prescaler that really works > well using off the shelf dividers. The prescaler tends to be insensitive > to low frequencies. Attempting to fix this with a lot of gain > (4 stages!) has the problem that any wideband noise from the source > is also amplified. Off the shelf dividers are made to work in > frequency synthesizers where they have a clean signal from an oscillator. > They don't do well with general signals from noisy sources. > The HP 5386 used an HP made frequency divider that had "static" > flip flops instead of the "dynamic" ones in all the off the shelf > dividers. It is the only prescaler I am familiar with that actually > works well. The custom IC in it cost HP a fair amount just because it > was "home made" in the Santa Rosa fab, which was a money sink. > > If you want to build your own prescaler, you might not want to copy > the Agilent one. Unless you need the sensitivity, you would be > better off with less gain. Also, you should choose a divider that > works well at the frequency you want to measure. AFAIK, all OTS > dividers have an optimum frequency range, which varies from divider > to divider. > > When testing prescalers, the thing to watch out for is that the > lower order digits will bounce around. This is usually a symptom > of prescaler error, assuming that the source is stable. > > Rick Karlquist N6RK > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
