Have 4 HP5360s and even the keyboard and interconnecting cable. I did have to home brew a replacement Nixie assembly for one. (It was missing) I used orange/yellow 7 segment leds that matched the nixie filter very nicely. The same circuit produced an rs 2322 output. Way easier then the 1 MHz printer port. Regards Paul WB8TSL
On Tue, Jan 22, 2019 at 1:01 AM Magnus Danielson <[email protected]> wrote: > Hi Hugh, > > Enjoying your stories. > > On 2019-01-21 01:57, Rice, Hugh (IPH Writing Systems) wrote: > > Like all breakthrough measurements, the next 20+ years was spent > refining the concept. Better "front end" amplifiers, able to measure low > amplitude signals. Faster counters, that could capture higher frequency > signals. Microwave front ends, to either divide the signal by 8 or 16 or > whatever before being counted, or using some other down conversation > technique. Somewhere in the early 1970's (guess), the reciprocal counter > was invented. Rather than open the gate for 1 second, use the input > signal to open the gate for one period, and count a very high frequency > time base instead. It was much faster, and for lower frequency signals, > much much higher resolution. Now, if you had a ~1KHz unknown signal, > rather than only getting 4 significant digits in a one second measurement, > if you counted a 100MHz time base for 1 millisecond, you would 5 digits of > resolution. Open the gate for a thousand cycles, and 8 digits of > resolution were available. > > The HP5360A calculating counter was the first reciprocal counter that I > know of, released in 1970. > > The reciprocal counter principle can be found described in HP AN200: > > http://www.hpmemoryproject.org/an/pdf/an_200.pdf > > > The premium universal counter in the early 1980's was the 5370A/B. It's > specialty was extremely high precision time interval measurements, with > resolutions down to 20 pico seconds. An idea was made to extend the > time interval measurement into continuous real time, and measure dynamic > time intervals, as a function of time. HP called this "Modulation Domain" > analysis. I think that David Chu, one of the senior scientists at SCD in > the 1970s and 1980s was a key inventor of this. The 5371A was the > outcome of this work. It was followed by the 5372 and 5373. There > also was a lower cost version call the 53310 ("Stonehenge"?). The > measurement was novel and unique. You all know what oscilloscopes and > spectrum analyzers do, but this was a new spin: You could look at the > phase of a signal as a function of time. > > David Chu is a good name as one search for HP patents. > > The really shining details about the 5371 series of products is that the > event rate can be up to 10 MHz or 13,3 MHz depending on mode. The > resolution is 200 ps. I think the main step with the 5372A was the > hardware histogram, that would accumulate histograms faster than the CPU > would. You would need to adhere to some limitations, but gets much > higher speeds and hence higher amount of counts in return. For the type > of applications it was intended, it was a huge step forward. > > We still operate a 5372A in the lab. > > Thanks again for a nice tale. I just wanted to add a few comments that > may be useful. > > The HP Application Notes is always rewarding, just as the old HP Journal > numbers. > > Cheers, > Magnus > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
