Hi, I used an HP counter in 1961 that had these vertical strings of neon tubes behind numbers, and the two least significant decimals were read off two milliamp meters numbered 0 to 10. For each count the needles would point to the number to be read. The whole instrument was a 2 foot cube that sat on a trolley. After all this time I can not remember the model number. Our company repaired Air force instruments and recalibration of frequency “meters” (calibrated heterodyne oscillators). Cheers, Neville Michie
> On 21 Jan 2019, at 13:44, Brooke Clarke <[email protected]> wrote: > > Hi: > > I think there were some versions prior to transistors. For example: > https://prc68.com/I/HPac4a.shtml > A friend of the family worked at HP and gave these to me. > > -- > Have Fun, > > Brooke Clarke > https://www.PRC68.com > http://www.end2partygovernment.com/2012Issues.html > axioms: > 1. The extent to which you can fix or improve something will be limited by > how well you understand how it works. > 2. Everybody, with no exceptions, holds false beliefs. > > -------- Original Message -------- >> Hello Time Nuts, >> >> Hopefully some of you will find this snapshot of HP's "Santa Clara >> Division", the home of Frequency Standards and Frequency Counters >> interesting. Send me a note if you want me to keep writing old HP stories. >> >> >> When I arrived at HP Santa Clara Division (SCD, Division 02, as in the >> second HP division ever) in 1984, the beginning of the end of the >> "frequency" business was starting to be felt. >> >> This product line dates to the 1950's with the invention of the first >> frequency counter. Breakthrough for its time, it enabled precision >> measurements of frequency, using "digital" techniques. The basic idea: >> Open a "gate" for 1 second, and count the number of positive zero crossings >> of a signal. The count was the frequency to 1Hz resolution. Longer gate >> times (10 seconds) would give more resolution, etc. This required the >> invention of fast digital counting circuits (essentially a chain of >> flip-flops, likely implemented with the very earliest discrete transistors), >> some binary to decimal conversion for the display, and there you have it: >> Something that can measure frequency. >> >> 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. >> >> With the reciprocal counter, it was essentially measuring a time interval >> (one period of the input signal), and calculating frequency. The obvious >> extension was an instrument to measure time intervals directly, using two >> inputs. Channel A to start and Channel B to stop. And the "Universal >> Counter" was born. >> >> All of these required an accurate frequency source to precisely open the >> gate, or to be counted in reciprocal counters or time interval measurements. >> This is what drove the market for PFS - precision frequency sources. A >> progression of improved quartz oscillators were invented, and then the >> cesium standards starting in 1965. Now, from HP you could buy it all: The >> perfect time base, and the high resolution counter. All your frequency >> measurement dreams supplied from wonderful HP. This was a great >> compliment to HPs frequency generator product lines. (Remember HPs first >> product in 1939 was the 200A audio oscillator.) A frequency counter, >> using a precision time base, was able to calibrate (or perhaps tune) an >> oscillator or frequency generator to create a complete system to generate >> very accurate signals. Lots of great applications for all of this. >> Growth, profits, happiness. I'll guess that the mid 1970's were the peak of >> the business. In 1984, SCD was a ~$100M business per year, with frequency >> counters being over half of it. (SCD also made laser interferometers, >> which was about ¼ of the business) >> >> But as the 1970s became the 1980s, things started to go flat. Frequency >> sources (Cesium standards, etc.) last for a very long time. Did everyone >> who needed one already buy one? We were also running out of new tricks to >> put into frequency counters. And they lasted for a long time too. New >> products were mostly just modern implementations of older models, with >> better computer interfaces for automated control, and cheaper to build. >> Every general manager knows that he'll never grow his business replacing >> older products with newer, but cheaper replacements. >> >> To make matters worse, the cold war was ending, and D.O.D. spending was >> slowing down. >> To make things still worse, the signal generators now were "synthesizers", >> and included their own precision time bases. No counter needed to measure >> the output. >> And even worse, digital oscilloscopes were getting better, and they measured >> frequency right on the front panel, to 3 or 4 digits. Which was often good >> enough. >> >> SCD needed a new trick. Divisions that don't grow become crummy places to >> work. Especially for upwardly mobile managers. A huge investment was >> made in "Sandblaster", which was wafer level IC tester. This lasted a >> couple of years and was cancelled. "Waveform Recorders" were also invented >> and brought to market. I think they were essentially a very deep memory >> digital oscilloscope, back when lots of DRAM memory was really expensive. I >> think Rick Karlquist worked on these for a bit. I don't think they really >> took off, and probably had a "charter war" conflict with the oscilloscope >> division in Ft. Collins(?) Colorado. >> >> 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. >> >> During the heyday of Modulation Domain Analyzers, HP would take promotional >> pictures for sales brochures. The photographer would sometimes grab a HP >> employees to be in the photo shoot. Jim Cole, now an inkjet engineer that >> I still work with was the model for the 5371A. I stumbled across his >> picture in the Keysight company history web pages. He had long forgotten >> it, and enjoyed seeing his younger self from 30 years ago. In about >> 1990, I was walking down the wrong hall one day, and offered a ham & cheese >> sub sandwich if I had a few pictures taken with the 53310A. This photo of >> me with the instrument was up in the lobby of the SCD building in Santa >> Clara for several years. A colleague rescued it from a dumpster during a >> renovation, and mailed it to me, as I had relocated to Vancouver WA. It is >> now proudly displayed on the ceiling of my shop. You can't see it this >> image, but the CD chosen by the photographer for the photo shoot always made >> me laugh: An album by "Twisted Sister". >> >> For a number of years, Modulation Domain analyzers really helped the >> business. I recall that the 5371 sold about 80 units a month, for about >> $25K each, or ~$2M of revenue a month. For a division with less than >> $10M/month revenue, this was a really big deal. A glimmer of hope for the >> division. We just needed to keep coming with more ideas like this. >> But this didn't come to pass. Modulation domain analysis, with all its >> novelty, just didn't need to be done that much. And digital oscilloscopes >> kept getting better. Slowly, sadly, precision frequency measurement was >> becoming a rarely needed thing, and there were already thousands of good HP >> counters out there that worked just fine. >> >> I was just down in the EE lab at my HP printer R&D site in Singapore last >> week, and found a 5314A and a 5315A counter on the shelf. The lead tech >> thought they were pretty cool, but it was obvious they hadn't been used in >> decades. I told him that I use to manage the engineering team that >> manufactured that product 30 years ago. In his polite Singaporean way, he >> acted impressed. >> >> HP growth was eventually found in other businesses (like inkjet where I went >> 25 years ago), and a colleague (John Flowers) that has stayed with Agilent >> and then Keysight said that Div 02, SCD was disbanded some many years ago. >> It was a great place to start my HP career 35 years ago, but time and >> technology has marched on and left it behind. >> >> Hugh Rice. >> >> >> >> >> >> >> >> >> >> >> >> >> _______________________________________________ >> 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. _______________________________________________ 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.
