[time-nuts] HP Stories: Frequency Counter business decline, Modulation Domain Analyzers, geeks as models

[paul swed]

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 <magnus at rubidium.se> 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
>
>
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