[time-nuts] HP 5334B C-channel--was Re: Which HP FrequencyCounter?

Roy Phillips phill.r1 at btinternet.com
Fri Mar 21 07:46:39 EDT 2008


Dider

Very interesting stuff regarding the HP 5334A/B, and I have asked Rick if he 
considers the "A" model to be worth picking up - I note that you have the 
"B" version - I have an "A" version in sight, but would you hold out for the 
"B", what's your opinion ?

Roy

----- Original Message ----- 
From: "Didier Juges" <didier at cox.net>
To: "'Discussion of precise time and frequency measurement'" 
<time-nuts at febo.com>
Sent: Friday, March 21, 2008 2:23 AM
Subject: Re: [time-nuts] HP 5334B C-channel--was Re: Which HP 
FrequencyCounter?


> Rick,
>
> Thanks for the interesting bit of history.
>
> I remember a previous post where you told us about the difficult choices 
> you
> had to make for the standard "reference" oscillator, which is certainly 
> not
> one of the strong point of the instrument. Mine is hooked up to a
> Thunderbolt GPSDO, so the oscillator is not used.
>
> Can you tell us the reasons why the standard (no C channel option) 5334B 
> has
> most of the parts needed for the C channel except for the counter and two
> Shottky packages?
>
> I understand even at $2 the MB506 may have been considered "expensive", 
> but
> there are 3 amplifiers (MMIC or BJT?) and a bunch of parts around for
> biasing and coupling, and of the two counters I have without option C, 
> they
> have all these parts already installed, except for the MB506 and the two
> Shottkys.
>
> It looks as if the 5334B was originally intended to have the C channel as
> standard, and then the marketing folks decided to make it an option after
> the boards were built, but the (two HP 5334B) counters I have are fairly
> recent, in the history of the product, so that scenario does not make much
> sense.
>
> I must add that I really like my 5334B, I have about a dozen counters here
> and the HP 5334B is the one that gets the job first, which is the reason I
> would like to add the C channel. That would eliminate one more reason to 
> use
> either one of the EIPs or the Advantest.
>
> Didier KO4BB
>
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com
>> [mailto:time-nuts-bounces at febo.com] On Behalf Of Richard
>> (Rick) Karlquist
>> Sent: Thursday, March 20, 2008 9:31 AM
>> To: Discussion of precise time and frequency measurement
>> Subject: [time-nuts] HP 5334B C-channel--was Re: Which HP
>> Frequency Counter?
>>
>> I was the project manager and chief EE on the HP5334B
>> project.  The 5334A had a C channel using an HP made divide
>> by 10 prescaler that had a factory cost of ~$100.
>> In the 5334B, I replaced this with the Fujitsu MB506 divide
>> by 8 prescaler, which cost something like $2.
>> The firmware was changed slightly to account for the
>> different modulus.  This is the ONLY difference in firmware
>> between the 5334A and 5334B counters.
>> I considered using the NEC uPB581/2 prescalers.  This class
>> of prescalers is based on "dynamic" flip flops, as opposed to
>> static ones.  These flip flops are only intended for
>> prescaling a clean signal from a local oscillator in a
>> synthesizer.  In a frequency counter application, they work
>> OK on a new clean signal, but will miscount on noisy signals.
>>  "Noisy" here refers to broadband noise, not close in phase
>> noise.  Prescalers are especially sensitive to low frequency noise.
>>
>> Now it can be told that we used to test all C channels in all
>> models with an HP8660 synthesizer.  This was not one of HP's
>> best designs, and it has a lot of broadband noise.  [The
>> designers of this unfortunate product redeemed themselves
>> with the 8662, one of HP's flagship products].  In order to
>> properly count the
>> 1.3 GHz signal from the 8660, it was necessary to use a high
>> pass filter to keep the 8660's broadband noise from
>> corrupting the measurement.  This was also the case for the
>> previous HP-made divide by 10 prescaler.
>>
>> I put a LOT of effort into evaluating various prescalers and
>> trying to put in mitigation measures such as rolling off the
>> low frequencies before they could get to the prescaler.  I
>> eventually decided that the task was hopeless with off the
>> shelf prescalers.
>>
>> At the same time, one of the other designers in the lab was
>> working on the 5386 counter, and naturally we compared notes.
>>  This counter used an HP-made static flip flop.
>> The FF used in the 5334A was made at the Santa Clara bipolar
>> silicon fab.  The FF used in the 5386 was made in the Santa
>> Rosa fab.  Whether it was the process or the circuit design,
>> the Santa Rosa FF was absolutely bullet proof.  It made error
>> free measurements of the lousiest signals.  The designer of
>> the 5386 delighted in finding new signals to measure and
>> inviting me to a "bake-off" to see who's counter did better.
>> Of course, I always lost these contests miserably!
>>
>> I would encourage owners of 5334B's w/o the C channel option
>> to consider trying modern static flip flops from vendors such
>> as Micrel and OnSemi, rather than installing the MB506.  You
>> can easily glue an SMT prescaler to the board upside down in
>> the footprint where the MB506 goes, and then connect the
>> "dead bug" with little wires to the MB506 connections.
>>
>> Rick Karlquist N6RK
>>
>>
>> Didier Juges wrote:
>> > The HP 5334A or B with the C channel option has a
>> sensitivity spec of
>> > -30dBm (from memory) up to 1 GHz or so. The C channel has 15mV rms
>> > sensitivity at 1 GHz.
>> >
>> > The C channel option is rare, but it only requires 3 parts
>> (a diviser
>> > and two dual-shottkys) and a connector (and a hole in the
>> front panel)
>> > to add it to a 5334B for instance. I have two 5334Bs (one
>> is broken)
>> > and both have the other parts required for the C channel except for
>> > these three. There is a socket for the diviser, the
>> shottkys have to be soldered in.
>> >
>> > The C channel input is activated on pressing the '9' key.
>> >
>> > Unfortunately, the MB506 diviser (Fujitsu) seems a little hard to
>> > find. If anyone has a spare, let me know. A surface mount
>> equivalent
>> > should not be too hard to put in.
>> >
>> > The HP 5316 has similar characteristics and also has a 1
>> GHz option,
>> > which is also rare.
>> >
>> > I also have an Advantest TR5823 counter which has the 1.3 GHz input
>> > with 20mV rms sensitivity at 1.3 GHz.
>> >
>> > The HP models have reciprocal counting, so they work MUCH
>> better for
>> > low frequency signals.
>> >
>> > Didier KO4BB
>> >
>> >> -----Original Message-----
>> >> From: time-nuts-bounces at febo.com
>> >> [mailto:time-nuts-bounces at febo.com] On Behalf Of Jean-Christophe
>> >> Deschamps
>> >> Sent: Saturday, March 08, 2008 10:49 AM
>> >> To: time-nuts at febo.com
>> >> Subject: [time-nuts] Which HP Frequency Counter?
>> >>
>> >> Dear group,
>> >>
>> >> I consider buying a used lab frequency counter / timer --preferably
>> >> HP/Agilent-- covering from few mHz to perhaps 400 MHz.
>> I'm worried
>> >> that models handling high frequencies seem to be limited
>> to under 100
>> >> mV input signal max. I don't want to destroy an input channel each
>> >> other day when calibrating/repairing some instrument.
>> Also are there
>> >> instruments with high impedance input? 50 Ohm is not quite
>> right for
>> >> investigation in the guts of most designs.
>> >>
>> >>
>> >> Is it possible to find a not-too-old model under $800?  I
>> would like
>> >> to find something in France or UK or Europe, but it seems
>> hopeless in
>> >> this budget.  I would favor a repairable model (with available
>> >> service docs & schematics).
>> >>
>> >> Your expert advises are more than welcome!
>> >>
>> >> --
>> >> <mailto:jcd at q-e-d.org>jcd at q-e-d.org
>> >>
>> >>
>> >> _______________________________________________
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