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

[Roy Phillips]

Rick

I am very interested in the exchange taking place with Dider Juges, 
regarding the merits of the HP 5334B, and its "C" channel, and the ?original 
"A" version. I currently own a 53131A with the 3 GHz  Channel 3 input, but I 
rather like the older HP products with their  quality build, ( I have a HP 
3456A Digital Voltmeter), and lets face it, they are in the main repairable. 
I am thinking of acquirring a 5334A   - or is it not as good as the "B" 
version. What 's your opinion ?
Roy

----- Original Message ----- 
From: "Richard (Rick) Karlquist" <richard at karlquist.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Thursday, March 20, 2008 2:31 PM
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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>>>
>>>
>>
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>>
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