What is a frequency counter and how to choose a ... - LinkedIn

What is a frequency counter? Frequency counters accurately measure the frequency of signals with waveforms such as sine waves, square waves, triangle waves, sawtooth waves, or other regularly repeating patterns. These instruments can measure the frequency and timing characteristics of both analog and digital signals. Do you need a frequency counter? Frequency Counters vs. Oscilloscopes and Other Devices: Other instruments, such as oscilloscopes, spectrum analyzers, and frequency meters (like old analog pointer meters), can also measure frequency. However, frequency counters excel in their precision and accuracy. While other instruments measure frequency and other characteristics from digitized data using software, frequency counters use carefully designed hardware circuits to accurately measure these parameters directly on the input signal. In addition, keep the following in mind when selecting an instrument:

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1. Frequency counters provide high-precision and high-resolution measurements, even at frequencies up to GHz.

2. Frequency counters work better with continuous wave signals; software-based measurements work better with pulsed signals.

3. Frequency counters can be used reliably for long-term frequency measurements.

4. Frequency counters are simpler and faster to use than oscilloscopes or spectrum analyzers. Frequency counter types by function The main classification method is based on the target industry and function.

Universal counters: Many customers prefer an all-in-one universal counter over a simple frequency counter because, in addition to supporting frequency measurements, it also has common auxiliary measurement functions, such as signal timing measurements. It can usually measure:

Frequency: refers to the number of complete cycles completed per unit time.

Period: refers to the time interval between a complete cycle of a signal.

Frequency ratio: used to measure the frequency ratio of two input signals.

Time interval: measures the time delay between two input signal events.

Time interval error: measures the timing variation relative to the expected or ideal value.

Pulse width: measures the duration of a pulse, usually the duration of a digital signal’s high level.

Rise and fall time: refers to the time it takes a digital signal to transition from a low state to a high state and from a high state back to a low state.

Phase angle: measures the phase difference between two input signals.

Duty cycle: refers to the percentage of a signal (usually a square wave) that is high in one complete cycle.

Voltage: reports the maximum, minimum, and peak-to-peak voltages of a signal.

Signal power: Some universal counters have built-in power meters that can report signal power.

In addition, these instruments support more advanced statistical and analytical functions, such as:

(1) Plotting histograms to view the distribution of frequency measurements and detect stability or noise issues.

(2) Plotting frequency trend graphs to detect problems such as frequency drift.

(3) Counting frequency measurements to detect signal jitter.

(4) Accumulating frequency readings.

(5) Calculating Allen deviation to measure frequency stability.

RF counters: RF counters, also known as microwave frequency counters, are widely used in RF engineering. They can measure frequencies ranging from a few kilohertz (kHz) to hundreds of megahertz (MHz) and even up to tens of gigahertz (GHz). For example, the Keysight A Universal Counter/Timer has a measurement limit of 350MHz for the basic model, while the advanced model can measure up to 15GHz. RF counters are constructed differently because digital circuit elements (such as triggers) are too slow to keep up with the high-speed switching of GHz-band radio signals. Therefore, RF counters use prescalers or other frequency reduction components to first reduce the frequency of the input signal to the MHz range.

Counting timers: These counters, also known as time interval analyzers, are optimized for accurately measuring time intervals.

Modulation domain counters: These counters are specifically designed to analyze modulated signals, in which the carrier signal is periodic, but this periodic pattern is masked by the frequency modulation scheme.

Frequency counter types based on appearance

Frequency counters can also be divided into the following types based on appearance and interface:

Benchtop instruments

Handheld instruments

Hardware modules for modular test equipment

Embedded modules for ASICs

Logic modules in FPGAs

Which industries use frequency counters?

Different types of frequency counters are used wherever high-precision frequency and timing measurements are required, which is the case in the following industries.

Electronic Component Manufacturing: Accurate frequency and timing measurements are essential for quality control of several electronic components such as oscillators, phase-locked loops, clock modules, analog-to-digital converters, timer circuits, dividers, etc. In these industries, frequency counters are used as test equipment.

Defense: RF counters are used for quality control of critical radar and sonar systems.

Global Navigation Satellite System (GNSS): GNSS satellite constellations like the Global Positioning System rely heavily on precise timing and frequency characteristics.

Telecommunication Systems: Similarly, in wireless communication equipment such as 5G base stations, frequency counters are used to achieve precise timing and frequency characteristics.

How a Frequency Counter Measures Frequency

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Frequency refers to the number of complete cycles a signal completes per unit time. There are two main methods for measuring frequency.

Direct Frequency Measurement Technique: The first method is called direct frequency measurement technique, which simply counts the number of cycles completed in a fixed time interval (called gate time). Here is how it works: A high-precision clock called a time base is responsible for gating, that is, measuring the number of cycles completed in a fixed gate time interval. It then divides the measured number of cycles by the gate time to get the frequency. There are some obvious disadvantages to this method: the gate time does not necessarily coincide with the signal period, which may lead to inaccurate cycle number measurement; for low-frequency signals, each cycle may last for a long time, and the counter needs to set a long gate time to accurately measure the number of cycles.

Reciprocal measurement technique: Another better method is the reciprocal measurement technique. Unlike the direct frequency measurement technique, the reciprocal measurement technique does not count the number of cycles completed within a fixed gate time, but waits for a fixed (internal configuration) number of cycles to complete, and then uses a high-precision internal or external time base to accurately measure the time required to complete these cycles. This time is the gate time. Finally, it calculates the frequency by dividing the number of cycles by the measured gate time. It is called the reciprocal measurement technique because it first measures the time of each cycle and then takes its reciprocal to calculate the frequency. The advantages of the reciprocal measurement technique include: the same number of bits of frequency resolution can be obtained regardless of whether the input frequency is hertz or gigahertz; it has high accuracy at both very low and very high frequencies. However, frequency counters using the reciprocal measurement technique are more expensive to manufacture.

What are the key components of a frequency counter?

The high accuracy of a frequency counter is due to its components, which are listed below.

Precision Timebase: The timebase is an internal clock and gating circuit used to accurately measure periods or timing, depending on the measurement technique. It is usually one of the following crystal oscillator circuits:

Room Temperature Crystal Oscillator: Uses a simple quartz crystal that maintains a fairly stable frequency at room temperature and is suitable for non-critical applications.

Temperature Compensated Crystal Oscillator: Maintains a stable frequency by compensating for temperature fluctuations caused by operating conditions or environmental changes.

Oven Controlled Crystal Oscillator (OCXO): Also known as a high stability oven timebase, this oscillator is placed in a small oven to achieve high stability and accuracy by maintaining a constant temperature. The timebase is susceptible to timebase errors caused by aging and temperature effects. Meticulous maintenance and regular calibration are necessary to maintain the highest stability and accuracy over the long term.

Input Amplifier, Attenuator, and Prescaler: These components are used to condition the input signal to match the counter circuit. They can amplify weak signals, attenuate strong signals, block high-frequency noise, and achieve impedance matching. RF counters must ensure that high input signal frequencies are reduced so that downstream digital circuits can keep up with the signal’s transition speed. For this reason, they use high-speed prescalers, transmission oscillators, or heterodyne converters.

Trigger or comparator circuit: The trigger circuit is used to accurately determine the start and end of each cycle of the input waveform.

Counting circuit: This circuit is where the actual cycle counting and time measurement takes place. It consists of digital logic circuits, including components such as flip-flops and NAND gates, which are activated each time the input signal exceeds the trigger level.

Microprocessor: The microprocessor is used to control the operation of the frequency counter, store and transmit data, perform statistical and other analysis, and communicate with the user or other devices.

Power supply: The frequency counter uses a high-quality power supply with very low ripple and noise.

Interface circuits and external interfaces to other devices: Most modern frequency counters can be connected to personal computers and automated test equipment through the following input/output interfaces:

General Purpose Interface Bus (GPIB): This is a hardware and data exchange standard for connecting programmable instruments to computers. It includes the Standard Commands for Programmable Instruments (SCPI), which specifies a set of commands and semantics for each type of instrument.

Universal Serial Bus (USB): The frequency counter can transfer measurement data to a USB storage device.

RS-232: This serial bus can be used to transfer data to a computer in a custom binary format.

LAN Extensions for Instrumentation (LXI-C): This is an Ethernet-based SCPI protocol that supports browser control of the instrument.

Display Circuitry: If the frequency counter is a stand-alone instrument, it is usually equipped with a liquid crystal display (LCD) and display circuitry to display measurement results, analysis results, and graphical outputs such as histograms.

What are the key specifications of a frequency counter?

When selecting a frequency counter, the following key specifications are important to look at:

Number of input channels

Frequency range and maximum frequency for each channel

Frequency resolution, the number of digits that indicate the accuracy of the frequency measurement

Time resolution, the smallest time difference between two events that can be measured in a single measurement, usually in nanoseconds or picoseconds

Phase resolution, in degrees

Time base error, time base aging factor (in ppm or ppb per year), and time base uncertainty

The rate at which data is transferred to an external interface

Tips for achieving high precision and accuracy

Follow these tips to make precise measurements with a frequency counter:

Avoid using the automatic trigger mode, which has low accuracy. Using other trigger modes, such as external trigger, time trigger, or digital trigger, can improve time resolution and system uncertainty, thereby reducing overall measurement error.

Always keep the time base powered on so that it is in a warm-up state. This can improve the annual aging rate by an order of magnitude compared to periodically powering it off.

Use the best time base possible. High-stability, temperature-controlled time bases do not require frequent calibration, but for time bases with poor stability, regular calibration is recommended.

Pay attention to trigger level and trigger level timing errors, especially when the signal is noisy.

Lock all time bases to the same clock to avoid signal jitter caused by independent time bases.

Set the trigger level so that it intersects the signal at the point where the signal slope is the largest to minimize the response time of the trigger condition.

Do not set the trigger bandwidth too narrow to prevent noise from being misinterpreted as a zero crossing.

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devanno

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Universal Counter Suggestions / thoughts

« on: January 09, , 08:15:05 pm » I posted this at the end of an old thread... thought I'd start a new one in case people didn't see the ancient one. :-)

Getting back into the study of electronics after a long hiatus, I am building a test bench for both education and design / repair of "stuff."  It's been noted that the built-into other devices counters aren't always ideal, so I'm looking to add a "universal counter" to my bench.  I realize that these two are not exactly in the same range, but I'm looking at the BK Precision A (which some have indicated that they're quite happy with) and the TTi TF960 (ok, so the 930 would be a better comparison, but if I'm in for that much, might as well go for a bit of gusto).  I am just curious if anyone here has some good insight on these?   TIA...D

P.S.  The other reason I need a universal counter is that I only have 8 fingers and two thumbs, but sometimes, I'm all thumbs. :-)

Free Electrons - Just one, please.

PaulAm

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Re: Universal Counter Suggestions / thoughts

« Reply #1 on: January 09, , 08:42:15 pm » Possibly the ultimate was an HP with a replacement CPU card running Linux.  It ran a emulation, firewall, webserver, etc etc and was tons faster than the original.  It was a pretty neat project.

The original A and B had pretty good specs (20 pS resolution!)  but it really sang with a modern processor.  That counter cost $25K when it came out.

If you search the time-nuts mail archive for " processor board", you'll get the thread.  I'd post the link, but his site does not seem to be up anymore.  Pity that.

BloodyCactus

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Re: Universal Counter Suggestions / thoughts

« Reply #2 on: January 09, , 08:48:55 pm » i have a racal dana I got off ebay for $100 thats fantastic. ovenised oscillator, its a+b inputs can do like 120 or 200mhz and its c input can do 1.5ghz. very sweet piece of kit for 100$ I think its 9 digit plus overflow -- Aussie living in the USA --

kwass

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Re: Universal Counter Suggestions / thoughts

« Reply #3 on: January 09, , 09:36:52 pm »

i have a racal dana I got off ebay for $100 thats fantastic. ovenised oscillator, its a+b inputs can do like 120 or 200mhz and its c input can do 1.5ghz. very sweet piece of kit for 100$ I think its 9 digit plus overflow

I second this.  I got mine off ebay 15 years ago with the 04E oscillator option (high-stability overized oscillator) for about $150.  It's worked perfectly, although some people have had problems with the buttons (search this forum for solutions) I have not.

It's has a 9 digit large LED display but it can overflow and still run, giving you effectively 10 digits.  It's also very flexible once you learn the somewhat quirky way to set options from the front panel.
-katie

babysitter

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Re: Universal Counter Suggestions / thoughts

« Reply #4 on: January 09, , 10:26:52 pm » Having a HPA I could give you some insight about that... but what are you looking for ? That info really counts (literally!))
I'm not a feature, I'm a bug! ARC DG3HDA

G0HZU

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Re: Universal Counter Suggestions / thoughts

« Reply #5 on: January 10, , 01:21:42 am » Generally speaking, a new and fairly expensive frequency counter isn't something that would be high on the list of priorities for most people. I have never spent more than £80 on a counter and I don't use my counters very often these days. However, I can comment on the two counters you listed....

The TTi uses an LCD display (backlit) and I would suggest you check it out to see if you can live with an LCD display. I prefer counters with a big/bright LED display that can be casually read at an angle at a distance. But that's just me...

Both of the counters offer remote logging. One is RS-232 and one is USB. I do think this could prove a useful feature if you wanted to log the drift of something over time.

But here is a slight problem with both of these reciprocal counters... Compared to older/used/cheaper high end instruments they are both slow in terms of measurement/display time for a 9 digit display. eg 10 seconds measurement time?  So you could only get (fresh) data at this resolution every 10 seconds.

This is fine for most applications but I'd be seriously pissed off if I'd spent £400 on a new/modern counter that was this slow.

For home use most people would be better off buying something like an old Racal reciprocal counter/timer for a fraction of the price (but it will be just as slow) although I would try and get one with GPIB for logging. But a lot depends on what you plan to do with the counter. « Last Edit: January 10, , 01:49:00 am by G0HZU »

devanno

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Re: Universal Counter Suggestions / thoughts

« Reply #6 on: January 10, , 04:56:24 am » Thanks all for the quick replies.  I was looking on eBay, actually, and perhaps wasn't looking closely enough.  :-)  I really appreciate the thoughts and input!!!

As for the -exact- use, I'm not 100% sure yet.  Mostly doing some self education and assembling a bit of decent kit while I can afford it.  I'm kind of front ending the funding of some "hobby" items in my retirement. 

Again, many thanks! Free Electrons - Just one, please.

Vgkid

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Re: Universal Counter Suggestions / thoughts

« Reply #7 on: January 10, , 05:17:03 am » I'll echo babysitters response, and say that the A is another contender. If you own any North Hills Electronics gear, message me. L&N Fan

oldway

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Re: Universal Counter Suggestions / thoughts

« Reply #8 on: January 10, , 08:19:41 am » I have an HPA with options 001 (TCXO) and 003 (C channel 50 to Mhz) and I am very satisfied with it.

Re: Universal Counter Suggestions / thoughts

« Reply #9 on: January 10, , 08:32:52 am » I recon this Philips one is a good buy, it's a really nice bit of kit:
http://www.ebay.com.au/itm/PM-PHILIPS-HIGH-RESOLUTION-PROGRAMMABLE-TIMER-COUNTER-225MHz-/
Only the standard internal oscillator though.
They usually go for much more than this.

Re: Universal Counter Suggestions / thoughts

« Reply #10 on: January 10, , 08:35:36 am » Also the Philips is great small size unit.
Once again, if you can get one at a decent price with an oven oscillator then it's a good score.

engiadina

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Re: Universal Counter Suggestions / thoughts

« Reply #11 on: January 10, , 09:20:55 am » Let me add the HP a with at least option 001 (mid stability oszillator).

You might eventually find this for a decent price.


From my own experience go for HP, Phlips/Fluke, Racal
I checked a Hameg counter ... guessing would gave been more exact. Timebase stability was atrocious.

Guido

babysitter

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Re: Universal Counter Suggestions / thoughts

« Reply #12 on: January 10, , 01:41:24 pm » Help us a little bit:

Do you want to count frequencies above what you can use a scope for, or do you want way higher resolution that possible with peak-counting on the scope?
Do you want to measure one or several events that are too slow for convenient o-scope-peak-counting?
Do you want to log frequencies or time-intervals?

If you answer at least one of those with yes, then go for Universal counter.
Consider using a wide-band radio receiver as an alternative for high frequency stuff, you might be able to listen into your signal. Google for SDR dongle.

If you want to do digital stuff, consider a Logic analyzer (OpenBench LA for example), you can read the frequency and time intervals with that device, too.

If you want the convenience of connect to DUT and read frequency, go for Unicounter.

You should be able to get decent offers on ebay or other places where cleanout of labs appear, at a nearby ham radio swap I saw the younger brother of mine recently, the HPB.

If you only want frequency reading, a simple frequency counter is enough, a universal counter will help if you want to compare frequencies or have exotic trigger/arming requirements for example.

About everything you can do with a UC you can do with other stuff, e.g. adjusting the LO of a radio to a known good source of LO Frequency ? Wideband radio, Lissajous method on cheaposcope are available too. But without the convenient number readout.

I like my Box A, but there are other from HP and there are also other manufacturers of course who make decent rigs.

What upper frequency limit do you look for ?

Check your space constraints, means check what fits best on your desk.

Get the manuals matching the offers on ebay for example from KO4BBs website, compare specifications.
A bad mother oscillator is not a no-go - you can replace it with something better.
A defect box is always a gamble, mine had defect not listed but was way cheaper than the others.
"only" had series resistors in input stages burnt, easy to replace. Mother oscillator seems to have been a Hameg , so I stuck a OCXO from ebay in it. Works like a charm.

« Last Edit: January 10, , 01:44:59 pm by babysitter » I'm not a feature, I'm a bug! ARC DG3HDA

jpb

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Re: Universal Counter Suggestions / thoughts

« Reply #13 on: January 10, , 03:04:37 pm » I have the TTi TF930 which I bought as an ex-demo unit for £200.

The reasons I went for it was I wanted 10 digits and I wanted a counter that would go down below 1 Hz and have a reference input so I could stick my 10MHz reference on the reference input and measure the 1pps from a GPS module and then tune my 10MHz source.

For this purpose the TTi TF930 works well. Other pluses are it is a continuous reciprocal counter (i.e. it doesn't reset itself between readings but continues to count), it is very light and low power so it can operate from USB or from its internal batteries and it is very easy to carry around.

The negatives are the LCD display isn't even backlit so is not easy to see in some conditions and it is a bit slow if you want the full 10 digits (i.e. you need to set the 100 second gate).

As others have said, you can get good 8 digit or 9 digit counters with bright displays more cheaply on e-bay which are probably a better choice for direct frequency measurement. I personally didn't go for these because they tend to have a minimum frequency of several 10s of Hz and I already have 6 digits on my scope counter so I wanted a significant step up from this.

What I'd really like is one of top-of-the-line Agilent series at 12 digits a second and 20 psec resolution but these are ten times the price even second hand.

EDIT: another negative, which rather annoys me, is that the 10MHz reference input requires quite a high amplitude (at least 1Vrms I think) to be recognized so I had to build a little video amp just to get my 10MHz OCXO to become a reference source and you can't take the reference output of  say the Agilent A and feed it straight into the reference input of the TTi. There is also no reference output so it is difficult to daisychain.

Another plus though is that it can be connected to a computer for logging readings and so on, but I've only managed to do this successfully using a dumb terminal on a Windows XP laptop - I've not yet managed to get it talking to my Windows 7 64bit workstation. I've not tried for a while though, TTi may have produced an updated driver. « Last Edit: January 10, , 03:16:39 pm by jpb »

devanno

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Re: Universal Counter Suggestions / thoughts

« Reply #14 on: January 10, , 04:36:18 pm »

Help us a little bit:

Do you want to count frequencies above what you can use a scope for, or do you want way higher resolution that possible with peak-counting on the scope?

Higher resolution, easier to set up or to use when I need the 'scope(s) for other measurements

Quote

Do you want to measure one or several events that are too slow for convenient o-scope-peak-counting?

A definite possibility.

Quote

Do you want to log frequencies or time-intervals?

Unsure at this juncture.

Quote

If you answer at least one of those with yes, then go for Universal counter.

Thanks!  You just confirmed my thinking! 

Quote

Consider using a wide-band radio receiver as an alternative for high frequency stuff, you might be able to listen into your signal. Google for SDR dongle.

Oh... now that's a cool thought!  Will keep this in mind.

Quote

If you want to do digital stuff, consider a Logic analyzer (OpenBench LA for example), you can read the frequency and time intervals with that device, too.

I have a USB logic analyzer that will work for now.


Quote

You should be able to get decent offers on ebay or other places where cleanout of labs appear, at a nearby ham radio swap I saw the younger brother of mine recently, the HPB.

Am currently eyeing an HPA with the OCXO at the moment.  A bit pricey, but I like the OCXO option, and I think the extra few bucks is worth the time stability.  I may also want to use the output from that XO as input to other instruments for some tests, just to insure that all are on the -same- time base.

Quote

If you only want frequency reading, a simple frequency counter is enough, a universal counter will help if you want to compare frequencies or have exotic trigger/arming requirements for example.

About everything you can do with a UC you can do with other stuff, e.g. adjusting the LO of a radio to a known good source of LO Frequency ? Wideband radio, Lissajous method on cheaposcope are available too. But without the convenient number readout.

I like my Box A, but there are other from HP and there are also other manufacturers of course who make decent rigs.

What upper frequency limit do you look for ?

Check your space constraints, means check what fits best on your desk.

Get the manuals matching the offers on ebay for example from KO4BBs website, compare specifications.
A bad mother oscillator is not a no-go - you can replace it with something better.
A defect box is always a gamble, mine had defect not listed but was way cheaper than the others.
"only" had series resistors in input stages burnt, easy to replace. Mother oscillator seems to have been a Hameg , so I stuck a OCXO from ebay in it. Works like a charm.

So.. not sure what upper Freq I'll eventually need, but for now, 200MHz will do.  I was only looking at the higher priced spread because if I was going to buy new, I was just going to go for "one."   All the great replies here forced me to do more research on eBay.  Oh, and I have the manuals downloaded for the HPA/B and the HP already, too.

Thank you once again! Free Electrons - Just one, please.

devanno

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Re: Universal Counter Suggestions / thoughts

« Reply #15 on: January 10, , 04:38:23 pm » JPB ... thanks for that review.  I guess I missed the "no backlight" part, and that's likely a killer for me on that unit.  Looking now at an HP A with OCXO on eBay.

To all:  thank you, thank you, thank you!  You've really got me pointed in what I think is the right direction here! Free Electrons - Just one, please.

G0HZU

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Re: Universal Counter Suggestions / thoughts

« Reply #16 on: January 10, , 06:06:07 pm » Quote

You've really got me pointed in what I think is the right direction here!

Are you sure about that?

The HPA is a huge thing and I wouldn't have one of these counters even for free simply because it takes up too much space for what it can offer me in return. I'm guessing it has a fan (so it would also be noisy and annoying to use) and presumably it takes a fair bit of power as well. It's the kind of thing that appeals to timenuts who don't care how much space or power it needs or how noisy and annoying it is to use because it has a high spec and lots of digits. That's all that matters to them.

Something like the little Racal /2 that was mentioned earlier is fairly small and can be easily stashed out of the way when not in use. I have an old Philips PM 1.3GHz reciprocal counter/timer here with the dreaded LCD display but it is a far better choice compared to the big old HP as long as you can live with 8 digits per second measurement time (or 9 digits per 10 seconds). It is a nice little compact unit that can be moved around easily from room to room or shelf to bench or you can plonk it on top of something easily.

Try to do that with an HP... 
« Last Edit: January 10, , 06:25:49 pm by G0HZU »

orin

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Re: Universal Counter Suggestions / thoughts

« Reply #17 on: January 10, , 07:22:17 pm » A will give 9 1/2 digits in less than 2 seconds.  It plonks down fine on top of an A spectrum analyzer   And also supports the laptop that sits on top of it...

However, a A will likely need a little work.  See the service note I posted in a different thread.  If it has the AC fan, you'll want to replace it with a 24V DC fan as per the service note (plenty of 24V 80mm x 80mm fans out there to chose from).  If it already has the DC fan and the wiring described in the service note has not been done, you'll want to replace the relay socket and do the extra wiring or one day, you'll turn it on, the fan will run, but there will be no display.

orin

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Re: Universal Counter Suggestions / thoughts

« Reply #18 on: January 10, , 07:30:41 pm »

Possibly the ultimate was an HP with a replacement CPU card running Linux.  It ran a emulation, firewall, webserver, etc etc and was tons faster than the original.  It was a pretty neat project.

The original A and B had pretty good specs (20 pS resolution!)  but it really sang with a modern processor.  That counter cost $25K when it came out.

If you search the time-nuts mail archive for " processor board", you'll get the thread.  I'd post the link, but his site does not seem to be up anymore.  Pity that.

It's working for me:

http://www.jks.com//.html

Also:

https://github.com/jks-prv/_proc

I don't know if there are still boards available.

G0HZU

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Re: Universal Counter Suggestions / thoughts

« Reply #19 on: January 10, , 07:54:17 pm » Quote

A will give 9 1/2 digits in less than 2 seconds.

Some of the little Racal reciprocal counters will do 9 digits per second and they are a tiny fraction of the size of that big old monster from HP.

I have an old japanese counter here (mid s vintage) that is even faster and it only cost me £65 and has a smaller front area than the Racal. The HPA is a big old thing that is best suited to diehard timenuts who will probably only ever feed it a 10MHz signal from their various references (whilst keeping a box of tissues handy).

There are far more practical and realistic choices for the typical person who just wants to do a few repairs and learn some electronics. But I suspect my advice will go unheeded. It usually does on this forum 

« Last Edit: January 10, , 07:56:53 pm by G0HZU »

bingo600

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Re: Universal Counter Suggestions / thoughts

« Reply #20 on: January 10, , 11:03:19 pm »

Possibly the ultimate was an HP with a replacement CPU card running Linux.  It ran a emulation, firewall, webserver, etc etc and was tons faster than the original.  It was a pretty neat project.

The original A and B had pretty good specs (20 pS resolution!)  but it really sang with a modern processor.  That counter cost $25K when it came out.

If you search the time-nuts mail archive for " processor board", you'll get the thread.  I'd post the link, but his site does not seem to be up anymore.  Pity that.

Try
http://www.jks.com//.html


I have one 

Ohh ...
And a Racal , and a PMB and .... 

/Bingo « Last Edit: January 10, , 11:07:33 pm by bingo600 »

G0HZU

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Re: Universal Counter Suggestions / thoughts

« Reply #21 on: January 11, , 12:16:31 am » How about this HPA on youtube.



Check out the loud buzzing noise from the worn out fan (especially at 3:57 onwards  )

It's a big old ATE counter designed to be put in a rack where humans don't tread or listen to the rack noise or have to put up with that hideous user interface. It's mainly meant to be remotely controlled by a computer in an ATE rack system and not sat in someone's bedroom measuring the clock frequency of an Arduino board or a typical ham/CB radio.

Maybe I should try a bit of reverse psychology and recommend that somebody who doesn't yet know why they need a counter or what they will use it for should always buy the biggest, noisiest counter they can find with 12 display digits and the most complicated and badly planned user interface. It should also weigh about 5 times more than a regular counter, consume at least ten times as much power as a regular counter (so they can enjoy having it on all day in a small room in the summer?) and it should be about 35 years old and fairly unreliable and should take up a huge and deep area of the workbench. Then they can sit back and enjoy... « Last Edit: January 11, , 12:21:29 am by G0HZU »

devanno

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Re: Universal Counter Suggestions / thoughts

« Reply #22 on: January 11, , 06:15:57 am »

How about this HPA on youtube.



Check out the loud buzzing noise from the worn out fan (especially at 3:57 onwards  )

It's a big old ATE counter designed to be put in a rack where humans don't tread or listen to the rack noise or have to put up with that hideous user interface. It's mainly meant to be remotely controlled by a computer in an ATE rack system and not sat in someone's bedroom measuring the clock frequency of an Arduino board or a typical ham/CB radio.

Maybe I should try a bit of reverse psychology and recommend that somebody who doesn't yet know why they need a counter or what they will use it for should always buy the biggest, noisiest counter they can find with 12 display digits and the most complicated and badly planned user interface. It should also weigh about 5 times more than a regular counter, consume at least ten times as much power as a regular counter (so they can enjoy having it on all day in a small room in the summer?) and it should be about 35 years old and fairly unreliable and should take up a huge and deep area of the workbench. Then they can sit back and enjoy...

      All I can say is that I will not be in a quiet environment most of the time... my shop is in the "mechanical room" in my basement with the water heaters, furnace, sump pumps, etc.  It's dry, but it's not quiet.  Since I'm old and getting hard of hearing, no problem there!  :-)   Seriously, though, one side of my bench is 18" deep shelves... the horizontal space is not so much of an issue, and I can replace fans.  I wonder if that guy in the You Tube video had baseball cards stuck to the fan with clothes pins.  (You have to be old, and possibly from the US of A to get that one, sorry.)  That unit is in definite need of some TLC for sure.  As for kludge interfaces, heck, I spent over 42 years in information technology... I've seen, learned and worked with my share.   This isn't a done deal, and I appreciate your thoughts and input. Free Electrons - Just one, please.

devanno

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Re: Universal Counter Suggestions / thoughts

« Reply #23 on: January 11, , 06:18:16 am »

A will give 9 1/2 digits in less than 2 seconds.  It plonks down fine on top of an A spectrum analyzer   And also supports the laptop that sits on top of it...

However, a A will likely need a little work.  See the service note I posted in a different thread.  If it has the AC fan, you'll want to replace it with a 24V DC fan as per the service note (plenty of 24V 80mm x 80mm fans out there to chose from).  If it already has the DC fan and the wiring described in the service note has not been done, you'll want to replace the relay socket and do the extra wiring or one day, you'll turn it on, the fan will run, but there will be no display.

Thanks for the heads-up on the service note.  I'll search for it.    Free Electrons - Just one, please.

G0HZU

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Re: Universal Counter Suggestions / thoughts

« Reply #24 on: January 11, , 03:04:54 pm » At the end of the day only you can decide what is right for you

I can only offer general advice. That A counter would typically have been used by a manufacturer of time/frequency related
products in a test/dev area where it could have been used for things like critically analysing the performance of new OCXO or clock generator designs over temperature, time and shock/vibration. eg it would have been used to gather critical performance data over the course of hours/days/weeks using an automated system. presumably the results of this would make their way onto the manufacturer's datasheet for the OCXO when it gets released for production/sale.

Maybe you feel you have a need for this level of performance but the advice I can offer is to 'not' be seduced by the performance it offers because it comes at the price of size, weight, power, reliability, ease of use and ease and cost of maintenance.

Measuring frequency (accurately?) beyond about 8 or 9 digits doesn't really add much value for the vast majority of professional or hobby users.

If you do buy it then it's worth finding out how long it takes for the OCXO to warm up and also if it stays hot in standby. I would assume it does stay hot in standby. My old Anritsu counter has a huge and very expensive Toyo OCXO inside it and it takes about 50 minutes to stabilise. This is a major PITA and for this reason I usually use it with an external OCXO I put in a small diecast box. This is a newer generation OCXO that has a 4 minute warmup time and you can buy used OCXOs like this on ebay for maybe $15-$25. A typical OCXO like this would deliver about 0.01ppm performance in a typical lab/workroom environment for many months before it aged and required a recal. My little external OCXO usually stays within about 0.03Hz of 10MHz for many months. So that makes it ideal for getting the best from an 8 or 9 digit counter and it warms up to very close to this level of performance in about 4 minutes.