On Wed, 17 Feb 2016 14:04:31 +0300, Evgeny Filatov
<filatov.ev@mipt.ru> wrote:

>On 13.02.2016 20:29, Eric Jacobsen wrote:
>
>(snip)
>
>>
>> I tried to run this but there is a term,  sgn, near the end that
>> appears to be undefined?     I'm attempting to run it on Octave, so
>> maybe there's a difference there.
>>
>> Cool stuff, though.
>>
>>
>> Eric Jacobsen
>> Anchor Hill Communications
>> http://www.anchorhill.com
>>
>
>I could not reproduce the error in Octave. I used the latest Windows 
>release of Octave and loaded three packages (communications, signal and 
>control). And it worked allright, although more slowly than in Matlab.
>
>Regards,
>Evgeny.

Oh, sorry!   I had fixed it and a few other issues in Octave already.
It was just an issue with passing the arguments.



Eric Jacobsen
Anchor Hill Communications
http://www.anchorhill.com

On 13.02.2016 20:29, Eric Jacobsen wrote:

(snip)

>
> I tried to run this but there is a term,  sgn, near the end that
> appears to be undefined?     I'm attempting to run it on Octave, so
> maybe there's a difference there.
>
> Cool stuff, though.
>
>
> Eric Jacobsen
> Anchor Hill Communications
> http://www.anchorhill.com
>

I could not reproduce the error in Octave. I used the latest Windows 
release of Octave and loaded three packages (communications, signal and 
control). And it worked allright, although more slowly than in Matlab.

Regards,
Evgeny.

On Tue, 16 Feb 2016 22:38:48 +0200, Tauno Voipio wrote:

> On 16.2.16 20:18, Tim Wescott wrote:
>> On Tue, 16 Feb 2016 19:55:17 +0200, Tauno Voipio wrote:
>>
>>> On 16.2.16 18:00, Tim Wescott wrote:
>>>> On Tue, 16 Feb 2016 10:03:49 +0200, Tauno Voipio wrote:
>>>>
>>>>> On 15.2.16 22:54, Steve Pope wrote:
>>>>>> <a.turowski@ymail.com> wrote:
>>>>>>
>>>>>>> I think we all arrived to the conclusion that it all should be
>>>>>>> doable.
>>>>>>> The bigger system is now at the very early stage of feasibility
>>>>>>> study.
>>>>>>> That is why I didn't have a complete set of data regarding
>>>>>>> requirements or signal properties. In couple of weeks I will have
>>>>>>> a meeting with people who designed the sensor. This would be the
>>>>>>> opportunity to ask for more data regarding sensor operation, so if
>>>>>>> you have any questions you want me to ask, shoot away.
>>>>>>
>>>>>> One thing you may need is requirements collapse.  That is, if your
>>>>>> part of the system requires a timebase good to 0.01 ppm, it may be
>>>>>> that other parts of the system require similarly accurate
>>>>>> timebases.
>>>>>> Perhaps there needs to be a system-wide timebase generator,
>>>>>> distinct from your module, since if you "own" the entire timebase
>>>>>> problem, your part of the system might appear disproportionately
>>>>>> expensive.
>>>>>>
>>>>>> Another thing you may want to consider is whether you need live
>>>>>> calibration -- that is, when employing the sensor, you alternate
>>>>>> between a calibration phase (which could be infrequent) and
>>>>>> measurement phase.  This might make life easier.
>>>>>>
>>>>>> Good luck.
>>>>>>
>>>>>> Steve
>>>>>
>>>>>
>>>>> I just wonder what may be a physical system supplying the frequency
>>>>> to be measured to an accuracy in the ppb class, except a frequency
>>>>> standard.
>>>>
>>>> The 10ppb figure does become suspicious, doesn't it?  Some
>>>> measurement system that depends on something like a piezo-electric
>>>> crystal or a mechanical resonator changing it's resonant frequency in
>>>> response to the parameter being measured jumps to mind.
>>>>
>>>> If I'm measuring to "100ppb, 10ppb preferred" then I probably have a
>>>> total error budget of 1ppm or so, and I want the frequency
>>>> measurement part of that error budget to be somewhere between
>>>> definitely small enough and not a worry at all.
>>>>
>>>> I could see such a system being valid if it had temperature
>>>> compensation,
>>>> or if it were measuring temperature.
>>>
>>>
>>> My son, a PhD in measurement technology, likes to say that every
>>> measurement system will be a thermometer, and maybe a barometer,
>>> if sufficiently sensitive.
>>>
>>> I have been suspecting the accuracy spec from the start on.
>>
>> I once sat in a meeting room while a project engineer from a company
>> trying to sell us gyroscopes hold up a soup-can sized gyro and say
>> "This is a gyroscope.  It's also a microphone, accelerometer,
>> thermometer, and various other measuring instruments..."
>>
>> We didn't buy the gyroscope, but it was because it was much too big,
>> not because we didn't like the presentation.
> 
> 
> So, you met a scarcity: a honest salesman. He deserves a prize.

He was the engineering manager.  I suspect that the sales guy was wishing 
for a remote with a "voice off" button.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

On 16.2.16 20:18, Tim Wescott wrote:
> On Tue, 16 Feb 2016 19:55:17 +0200, Tauno Voipio wrote:
>
>> On 16.2.16 18:00, Tim Wescott wrote:
>>> On Tue, 16 Feb 2016 10:03:49 +0200, Tauno Voipio wrote:
>>>
>>>> On 15.2.16 22:54, Steve Pope wrote:
>>>>> <a.turowski@ymail.com> wrote:
>>>>>
>>>>>> I think we all arrived to the conclusion that it all should be
>>>>>> doable.
>>>>>> The bigger system is now at the very early stage of feasibility
>>>>>> study.
>>>>>> That is why I didn't have a complete set of data regarding
>>>>>> requirements or signal properties. In couple of weeks I will have a
>>>>>> meeting with people who designed the sensor. This would be the
>>>>>> opportunity to ask for more data regarding sensor operation, so if
>>>>>> you have any questions you want me to ask, shoot away.
>>>>>
>>>>> One thing you may need is requirements collapse.  That is, if your
>>>>> part of the system requires a timebase good to 0.01 ppm, it may be
>>>>> that other parts of the system require similarly accurate timebases.
>>>>> Perhaps there needs to be a system-wide timebase generator, distinct
>>>>> from your module, since if you "own" the entire timebase problem,
>>>>> your part of the system might appear disproportionately expensive.
>>>>>
>>>>> Another thing you may want to consider is whether you need live
>>>>> calibration -- that is, when employing the sensor, you alternate
>>>>> between a calibration phase (which could be infrequent) and
>>>>> measurement phase.  This might make life easier.
>>>>>
>>>>> Good luck.
>>>>>
>>>>> Steve
>>>>
>>>>
>>>> I just wonder what may be a physical system supplying the frequency to
>>>> be measured to an accuracy in the ppb class, except a frequency
>>>> standard.
>>>
>>> The 10ppb figure does become suspicious, doesn't it?  Some measurement
>>> system that depends on something like a piezo-electric crystal or a
>>> mechanical resonator changing it's resonant frequency in response to
>>> the parameter being measured jumps to mind.
>>>
>>> If I'm measuring to "100ppb, 10ppb preferred" then I probably have a
>>> total error budget of 1ppm or so, and I want the frequency measurement
>>> part of that error budget to be somewhere between definitely small
>>> enough and not a worry at all.
>>>
>>> I could see such a system being valid if it had temperature
>>> compensation,
>>> or if it were measuring temperature.
>>
>>
>> My son, a PhD in measurement technology, likes to say that every
>> measurement system will be a thermometer, and maybe a barometer,
>> if sufficiently sensitive.
>>
>> I have been suspecting the accuracy spec from the start on.
>
> I once sat in a meeting room while a project engineer from a company
> trying to sell us gyroscopes hold up a soup-can sized gyro and say "This
> is a gyroscope.  It's also a microphone, accelerometer, thermometer, and
> various other measuring instruments..."
>
> We didn't buy the gyroscope, but it was because it was much too big, not
> because we didn't like the presentation.


So, you met a scarcity: a honest salesman. He deserves a prize.

-- 

-TV

On Tue, 16 Feb 2016 19:55:17 +0200, Tauno Voipio wrote:

> On 16.2.16 18:00, Tim Wescott wrote:
>> On Tue, 16 Feb 2016 10:03:49 +0200, Tauno Voipio wrote:
>>
>>> On 15.2.16 22:54, Steve Pope wrote:
>>>> <a.turowski@ymail.com> wrote:
>>>>
>>>>> I think we all arrived to the conclusion that it all should be
>>>>> doable.
>>>>> The bigger system is now at the very early stage of feasibility
>>>>> study.
>>>>> That is why I didn't have a complete set of data regarding
>>>>> requirements or signal properties. In couple of weeks I will have a
>>>>> meeting with people who designed the sensor. This would be the
>>>>> opportunity to ask for more data regarding sensor operation, so if
>>>>> you have any questions you want me to ask, shoot away.
>>>>
>>>> One thing you may need is requirements collapse.  That is, if your
>>>> part of the system requires a timebase good to 0.01 ppm, it may be
>>>> that other parts of the system require similarly accurate timebases.
>>>> Perhaps there needs to be a system-wide timebase generator, distinct
>>>> from your module, since if you "own" the entire timebase problem,
>>>> your part of the system might appear disproportionately expensive.
>>>>
>>>> Another thing you may want to consider is whether you need live
>>>> calibration -- that is, when employing the sensor, you alternate
>>>> between a calibration phase (which could be infrequent) and
>>>> measurement phase.  This might make life easier.
>>>>
>>>> Good luck.
>>>>
>>>> Steve
>>>
>>>
>>> I just wonder what may be a physical system supplying the frequency to
>>> be measured to an accuracy in the ppb class, except a frequency
>>> standard.
>>
>> The 10ppb figure does become suspicious, doesn't it?  Some measurement
>> system that depends on something like a piezo-electric crystal or a
>> mechanical resonator changing it's resonant frequency in response to
>> the parameter being measured jumps to mind.
>>
>> If I'm measuring to "100ppb, 10ppb preferred" then I probably have a
>> total error budget of 1ppm or so, and I want the frequency measurement
>> part of that error budget to be somewhere between definitely small
>> enough and not a worry at all.
>>
>> I could see such a system being valid if it had temperature
>> compensation,
>> or if it were measuring temperature.
> 
> 
> My son, a PhD in measurement technology, likes to say that every
> measurement system will be a thermometer, and maybe a barometer,
> if sufficiently sensitive.
> 
> I have been suspecting the accuracy spec from the start on.

I once sat in a meeting room while a project engineer from a company 
trying to sell us gyroscopes hold up a soup-can sized gyro and say "This 
is a gyroscope.  It's also a microphone, accelerometer, thermometer, and 
various other measuring instruments..."

We didn't buy the gyroscope, but it was because it was much too big, not 
because we didn't like the presentation.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

On 16.2.16 18:00, Tim Wescott wrote:
> On Tue, 16 Feb 2016 10:03:49 +0200, Tauno Voipio wrote:
>
>> On 15.2.16 22:54, Steve Pope wrote:
>>> <a.turowski@ymail.com> wrote:
>>>
>>>> I think we all arrived to the conclusion that it all should be doable.
>>>> The bigger system is now at the very early stage of feasibility study.
>>>> That is why I didn't have a complete set of data regarding
>>>> requirements or signal properties. In couple of weeks I will have a
>>>> meeting with people who designed the sensor. This would be the
>>>> opportunity to ask for more data regarding sensor operation, so if you
>>>> have any questions you want me to ask, shoot away.
>>>
>>> One thing you may need is requirements collapse.  That is, if your part
>>> of the system requires a timebase good to 0.01 ppm, it may be that
>>> other parts of the system require similarly accurate timebases.
>>> Perhaps there needs to be a system-wide timebase generator, distinct
>>> from your module, since if you "own" the entire timebase problem, your
>>> part of the system might appear disproportionately expensive.
>>>
>>> Another thing you may want to consider is whether you need live
>>> calibration -- that is, when employing the sensor, you alternate
>>> between a calibration phase (which could be infrequent) and measurement
>>> phase.  This might make life easier.
>>>
>>> Good luck.
>>>
>>> Steve
>>
>>
>> I just wonder what may be a physical system supplying the frequency to
>> be measured to an accuracy in the ppb class, except a frequency
>> standard.
>
> The 10ppb figure does become suspicious, doesn't it?  Some measurement
> system that depends on something like a piezo-electric crystal or a
> mechanical resonator changing it's resonant frequency in response to the
> parameter being measured jumps to mind.
>
> If I'm measuring to "100ppb, 10ppb preferred" then I probably have a
> total error budget of 1ppm or so, and I want the frequency measurement
> part of that error budget to be somewhere between definitely small enough
> and not a worry at all.
>
> I could see such a system being valid if it had temperature compensation,
> or if it were measuring temperature.


My son, a PhD in measurement technology, likes to say that every
measurement system will be a thermometer, and maybe a barometer,
if sufficiently sensitive.

I have been suspecting the accuracy spec from the start on.

-- 

-TV

On Tue, 16 Feb 2016 10:03:49 +0200, Tauno Voipio wrote:

> On 15.2.16 22:54, Steve Pope wrote:
>> <a.turowski@ymail.com> wrote:
>>
>>> I think we all arrived to the conclusion that it all should be doable.
>>> The bigger system is now at the very early stage of feasibility study.
>>> That is why I didn't have a complete set of data regarding
>>> requirements or signal properties. In couple of weeks I will have a
>>> meeting with people who designed the sensor. This would be the
>>> opportunity to ask for more data regarding sensor operation, so if you
>>> have any questions you want me to ask, shoot away.
>>
>> One thing you may need is requirements collapse.  That is, if your part
>> of the system requires a timebase good to 0.01 ppm, it may be that
>> other parts of the system require similarly accurate timebases. 
>> Perhaps there needs to be a system-wide timebase generator, distinct
>> from your module, since if you "own" the entire timebase problem, your
>> part of the system might appear disproportionately expensive.
>>
>> Another thing you may want to consider is whether you need live
>> calibration -- that is, when employing the sensor, you alternate
>> between a calibration phase (which could be infrequent) and measurement
>> phase.  This might make life easier.
>>
>> Good luck.
>>
>> Steve
> 
> 
> I just wonder what may be a physical system supplying the frequency to
> be measured to an accuracy in the ppb class, except a frequency
> standard.

The 10ppb figure does become suspicious, doesn't it?  Some measurement 
system that depends on something like a piezo-electric crystal or a 
mechanical resonator changing it's resonant frequency in response to the 
parameter being measured jumps to mind.

If I'm measuring to "100ppb, 10ppb preferred" then I probably have a 
total error budget of 1ppm or so, and I want the frequency measurement 
part of that error budget to be somewhere between definitely small enough 
and not a worry at all.

I could see such a system being valid if it had temperature compensation, 
or if it were measuring temperature.

-- 
www.wescottdesign.com

On 15.2.16 22:54, Steve Pope wrote:
> <a.turowski@ymail.com> wrote:
>
>> I think we all arrived to the conclusion that it all should be doable.
>> The bigger system is now at the very early stage of feasibility study.
>> That is why I didn't have a complete set of data regarding requirements
>> or signal properties. In couple of weeks I will have a meeting with
>> people who designed the sensor. This would be the opportunity to ask for
>> more data regarding sensor operation, so if you have any questions you
>> want me to ask, shoot away.
>
> One thing you may need is requirements collapse.  That is, if your part
> of the system requires a timebase good to 0.01 ppm, it may be that other
> parts of the system require similarly accurate timebases.  Perhaps
> there needs to be a system-wide timebase generator, distinct from your
> module, since if you "own" the entire timebase problem, your part of
> the system might appear disproportionately expensive.
>
> Another thing you may want to consider is whether you need live
> calibration -- that is, when employing the sensor, you alternate
> between a calibration phase (which could be infrequent) and
> measurement phase.  This might make life easier.
>
> Good luck.
>
> Steve


I just wonder what may be a physical system supplying the frequency
to be measured to an accuracy in the ppb class, except a frequency
standard.

-- 

-TV

<a.turowski@ymail.com> wrote:

>I think we all arrived to the conclusion that it all should be doable.
>The bigger system is now at the very early stage of feasibility study.
>That is why I didn't have a complete set of data regarding requirements
>or signal properties. In couple of weeks I will have a meeting with
>people who designed the sensor. This would be the opportunity to ask for
>more data regarding sensor operation, so if you have any questions you
>want me to ask, shoot away. 

One thing you may need is requirements collapse.  That is, if your part 
of the system requires a timebase good to 0.01 ppm, it may be that other
parts of the system require similarly accurate timebases.  Perhaps
there needs to be a system-wide timebase generator, distinct from your
module, since if you "own" the entire timebase problem, your part of 
the system might appear disproportionately expensive.

Another thing you may want to consider is whether you need live
calibration -- that is, when employing the sensor, you alternate
between a calibration phase (which could be infrequent) and
measurement phase.  This might make life easier.

Good luck.

Steve

W dniu niedziela, 14 lutego 2016 06:16:51 UTC użytkownik rickman napisał:
> On 2/12/2016 9:13 PM, Cedron wrote:
> > [...snip...]
> >
> >> Ah.  That's what you meant.  Yes, a rapidly varying frequency would screw
> >
> >> things up, particularly if the amplitude varies with frequency >--
> >
> > [...snip...]
> >
> >> www.wescottdesign.com
> >
> > The OP stated that the frequency doesn't vary that rapidly and the
> > amplitude stays constant.
> >
> > I come at this from a mathematical perspective, not a practical one,
> > meaning I don't have that deep of an understanding of how ADC circuits
> > really function in these situations.  I have my doubts that any ADC
> > circuit sampling at 5 kHz is going to accurately capture signal values
> > from a ~150 kHz tone.
> 
> There are ADC designs that are suitable for undersampling a 150 kHz 
> signal and there are some that are not so suitable.  Generally such a 
> design would use a track and hold so the ADC doesn't see a changing 
> input during the aperture window.
> 
> 
> > Since the OP only needs readings every second, I wonder why the signal
> > frequency needs to be so high.  It sounds like a system that is using a
> > VCO (voltage controlled oscillator) to measure some physical property.  It
> > would seem that he would be better off, if possible, to redesign the
> > hardware with a much lower frequency, and sample at a higher frequency.
> > If the frequency were brought down to around 10 kHz, a standard 44.1 kHz
> > sound card would be more than adequate for the job.  The precision would
> > probably improve too.
> 
> There seem to be lots of tradeoffs and 100 ppb is an ambitious goal.
> 
> -- 
> 
> Rick

Hi all,

I was really busy for couple of days and couldn't check my emails. Sorry about that. In general the problem I've described in OP is just one of the problems that need to be solved in lot bigger system. I've shared the details of this problem with the group because:

1) it is an interesting problem and I know that the forum likes that kind of puzzles
2) I needed to get a second opinion about do ability of that kind of thing and what details are missing

I think we all arrived to the conclusion that it all should be doable. The bigger system is now at the very early stage of feasibility study. That is why I didn't have a complete set of data regarding requirements or signal properties. In couple of weeks I will have a meeting with people who designed the sensor. This would be the opportunity to ask for more data regarding sensor operation, so if you have any questions you want me to ask, shoot away. I will try do my best to extract the information out of them and share that with the group if possible.

Best regard,
Adam