BC
Bob Camp
Sat, Nov 3, 2012 11:06 PM
Hi
The relay can be replaced. Not so much with the input amp. If it goes, you lost the counter. The displays also die from time to time. Like the relay, they can be replaced.
Bob
On Nov 3, 2012, at 6:14 PM, Magnus Danielson magnus@rubidium.dyndns.org wrote:
On 11/03/2012 09:36 PM, Bob Camp wrote:
Hi
In the case of the 53132, the power supply seems to be the weak link. Out of maybe a hundred or so in the fleet, we see maybe one or two die each month. On the SR620 the power supply also seems to go from time to time. Both have the normal keyboard and display issues, but those can be fixed. If you go back to things like the 5335, the weak point is the input amp, it blows if you get +5 on it. Like power transformers - not a replaceable item...
Another weak point on the 5335 is the relay. We had to replace it and the relay-holder, but once that was done, it was back up operational.
The 5335 ticks in as the most human-friendly of the counters at work, while the 53132 is competing with the 5372 as being the most human-unfriendly, where the 5372 has more capabilities to present, so it gets used more.
Cheers,
Magnus
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Hi
The relay *can* be replaced. Not so much with the input amp. If it goes, you lost the counter. The displays also die from time to time. Like the relay, they can be replaced.
Bob
On Nov 3, 2012, at 6:14 PM, Magnus Danielson <magnus@rubidium.dyndns.org> wrote:
> On 11/03/2012 09:36 PM, Bob Camp wrote:
>> Hi
>>
>> In the case of the 53132, the power supply seems to be the weak link. Out of maybe a hundred or so in the fleet, we see maybe one or two die each month. On the SR620 the power supply also seems to go from time to time. Both have the normal keyboard and display issues, but those can be fixed. If you go back to things like the 5335, the weak point is the input amp, it blows if you get +5 on it. Like power transformers - not a replaceable item...
>
> Another weak point on the 5335 is the relay. We had to replace it and the relay-holder, but once that was done, it was back up operational.
> The 5335 ticks in as the most human-friendly of the counters at work, while the 53132 is competing with the 5372 as being the most human-unfriendly, where the 5372 has more capabilities to present, so it gets used more.
>
> Cheers,
> Magnus
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
CP
Charles P. Steinmetz
Sat, Nov 3, 2012 11:39 PM
Given that slew rate is so critical, why do we distribute sine waves
and perform the zero-crossing detection at every target instrument?
Magnus made some good points in response to your question. To
elaborate a bit: it is much easier to provide a friendly transmission
environment for a sine wave (single frequency), and sine waves are
less sensitive to imperfections in the transmission environment
(impedance discontinuities and mismatches, noise ingress,
etc.). Reflections in the transmission environment will put funny
steps in what started life as clean square waves or pulses, and
differential phase shifts will also mis-shape square waves or
pulses. This can even be a problem with sine waves -- see, for
example, the NIST paper on the timing effects of distortion in sine
wave sources for an example of the sensitivity of sine wave systems
to harmonics (Walls and Ascarrunz, The Effect of Harmonic Distortion
on Phase Errors in Frequency Distribution and Synthesis) -- but it is
much worse with square waves or pulses.
Sine wave systems are also much less prone to radiating
noise. Anyone who operates one or more frequency standards as well
as sensitive RF receivers can testify that sine waves are much less
of a hassle.
Best regards,
Charles
david wrote:
>Given that slew rate is so critical, why do we distribute sine waves
>and perform the zero-crossing detection at every target instrument?
Magnus made some good points in response to your question. To
elaborate a bit: it is much easier to provide a friendly transmission
environment for a sine wave (single frequency), and sine waves are
less sensitive to imperfections in the transmission environment
(impedance discontinuities and mismatches, noise ingress,
etc.). Reflections in the transmission environment will put funny
steps in what started life as clean square waves or pulses, and
differential phase shifts will also mis-shape square waves or
pulses. This can even be a problem with sine waves -- see, for
example, the NIST paper on the timing effects of distortion in sine
wave sources for an example of the sensitivity of sine wave systems
to harmonics (Walls and Ascarrunz, The Effect of Harmonic Distortion
on Phase Errors in Frequency Distribution and Synthesis) -- but it is
much worse with square waves or pulses.
Sine wave systems are also much less prone to radiating
noise. Anyone who operates one or more frequency standards as well
as sensitive RF receivers can testify that sine waves are much less
of a hassle.
Best regards,
Charles
CA
Chris Albertson
Sun, Nov 4, 2012 12:05 AM
The below is correct but a simpler way to say it is this:
"A square wave contains the fundamental frequency plus every odd harmonic
up to infinity. A sine wave contains only the fundamental frequency."
It is the "up to infinity" part that causes all the trouble. And yes it
really does go to infinity, at least in theory. but in real life you can't
have frequencies so high so without them you can't and don't have a perfect
square wave. In other words perfect square wave can't esist in the real
world but perfect sine wave, at least in theory could
On Sat, Nov 3, 2012 at 4:39 PM, Charles P. Steinmetz <
charles_steinmetz@lavabit.com> wrote:
david wrote:
Given that slew rate is so critical, why do we distribute sine waves and
perform the zero-crossing detection at every target instrument?
Magnus made some good points in response to your question. To elaborate a
bit: it is much easier to provide a friendly transmission environment for a
sine wave (single frequency), and sine waves are less sensitive to
imperfections in the transmission environment (impedance discontinuities
and mismatches, noise ingress, etc.). Reflections in the transmission
environment will put funny steps in what started life as clean square waves
or pulses, and differential phase shifts will also mis-shape square waves
or pulses. This can even be a problem with sine waves -- see, for example,
the NIST paper on the timing effects of distortion in sine wave sources for
an example of the sensitivity of sine wave systems to harmonics (Walls and
Ascarrunz, The Effect of Harmonic Distortion on Phase Errors in Frequency
Distribution and Synthesis) -- but it is much worse with square waves or
pulses.
Sine wave systems are also much less prone to radiating noise. Anyone who
operates one or more frequency standards as well as sensitive RF receivers
can testify that sine waves are much less of a hassle.
Best regards,
Charles
_____________**
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/**
mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
--
Chris Albertson
Redondo Beach, California
The below is correct but a simpler way to say it is this:
"A square wave contains the fundamental frequency plus every odd harmonic
up to infinity. A sine wave contains only the fundamental frequency."
It is the "up to infinity" part that causes all the trouble. And yes it
really does go to infinity, at least in theory. but in real life you can't
have frequencies so high so without them you can't and don't have a perfect
square wave. In other words perfect square wave can't esist in the real
world but perfect sine wave, at least in theory could
On Sat, Nov 3, 2012 at 4:39 PM, Charles P. Steinmetz <
charles_steinmetz@lavabit.com> wrote:
> david wrote:
>
> Given that slew rate is so critical, why do we distribute sine waves and
>> perform the zero-crossing detection at every target instrument?
>>
>
> Magnus made some good points in response to your question. To elaborate a
> bit: it is much easier to provide a friendly transmission environment for a
> sine wave (single frequency), and sine waves are less sensitive to
> imperfections in the transmission environment (impedance discontinuities
> and mismatches, noise ingress, etc.). Reflections in the transmission
> environment will put funny steps in what started life as clean square waves
> or pulses, and differential phase shifts will also mis-shape square waves
> or pulses. This can even be a problem with sine waves -- see, for example,
> the NIST paper on the timing effects of distortion in sine wave sources for
> an example of the sensitivity of sine wave systems to harmonics (Walls and
> Ascarrunz, The Effect of Harmonic Distortion on Phase Errors in Frequency
> Distribution and Synthesis) -- but it is much worse with square waves or
> pulses.
>
> Sine wave systems are also much less prone to radiating noise. Anyone who
> operates one or more frequency standards as well as sensitive RF receivers
> can testify that sine waves are much less of a hassle.
>
> Best regards,
>
> Charles
>
>
>
>
>
> ______________________________**_________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/**
> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts>
> and follow the instructions there.
>
--
Chris Albertson
Redondo Beach, California
PG
Peter Gottlieb
Sun, Nov 4, 2012 12:13 AM
Of course you can't have a perfect square wave! That would imply zero
transition time and since frequency is inverse to time that implies infinitely
high frequency bandwidth is required to achieve that perfect square wave.
Getting a "square" wave with a "fast enough" slew rate between high and low
levels is certainly achievable and better than that perfect square wave. Be
careful what you ask for, because with a perfect square wave you would have such
high frequency content that you would get induced noise everywhere.
Peter
On 11/3/2012 8:05 PM, Chris Albertson wrote:
The below is correct but a simpler way to say it is this:
"A square wave contains the fundamental frequency plus every odd harmonic
up to infinity. A sine wave contains only the fundamental frequency."
It is the "up to infinity" part that causes all the trouble. And yes it
really does go to infinity, at least in theory. but in real life you can't
have frequencies so high so without them you can't and don't have a perfect
square wave. In other words perfect square wave can't esist in the real
world but perfect sine wave, at least in theory could
On Sat, Nov 3, 2012 at 4:39 PM, Charles P. Steinmetz <
charles_steinmetz@lavabit.com> wrote:
david wrote:
Given that slew rate is so critical, why do we distribute sine waves and
perform the zero-crossing detection at every target instrument?
Magnus made some good points in response to your question. To elaborate a
bit: it is much easier to provide a friendly transmission environment for a
sine wave (single frequency), and sine waves are less sensitive to
imperfections in the transmission environment (impedance discontinuities
and mismatches, noise ingress, etc.). Reflections in the transmission
environment will put funny steps in what started life as clean square waves
or pulses, and differential phase shifts will also mis-shape square waves
or pulses. This can even be a problem with sine waves -- see, for example,
the NIST paper on the timing effects of distortion in sine wave sources for
an example of the sensitivity of sine wave systems to harmonics (Walls and
Ascarrunz, The Effect of Harmonic Distortion on Phase Errors in Frequency
Distribution and Synthesis) -- but it is much worse with square waves or
pulses.
Sine wave systems are also much less prone to radiating noise. Anyone who
operates one or more frequency standards as well as sensitive RF receivers
can testify that sine waves are much less of a hassle.
Best regards,
Charles
_____________**
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/**
mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Of course you can't have a perfect square wave! That would imply zero
transition time and since frequency is inverse to time that implies infinitely
high frequency bandwidth is required to achieve that perfect square wave.
Getting a "square" wave with a "fast enough" slew rate between high and low
levels is certainly achievable and better than that perfect square wave. Be
careful what you ask for, because with a perfect square wave you would have such
high frequency content that you would get induced noise everywhere.
Peter
On 11/3/2012 8:05 PM, Chris Albertson wrote:
> The below is correct but a simpler way to say it is this:
>
> "A square wave contains the fundamental frequency plus every odd harmonic
> up to infinity. A sine wave contains only the fundamental frequency."
>
> It is the "up to infinity" part that causes all the trouble. And yes it
> really does go to infinity, at least in theory. but in real life you can't
> have frequencies so high so without them you can't and don't have a perfect
> square wave. In other words perfect square wave can't esist in the real
> world but perfect sine wave, at least in theory could
>
>
> On Sat, Nov 3, 2012 at 4:39 PM, Charles P. Steinmetz <
> charles_steinmetz@lavabit.com> wrote:
>
>> david wrote:
>>
>> Given that slew rate is so critical, why do we distribute sine waves and
>>> perform the zero-crossing detection at every target instrument?
>>>
>> Magnus made some good points in response to your question. To elaborate a
>> bit: it is much easier to provide a friendly transmission environment for a
>> sine wave (single frequency), and sine waves are less sensitive to
>> imperfections in the transmission environment (impedance discontinuities
>> and mismatches, noise ingress, etc.). Reflections in the transmission
>> environment will put funny steps in what started life as clean square waves
>> or pulses, and differential phase shifts will also mis-shape square waves
>> or pulses. This can even be a problem with sine waves -- see, for example,
>> the NIST paper on the timing effects of distortion in sine wave sources for
>> an example of the sensitivity of sine wave systems to harmonics (Walls and
>> Ascarrunz, The Effect of Harmonic Distortion on Phase Errors in Frequency
>> Distribution and Synthesis) -- but it is much worse with square waves or
>> pulses.
>>
>> Sine wave systems are also much less prone to radiating noise. Anyone who
>> operates one or more frequency standards as well as sensitive RF receivers
>> can testify that sine waves are much less of a hassle.
>>
>> Best regards,
>>
>> Charles
>>
>>
>>
>>
>>
>> ______________________________**_________________
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/**
>> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts>
>> and follow the instructions there.
>>
>
>
MD
Magnus Danielson
Sun, Nov 4, 2012 12:46 AM
On 11/04/2012 01:13 AM, Peter Gottlieb wrote:
Of course you can't have a perfect square wave! That would imply zero
transition time
... oh, THAT would be useful! :D No trigger point jitter!
... and it would be a hell to contain within the cables and connectors
we have, as they leak a lot as you get up into frequency.
and since frequency is inverse to time that implies
infinitely high frequency bandwidth is required to achieve that perfect
square wave. Getting a "square" wave with a "fast enough" slew rate
between high and low levels is certainly achievable and better than that
perfect square wave. Be careful what you ask for, because with a perfect
square wave you would have such high frequency content that you would
get induced noise everywhere.
Indeed. Bob has shown this.
Another aspect of it is that phase-shifts at higher frequencies may eat
into the phase shift of the zero transition, so it may for some systems
give a worse environmental/temperature dependence than a sine would.
Then again, if you check your signal properly, a square-wave may be
exactly what you want and need. It's just that again, your milage may vary.
Cheers,
Magnus
On 11/04/2012 01:13 AM, Peter Gottlieb wrote:
> Of course you can't have a perfect square wave! That would imply zero
> transition time
... oh, THAT would be useful! :D No trigger point jitter!
... and it would be a hell to contain within the cables and connectors
we have, as they leak a lot as you get up into frequency.
> and since frequency is inverse to time that implies
> infinitely high frequency bandwidth is required to achieve that perfect
> square wave. Getting a "square" wave with a "fast enough" slew rate
> between high and low levels is certainly achievable and better than that
> perfect square wave. Be careful what you ask for, because with a perfect
> square wave you would have such high frequency content that you would
> get induced noise everywhere.
Indeed. Bob has shown this.
Another aspect of it is that phase-shifts at higher frequencies may eat
into the phase shift of the zero transition, so it may for some systems
give a worse environmental/temperature dependence than a sine would.
Then again, if you check your signal properly, a square-wave may be
exactly what you want and need. It's just that again, your milage may vary.
Cheers,
Magnus
BC
Bob Camp
Sun, Nov 4, 2012 12:21 PM
Hi
If you slew rate limit the square wave (which is reality) you get a sin(x)/x frequency response. It doesn't go to infinity, but the lobes keep going for quite a while.
Things like cables and connectors have upper frequency limits as well. A square wave will only be happy with a linear phase shift. Both cables and connectors depart from a linear phase vs frequency response if you go high enough in frequency. Some get quite nasty. The original Heliax with the constant spacing in the inner supports was really crazy when hit with a fast pulse. It pretty much rang forever and ever…
A simple square wave implies a DC level for a switch point. With long runs that gets messy. Most practical systems go differential. You double the cable cost, but get back to a simple switch point.
No free lunch.
Bob
On Nov 3, 2012, at 8:46 PM, Magnus Danielson magnus@rubidium.dyndns.org wrote:
On 11/04/2012 01:13 AM, Peter Gottlieb wrote:
Of course you can't have a perfect square wave! That would imply zero
transition time
... oh, THAT would be useful! :D No trigger point jitter!
... and it would be a hell to contain within the cables and connectors we have, as they leak a lot as you get up into frequency.
and since frequency is inverse to time that implies
infinitely high frequency bandwidth is required to achieve that perfect
square wave. Getting a "square" wave with a "fast enough" slew rate
between high and low levels is certainly achievable and better than that
perfect square wave. Be careful what you ask for, because with a perfect
square wave you would have such high frequency content that you would
get induced noise everywhere.
Indeed. Bob has shown this.
Another aspect of it is that phase-shifts at higher frequencies may eat into the phase shift of the zero transition, so it may for some systems give a worse environmental/temperature dependence than a sine would.
Then again, if you check your signal properly, a square-wave may be exactly what you want and need. It's just that again, your milage may vary.
Cheers,
Magnus
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Hi
If you slew rate limit the square wave (which is reality) you get a sin(x)/x frequency response. It doesn't go to infinity, but the lobes keep going for quite a while.
Things like cables and connectors have upper frequency limits as well. A square wave will only be happy with a linear phase shift. Both cables and connectors depart from a linear phase vs frequency response if you go high enough in frequency. Some get quite nasty. The original Heliax with the constant spacing in the inner supports was really crazy when hit with a fast pulse. It pretty much rang forever and ever…
A simple square wave implies a DC level for a switch point. With long runs that gets messy. Most practical systems go differential. You double the cable cost, but get back to a simple switch point.
No free lunch.
Bob
On Nov 3, 2012, at 8:46 PM, Magnus Danielson <magnus@rubidium.dyndns.org> wrote:
> On 11/04/2012 01:13 AM, Peter Gottlieb wrote:
>> Of course you can't have a perfect square wave! That would imply zero
>> transition time
>
> ... oh, THAT would be useful! :D No trigger point jitter!
>
> ... and it would be a hell to contain within the cables and connectors we have, as they leak a lot as you get up into frequency.
>
>> and since frequency is inverse to time that implies
>> infinitely high frequency bandwidth is required to achieve that perfect
>> square wave. Getting a "square" wave with a "fast enough" slew rate
>> between high and low levels is certainly achievable and better than that
>> perfect square wave. Be careful what you ask for, because with a perfect
>> square wave you would have such high frequency content that you would
>> get induced noise everywhere.
>
> Indeed. Bob has shown this.
>
> Another aspect of it is that phase-shifts at higher frequencies may eat into the phase shift of the zero transition, so it may for some systems give a worse environmental/temperature dependence than a sine would.
>
> Then again, if you check your signal properly, a square-wave may be exactly what you want and need. It's just that again, your milage may vary.
>
> Cheers,
> Magnus
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
