[time-nuts] time-nuts Digest, Vol 146, Issue 35
Alexander Pummer
alexpcs at ieee.org
Sun Sep 18 15:20:13 EDT 2016
Sometimes rectifiers generating very high harmonics particularly if the
rectifier is used close to it's current limits. The reverse recovery
time increases, therefore the current is conducted after the polarity
change for a very short time --until the now majority charge carriers
sweeping out from the junction -- the turn off is very fast [ that
effect is used by the step-recovery frequency multipliers] an the result
is very high multiplied harmonics with substantial amplitude since that
very narrow current pulse is produced by a crowbar across the first
charge capacitor's voltage. If there is some wire, which have the proper
length for on "output resonator " the high frequency source is perfect
and the repetition frequency - which is the double line frequency could
be heard with the spectrum analyzer's AM The demodulator. The amplitude
of the high frequency pulses is much higher as it displayed on the
spectrum analyzer, but the spectrum analyzer will integrate --due to
it's limited bandwidth -- and shows the average of the pulses. Why is
that important? because these high level pulses could modify an
amplifier biasing, and perhaps cause periodically repeating jitters or
even kill the input of an amplifier. I run into that problem some forty
years ego with output rectifiers of switching mode power supplies. If
you look old circuit diagrams of power supplies you could find some
small capacitors connected across the rectifiers, these capacitors
taking care the "buzz" in the old radios.
73
KJ6UHN
Alex
On 9/18/2016 7:39 AM, hardy wrote:
> Hello
> I see that you are using E4406A for direct phasenoise measurement--your results are the same as with my E4406A and thunderbolt-but have no spurs.
> I think it must be your powersupply for your thunderbolt that made those spurs.
> Hardy
>
> -----Oprindelig meddelelse-----
> Fra: time-nuts [mailto:time-nuts-bounces at febo.com] På vegne af time-nuts-request at febo.com
> Sendt: 18. september 2016 15:29
> Til: time-nuts at febo.com
> Emne: time-nuts Digest, Vol 146, Issue 35
>
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> Today's Topics:
>
> 1. Re: Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from
> signal. (Lars Walenius)
> 2. Re: Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from
> signal. (Bruce Griffiths)
> 3. Re: Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from
> signal. (Peter Marczinowski)
> 4. Re: Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from
> signal. (Peter Marczinowski)
> 5. Re: Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from
> signal. (Dan Rae)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 18 Sep 2016 12:52:21 +0000
> From: Lars Walenius <lars.walenius at hotmail.com>
> To: 'Discussion of precise time and frequency measurement'
> <time-nuts at febo.com>
> Subject: Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz
> and 200Hz from signal.
> Message-ID:
> <VI1PR0701MB19182CC04AF1A9AB2A74B8FBF3F50 at VI1PR0701MB1918.eurprd07.prod.outlook.com>
>
> Content-Type: text/plain; charset="iso-8859-1"
>
> What is the specification for the Spectrum analyzer? They don´t tend to be useful for OCXO measurments so is this especially good? Or is it only the Analyzer phase noise we see?
>
>
>
> Lars
>
>
>
> Från: David C. Partridge<mailto:david.partridge at perdrix.co.uk>
> Skickat: den 18 september 2016 14:43
> Till: 'Bruce Griffiths'<mailto:bruce.griffiths at xtra.co.nz>; 'Discussion of precise time and frequency measurement'<mailto:time-nuts at febo.com>
> Ämne: Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from signal.
>
>
>
> I've just redone the measurement without the external attenuator and with 10dB attenuation set internally to the analyser.
>
> The results are attached.
>
> Dave
>
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Bruce Griffiths
> Sent: 18 September 2016 12:52
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from signal.
>
> The signal level is also very low.
> Brue
>
> On Sunday, 18 September 2016 11:47 PM, Magnus Danielson <magnus at rubidium.dyndns.org> wrote:
>
>
> The phase-noise still looks fairly high. How do you measure this?
>
> Cheers,
> Magnus
>
> On 09/18/2016 01:27 PM, David C. Partridge wrote:
>> Now that's interesting I just re-ran the measurement, and got a quite different result which is attached. The spurs have GONE.
>>
>> My only guess right now is that the E4406A power supply is getting quieter as it has been on for longer (I've only had it powered for short periods before now).
>>
>> Dave
>>
>> -----Original Message-----
>> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of
>> Magnus Danielson
>> Sent: 18 September 2016 11:56
>> To: time-nuts at febo.com
>> Cc: magnus at rubidium.se
>> Subject: Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from signal.
>>
>> Hi,
>>
>> On 09/18/2016 12:26 PM, David C. Partridge wrote:
>>> The local power is 50Hz, so I can understand the 100Hz spurs, but I
>>> don't quite "get" where the 200Hz spurs are coming from. Or is that
>>> just BAU harmonics?
>> Consider full-wave rectification of 50 Hz, the power consumption load
>> on the capacitor after the rectifier creates an inverse sawtooth wave
>> of
>> 100 Hz, and sawtooth waveshape have both even and odd harmonics.
>>
>> While much of this is regulated out in the next step, some of it makes it though.
>>
>> Cheers,
>> Magnus
>>
>>>
>>> Thanks
>>>
>>> Dave
>>>
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
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> ------------------------------
>
> Message: 2
> Date: Sun, 18 Sep 2016 12:55:49 +0000 (UTC)
> From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
> To: "David C. Partridge" <david.partridge at perdrix.co.uk>, 'Discussion
> of precise time and frequency measurement' <time-nuts at febo.com>
> Subject: Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz
> and 200Hz from signal.
> Message-ID: <1026001816.394838.1474203349917 at mail.yahoo.com>
> Content-Type: text/plain; charset=UTF-8
>
> Still way above what it should be.Whats the noise floor of the measurement system?
> Bruce
>
> On Monday, 19 September 2016 12:43 AM, David C. Partridge <david.partridge at perdrix.co.uk> wrote:
>
>
> I've just redone the measurement without the external attenuator and with 10dB attenuation set internally to the analyser.
>
> The results are attached.
>
> Dave
>
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Bruce Griffiths
> Sent: 18 September 2016 12:52
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from signal.
>
> The signal level is also very low.
> Brue
>
> On Sunday, 18 September 2016 11:47 PM, Magnus Danielson <magnus at rubidium.dyndns.org> wrote:
>
>
> The phase-noise still looks fairly high. How do you measure this?
>
> Cheers,
> Magnus
>
> On 09/18/2016 01:27 PM, David C. Partridge wrote:
>> Now that's interesting I just re-ran the measurement, and got a quite different result which is attached. The spurs have GONE.
>>
>> My only guess right now is that the E4406A power supply is getting quieter as it has been on for longer (I've only had it powered for short periods before now).
>>
>> Dave
>>
>> -----Original Message-----
>> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of
>> Magnus Danielson
>> Sent: 18 September 2016 11:56
>> To: time-nuts at febo.com
>> Cc: magnus at rubidium.se
>> Subject: Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and 200Hz from signal.
>>
>> Hi,
>>
>> On 09/18/2016 12:26 PM, David C. Partridge wrote:
>>> The local power is 50Hz, so I can understand the 100Hz spurs, but I
>>> don't quite "get" where the 200Hz spurs are coming from. Or is that
>>> just BAU harmonics?
>> Consider full-wave rectification of 50 Hz, the power consumption load
>> on the capacitor after the rectifier creates an inverse sawtooth wave
>> of
>> 100 Hz, and sawtooth waveshape have both even and odd harmonics.
>>
>> While much of this is regulated out in the next step, some of it makes it though.
>>
>> Cheers,
>> Magnus
>>
>>>
>>> Thanks
>>>
>>> Dave
>>>
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
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>> and follow the instructions there.
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>>
>>
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>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
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> _______________________________________________
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>
> ------------------------------
>
> Message: 3
> Date: Sun, 18 Sep 2016 13:11:55 +0200
> From: Peter Marczinowski <peter.laboe at gmail.com>
> To: Discussion of precise time and frequency measurement
> <time-nuts at febo.com>
> Cc: "magnus at rubidium.se" <magnus at rubidium.se>
> Subject: Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz
> and 200Hz from signal.
> Message-ID:
> <CAFLUov06di5Pb_J7-BWcYj=HmL-bWLeFNWy2g1h+x0yNsRNtwQ at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Even harmonics are caused by asymmetrical nonlinearities, odd harmonics by
> symmetrical nonlinearities.
>
> Peter
>
>
> Am Sonntag, 18. September 2016 schrieb Magnus Danielson :
>
>> Hi,
>>
>> On 09/18/2016 12:26 PM, David C. Partridge wrote:
>>
>>> The local power is 50Hz, so I can understand the 100Hz spurs, but I don't
>>> quite "get" where the 200Hz spurs are coming from. Or is that just BAU
>>> harmonics?
>>>
>> Consider full-wave rectification of 50 Hz, the power consumption load on
>> the capacitor after the rectifier creates an inverse sawtooth wave of 100
>> Hz, and sawtooth waveshape have both even and odd harmonics.
>>
>> While much of this is regulated out in the next step, some of it makes it
>> though.
>>
>> Cheers,
>> Magnus
>>
>>
>>> Thanks
>>>
>>> Dave
>>>
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/m
>>> ailman/listinfo/time-nuts
>>> and follow the instructions there.
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>
> ------------------------------
>
> Message: 4
> Date: Sun, 18 Sep 2016 13:24:42 +0200
> From: Peter Marczinowski <peter.laboe at gmail.com>
> To: Discussion of precise time and frequency measurement
> <time-nuts at febo.com>
> Subject: Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz
> and 200Hz from signal.
> Message-ID:
> <CAFLUov2UvDK2AbnyJ4+9c6vGaN3nDRzeLp6-Ray=458XKO_-CQ at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Assuming a nonlinearity, a distortion or partly clipping of only one
> halfwave, would result in a massive even harmonic, as the 200Hz in the
> example. From this point of view "as expected", but a different distortion
> could as well result in any other even harmonic.
>
> Peter
>
>
> Am Sonntag, 18. September 2016 schrieb David C. Partridge :
>
>> Thanks, that makes sense. Is the PN plot much as expected, or is it
>> "could do better"?
>>
>> Thanks again
>> Dave
>> -----Original Message-----
>> From: time-nuts [mailto:time-nuts-bounces at febo.com <javascript:;>] On
>> Behalf Of Magnus Danielson
>> Sent: 18 September 2016 11:56
>> To: time-nuts at febo.com <javascript:;>
>> Cc: magnus at rubidium.se <javascript:;>
>> Subject: Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz and
>> 200Hz from signal.
>>
>> Hi,
>>
>> On 09/18/2016 12:26 PM, David C. Partridge wrote:
>>> The local power is 50Hz, so I can understand the 100Hz spurs, but I
>>> don't quite "get" where the 200Hz spurs are coming from. Or is that
>>> just BAU harmonics?
>> Consider full-wave rectification of 50 Hz, the power consumption load on
>> the capacitor after the rectifier creates an inverse sawtooth wave of
>> 100 Hz, and sawtooth waveshape have both even and odd harmonics.
>>
>> While much of this is regulated out in the next step, some of it makes it
>> though.
>>
>> Cheers,
>> Magnus
>>
>>>
>>> Thanks
>>>
>>> Dave
>>>
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com <javascript:;> To
>> unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com <javascript:;> To
>> unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
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>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com <javascript:;>
>> To unsubscribe, go to https://www.febo.com/cgi-bin/
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>
> ------------------------------
>
> Message: 5
> Date: Sun, 18 Sep 2016 06:23:32 -0700
> From: Dan Rae <danrae at verizon.net>
> To: Discussion of precise time and frequency measurement
> <time-nuts at febo.com>
> Subject: Re: [time-nuts] Thunderbolt spurs on 10MHz output at 100Hz
> and 200Hz from signal.
> Message-ID: <35c6e8aa-c4fc-70c0-7111-152f8c03d86a at verizon.net>
> Content-Type: text/plain; charset="utf-8"; Format="flowed"
>
> On 9/18/2016 5:42 AM, David C. Partridge wrote:
>> I've just redone the measurement without the external attenuator and with 10dB attenuation set internally to the analyser.
>>
>> The results are attached.
>>
> I suspect that you are measuring the analyser phase noise, but it's
> rather early in the morning...
>
> I attach, if I can get it to work, a plot of three different Tbolts on
> my 3048A system.
>
> Dan
> -------------- next part --------------
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> ------------------------------
>
> End of time-nuts Digest, Vol 146, Issue 35
> ******************************************
>
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