DMTD - analog multiplier vs. diode mixer ?
My little HP5065 project is continually running into the jitter of
my HP5370B counter which is annoying me, so I'm looking int DMTD.
Everybody seems to be using traditional diode-mixers for DMTD,
and to be honest I fail to see the attraction.
Why wouldn't a analog multiplier like AD835 be better idea ?
What am I overlooking ?
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
The noise of such Gilbert cell based analog multipliers far exceeds that of the traditional mixer.
Bruce
On Wednesday, 6 January 2016 9:01 AM, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote:
My little HP5065 project is continually running into the jitter of
my HP5370B counter which is annoying me, so I'm looking int DMTD.
Everybody seems to be using traditional diode-mixers for DMTD,
and to be honest I fail to see the attraction.
Why wouldn't a analog multiplier like AD835 be better idea ?
What am I overlooking ?
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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Poul-Henning,
I have some guesses but I look forward to others.
I think the analog multipliers are complicated in pins and support
circuitry especially if single power supply.
I used lower frequency Analog Devices units in early experimentation on the
wwvb d-psk-r.
Granted they worked. They were also pricey. But thats relative.
They can deliver gain as compared to a mixer and thats a plus.
Regards
Paul
WB8TSL
On Tue, Jan 5, 2016 at 2:56 PM, Poul-Henning Kamp phk@phk.freebsd.dk
wrote:
My little HP5065 project is continually running into the jitter of
my HP5370B counter which is annoying me, so I'm looking int DMTD.
Everybody seems to be using traditional diode-mixers for DMTD,
and to be honest I fail to see the attraction.
Why wouldn't a analog multiplier like AD835 be better idea ?
What am I overlooking ?
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
You could also consider a DDMTD as useed in CERN's White rabbit project.Apart from the sine to logic level conversion its all digital. With care in the design the jitter should be sub picosecond.
Bruce
On Wednesday, 6 January 2016 9:01 AM, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote:
My little HP5065 project is continually running into the jitter of
my HP5370B counter which is annoying me, so I'm looking int DMTD.
Everybody seems to be using traditional diode-mixers for DMTD,
and to be honest I fail to see the attraction.
Why wouldn't a analog multiplier like AD835 be better idea ?
What am I overlooking ?
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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 Bruce,
Thanks a LOT for your response to Poul's query! I've been searching for DMTD info for a few some time now, and I haven't come up with a lot. Searching for "CERN White Rabbit" got me more in a few minutes than I've found in months. Like Poul, I've become interested in building a DMTD to overcome the limitations of my 5370A, but I haven't had time to actually do anything about it yet.
Bob
From: Bruce Griffiths <bruce.griffiths@xtra.co.nz>
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Tuesday, January 5, 2016 2:19 PM
Subject: Re: [time-nuts] DMTD - analog multiplier vs. diode mixer ?
You could also consider a DDMTD as useed in CERN's White rabbit project.Apart from the sine to logic level conversion its all digital. With care in the design the jitter should be sub picosecond.
Bruce
On Wednesday, 6 January 2016 9:01 AM, Poul-Henning Kamp phk@phk.freebsd.dk wrote:
My little HP5065 project is continually running into the jitter of
my HP5370B counter which is annoying me, so I'm looking int DMTD.
Everybody seems to be using traditional diode-mixers for DMTD,
and to be honest I fail to see the attraction.
Why wouldn't a analog multiplier like AD835 be better idea ?
What am I overlooking ?
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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.
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
In message 553575724.582265.1452024437677.JavaMail.yahoo@mail.yahoo.com, Bruce Griffiths writes:
The noise of such Gilbert cell based analog multipliers far exceeds that of the traditional mixer.
Yes, but does that really matter in this case ?
The interesting output will be coming out of a LPF so
most of the noise will die there?
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
In message CAD2JfAhperEkfSTG5c2U8waGkv0kY3mcbdz8w1+4J+OOaaLb2w@mail.gmail.com, paul swed writes:
I think the analog multipliers are complicated in pins and support
circuitry especially if single power supply.
The AD835 is 8-pins and as easy as they come I think.
Not needing isolation amps seems like a plus to me.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
With some sine-to-square conversion as signal conditioning, not too hard
these days, this could be a relatively straight forward approach.
CERN already have digital clocks, so the DDMTD approach fits them well.
For normal mixers you want to signal condition the signal prior to the
mixers, and then signal-condition the beat notes too.
For DDMTD you do the same, but you do the post mister conditioning in
the digital domain.
I have always assumed that signal-to-noise have been the main difference
between the Gilbert cell multiplies vs. diode mixers.
Cheer1s,
Magnus
On 01/05/2016 09:19 PM, Bruce Griffiths wrote:
You could also consider a DDMTD as useed in CERN's White rabbit project.Apart from the sine to logic level conversion its all digital. With care in the design the jitter should be sub picosecond.
Bruce
On Wednesday, 6 January 2016 9:01 AM, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote:
My little HP5065 project is continually running into the jitter of
my HP5370B counter which is annoying me, so I'm looking int DMTD.
Everybody seems to be using traditional diode-mixers for DMTD,
and to be honest I fail to see the attraction.
Why wouldn't a analog multiplier like AD835 be better idea ?
What am I overlooking ?
Mini-circuits has packaged phase detectors plug-in, surface, and with
connectors for $20 TO $70. Diode bridges with transformers. They also have
cheap wideband amps. Bet a simple DDMTD could be built with these? I know...I
wish I did have the time at present.
Happy New Year!
Don
Magnus Danielson
With some sine-to-square conversion as signal conditioning, not too hard
these days, this could be a relatively straight forward approach.
CERN already have digital clocks, so the DDMTD approach fits them well.
For normal mixers you want to signal condition the signal prior to the
mixers, and then signal-condition the beat notes too.
For DDMTD you do the same, but you do the post mister conditioning in
the digital domain.
I have always assumed that signal-to-noise have been the main difference
between the Gilbert cell multiplies vs. diode mixers.
Cheer1s,
Magnus
On 01/05/2016 09:19 PM, Bruce Griffiths wrote:
You could also consider a DDMTD as useed in CERN's White rabbit
project.Apart from the sine to logic level conversion its all digital. With
care in the design the jitter should be sub picosecond.
Bruce
On Wednesday, 6 January 2016 9:01 AM, Poul-Henning Kamp
phk@phk.freebsd.dk wrote:
My little HP5065 project is continually running into the jitter of
my HP5370B counter which is annoying me, so I'm looking int DMTD.
Everybody seems to be using traditional diode-mixers for DMTD,
and to be honest I fail to see the attraction.
Why wouldn't a analog multiplier like AD835 be better idea ?
What am I overlooking ?
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Six Mile Systems LLC, 17850 Six Mile Road
Huson, MT, 59846
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CEL 406-241-5093
Skype: buffler2
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www.sixmilesystems.com
On Tuesday, January 05, 2016 09:37:00 PM Poul-Henning Kamp wrote:
Bruce Griffiths writes:
The noise of such Gilbert cell based analog multipliers far exceeds that of
the traditional mixer.
Yes, but does that really matter in this case ?
The interesting output will be coming out of a LPF so
most of the noise will die there?/
Yes I believe it does as the mixer multiplier noise sets a lower limit to the
beat frequency jitter.
If only the noise from the 2 mixers were correlated then the jitter
contribution from this would largely cancel out as does the noisee
contribution of the offset oscillator.
Bruce