The HP sceme in the patent refers to an array of series and parallel
diodes to reduce noise.
Just paralleling them does not reduce the noise!
Might this not depend what the type of noise was ?? JRC use this technique
in the RF stage of their receivers but I am wondering if this is only valid
@febo.com
Sent: Tue, December 18, 2012 1:32:11 PM
Subject: [time-nuts] Noisy varactor diodes
I was recently repairing a noisy A3 module for an HP 5065A.
...
Anybody know where to get an MV840 ???
Thanks,
Corby
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The HP sceme in the patent refers to an array of series and parallel
diodes to reduce noise.
Just paralleling them does not reduce the noise!
The 4 paralleled in the 5065 are to give enough phase deviation for the
low modulation level applied. (150mv)
The symptom was a fluctuating 2nd
-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: [time-nuts] noisy varactor diodes
The HP sceme in the patent refers to an array of series and parallel
diodes to reduce noise.
Just paralleling them does not reduce the noise!
The 4 paralleled in the 5065
The HP sceme in the patent refers to an array of series and parallel
diodes to reduce noise.
Just paralleling them does not reduce the noise!
Still, the patent claims seem pretty obvious. Paralleling n diodes would
reduce their noise contribution by the usual 3 dB * log2(n) factor, but
time and frequency measurement'time-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] noisy varactor diodes
The HP sceme in the patent refers to an array of series and parallel
diodes to reduce noise.
Just
Try these guys aiHave had luck on other parts. Aint cheap
http://www.americanmicrosemi.com/information/spec/?ss_pn=MV840
Regards
Paul
WB8TSL
On Tue, Dec 18, 2012 at 1:29 PM, cdel...@juno.com wrote:
I was recently repairing a noisy A3 module for an HP 5065A.
The phase modulator has 4 varactor
What are the horizontal and vertical settings for that picture?
Ed
On 12/18/2012 12:29 PM, cdel...@juno.com wrote:
I was recently repairing a noisy A3 module for an HP 5065A.
The phase modulator has 4 varactor diodes in parallel.
Since I suspected a diode, I removed them one at a time.
Of
will say impressive let us no what american micro semi wants for a diode.
I suspect a few of us may need them at some point
On Tue, Dec 18, 2012 at 2:31 PM, cdel...@juno.com wrote:
The vertical is 50Mv/cm and the horizontal is 1ms/cm
The diode is connected to + 20VDC and then to a 20K
Subject: [time-nuts] Noisy varactor diodes
I was recently repairing a noisy A3 module for an HP 5065A.
...
Anybody know where to get an MV840 ???
Thanks,
Corby
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Good find on the diodes and as you say at least worth the try. Will bet
they are 10 x less expensive then americanmicrosemi. But I will say in a
pinch they bailed me out. :-) Tunnel diode for a TDR.
Regards
Paul.
On Tue, Dec 18, 2012 at 2:55 PM, Brooke Clarke bro...@pacific.net wrote:
Hi Corby:
John 2 with the same type of issue that is bad luck or simply age. Oh my do
I for see this in my future?
I would be willing to bet it exactly looks like your description. I like
the fact that for $1.23 you can get something from digikey. I do tend to
trust them and mouser.
Regards
Paul.
On Tue,
On Tue, 18 Dec 2012 16:51:02 -0500, paul swed paulsw...@gmail.com
wrote:
John 2 with the same type of issue that is bad luck or simply age. Oh my do
I for see this in my future?
I would be willing to bet it exactly looks like your description. I like
the fact that for $1.23 you can get something
I have tried to work with 4 Star Electronics. They only want to deal
with large quantity orders. I would be interested to hear if anyone
has had better luck.
David N1HAC
On 12/18/12 4:42 PM, John Miles wrote:
[1]www.octopart.com identifies 23 of them in stock at a reseller
Am 18.12.2012 22:42, schrieb John Miles:
Just curious, what was the 5065A acting like with the bad diode? Mine seems
to run quietly for days at a time, but then occasionally it generates excess
low-level random noise for a period of hours to days (see image). Every
time I've tried to get
HP has a patent on this scheme. The paralleling of the diodes is for
noise reduction. Personally, I would have rejected the patent since this
is the kind of thing that is obvious to those skilled in the art.
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