[time-nuts] Fwd: 10MHz to 80MHz frequency multiplier suggestions
Tijd Dingen
tijddingen at yahoo.com
Fri Feb 4 18:17:00 UTC 2011
Hello Said,
That CVHD-950-100 looks to be just the ticket. Nice price/performance. Thank you
for the recommendation! :)
I also noticed their CVS575-500. Nice, bit pricier though...
regards,
Fred
----- Original Message ----
From: "SAIDJACK at aol.com" <SAIDJACK at aol.com>
To: time-nuts at febo.com
Sent: Thu, February 3, 2011 6:06:16 AM
Subject: Re: [time-nuts] Fwd: 10MHz to 80MHz frequency multiplier suggestions
Hi Fred,
I like the Crystek CVHD parts, and MtronPTI also has a number of good ones.
bye,
Said
In a message dated 2/2/2011 19:50:10 Pacific Standard Time,
tijddingen at yahoo.com writes:
Hello Said,
> Low Noise 100MHz VCXO's are readily available at mouser and digikey (so
> are 80MHz units), and programming the ADF4002 is straight forward with
the
> help from the AD online tools. It can be bit-banged with any
microcontroller.
Any particular ones that are in stock at digikey/mouser that you would
recommend?
regards,
Fred
----- Original Message ----
From: "SAIDJACK at aol.com" <SAIDJACK at aol.com>
To: time-nuts at febo.com
Sent: Wed, February 2, 2011 9:12:38 PM
Subject: [time-nuts] Fwd: 10MHz to 80MHz frequency multiplier suggestions
Hello Raj,
our ULN-1100 and ULN-2550 GPSDO's use a 100MHz VCXO locked to the 10MHz
OCXO via an ADF4002 PLL with less than 40Hz bandwidth. After careful
optimization of the layout and the loop filter, the phase noise results
are
quite
excellent at 100MHz, see the attached plot. The plot shows two versions of
the PLL loop filter from the design phase of the products, one has been
more
optimized. You can see that the noise floor is almost -170dBc/Hz at
100MHz.
You get the best of two worlds: the absolute frequency accuracy of the
GPSDO, and the very low phase noise of the VCXO above the PLL bandwidth.
It is
clearly visible that the VCXO phase noise inside the loop bandwidth is
actually also reduced by locking it to the 10MHz OCXO (the PN curve below
the
loop bandwidth frequency of ~30Hz would just continue going up without
the
PLL)
Low Noise 100MHz VCXO's are readily available at mouser and digikey (so
are 80MHz units), and programming the ADF4002 is straight forward with
the
help from the AD online tools. It can be bit-banged with any
microcontroller.
bye,
Said
From: Raj <_vu2zap at gmail.com_ (mailto:vu2zap at gmail.com) >
Date: January 31, 2011 21:11:46 HST
To: Discussion of precise time and frequency measurement
<_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >
Subject: Re: [time-nuts] 10MHz to 80MHz frequency multiplier suggestions
Reply-To: Discussion of precise time and frequency measurement
<_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >
I was contemplating the same thing. I fed the output to a bifilar
transformer and
diode doubler and got good results. I have to add an amp and double it
again twice
more. It is still on breadboard. The object was to multiply the error 8x
and compare.
Probably a PLL locking to 80 Mhz will retain the long term accuracy of
the
TBolt reference.
Raj, vu2zap
At 31-01-2011, you wrote:
I'd like to convert the 10MHz output of a Thunderbolt to 80MHz: it should
be
used as a 3.3V clock for an A/D converter.
Even if I have already taken a look to documentation from KO4BB and Wenzel
regarding frequency multiplier,
I'm asking if you have some more references or even better, some
schematics
of a working 8x multiplier.
. thanks in advance
_ Elio Corbolante.
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