Recently I have been comparing the phase noise of the HOlzworth HX4210 and the
LTC7957-4.
I have found that the performance of these devices is comparable with a 10MHz
sinewave input with a PN noise floor below -160dBc/Hz.
For offsets below 100Hz the LTC6957-4 is quieter and for offsets below 50Hz
You alternate LTC7957-4 and LTC6957-4 and it is only the later that exists.
The LTC6957-4 has a single-stage amplifier stage input, with somewhat
programmable bandwidth. I assume you used the 50 MHz BW setting.
Cheers,
Magnus
On 07/29/2014 10:55 AM, br...@ko4bb.com wrote:
Recently I have
Sorry, I meant the LTC6957-4 of course._SELA = l
FILTA = L
FILTB = H
ie an input stage BW of 160MHz as recommended for a 10MHz + 10dBm input.
Input for the HX4210 was +14dBm.
Comparator was that used in David Partridge's programmable divider (includes the
74AC04 buffers).
Bruce
On July 29,
Sent: 29 July 2014 12:00
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Sine to square wave converter Phase Noise
Sorry, I meant the LTC6957-4 of course._SELA = l FILTA = L FILTB = H ie an
input stage BW of 160MHz as recommended for a 10MHz + 10dBm input.
Input
-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of br...@ko4bb.com
Sent: 29 July 2014 12:00
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Sine to square wave converter Phase Noise
Sorry, I meant the LTC6957-4 of course._SELA = l
Am 29.07.2014 um 13:38 schrieb David C. Partridge:
Further to my previous post:
I note that the LTC6957 is 3.3V CMOS rather than 5V. Do you have a
recommmendation for a level converter to 5V logic? Would a 74AC04 using a
5V supply cope well enough in that role or is there a better solution?
However that will increase the signal transition times to significanly greater
than the 300ps seen at the LTC6957 output.
Bruce
On July 29, 2014 at 7:54 AM Gerhard Hoffmann dk...@arcor.de wrote:
Am 29.07.2014 um 13:38 schrieb David C. Partridge:
Further to my previous post:
I note that
-boun...@febo.com] On
Behalf Of br...@ko4bb.com
Sent: 29 July 2014 12:00
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Sine to square wave converter Phase Noise
Sorry, I meant the LTC6957-4 of course._SELA = l FILTA = L FILTB = H ie an
input stage BW
Am 29.07.2014 um 14:47 schrieb br...@ko4bb.com:
However that will increase the signal transition times to significanly
greater than the 300ps seen at the LTC6957 output.
I had standard sot23/sc70 Fairchild single cmos gates with rise/fall
times faster than 500ps.
Gerhard
12:00
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Sine to square wave converter Phase Noise
Sorry, I meant the LTC6957-4 of course._SELA = l FILTA = L FILTB = H ie an
input stage BW of 160MHz as recommended for a 10MHz + 10dBm input.
Input for the HX4210
Hej Bruce,
Many thanks for the clarification!
This could be an alternate input stage to the TADD-2 too.
Cheers,
Magnus
On 07/29/2014 12:59 PM, br...@ko4bb.com wrote:
Sorry, I meant the LTC6957-4 of course._SELA = l
FILTA = L
FILTB = H
ie an input stage BW of 160MHz as recommended for a 10MHz
Hi,
What comparator did you use in your evaluation? An 74AC04, 74AC14 or other
LT, AD, etc?
Regards,
Vasco Soares
- Original Message -
From: br...@ko4bb.com
To: time-nuts@febo.com
Sent: Tuesday, July 29, 2014 9:55 AM
Subject: [time-nuts] Sine to square wave converter Phase Noise
?
Regards,
David Partridge
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of br...@ko4bb.com
Sent: 29 July 2014 12:00
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Sine to square wave converter Phase Noise
The Achilles heel of that biasing technique is that the emitter currents of the
pair of pnp's is affected by the noise on the 20V supply.
The 20V supply noise is only attenuated by a factor of 5 or so when both
transistors have equal collector currents.
I have both an LTC evaluation board for the
Bruce,
please make those tests it will help me to how to proceed and probably many
other time nuts.
Bert Kehren
In a message dated 7/11/2014 3:50:36 A.M. Eastern Daylight Time,
br...@ko4bb.com writes:
The Achilles heel of that biasing technique is that the emitter currents
of the
pair
Bruce wrote:
The Achilles heel of that biasing technique is that the emitter
currents of the
pair of pnp's is affected by the noise on the 20V supply.
Yes, you do need a quiet supply -- I suppose I should have mentioned
that. But sufficiently quiet supplies are not hard to design,
they're
As part of the FE 405 B project a separate output circuit is in the works.
The universal controller and auxiliary board are the same as used in the
FE5680A GPSDO but because of the very low ADEV a separate circuit board that
divides by three and has also two ground isolated transformer
On July 10, 2014 at 10:55 AM ewkeh...@aol.com wrote:
As part of the FE 405 B project a separate output circuit is in the works.
The universal controller and auxiliary board are the same as used in the
FE5680A GPSDO but because of the very low ADEV a separate circuit board that
divides by
look Charles Wenzel's waveform conversion:
http://www.wenzel.com/documents/waveform.html
73
Alex
On 7/10/2014 11:40 AM, br...@ko4bb.com wrote:
On July 10, 2014 at 10:55 AM ewkeh...@aol.com wrote:
As part of the FE 405 B project a separate output circuit is in the works.
The universal
Bert,
On 07/10/2014 04:55 PM, ewkeh...@aol.com wrote:
As part of the FE 405 B project a separate output circuit is in the works.
The universal controller and auxiliary board are the same as used in the
FE5680A GPSDO but because of the very low ADEV a separate circuit board that
divides by
Thank you Alex I have that info I am concerned about rise time
Bert Kehren
Sent from Samsung tabletAlexander Pummer alex...@ieee.org wrote:
look Charles Wenzel's waveform conversion:
http://www.wenzel.com/documents/waveform.html
73
Alex
On 7/10/2014 11:40 AM, br...@ko4bb.com wrote:
On July
Magnus
Thank you for your recommendation I use Wenzel extensively as a matter of
fact I just completed in the last three days two boards that have Wenzel on
it and in my projects I can count 14 boards. Rise and fall time is my
concern but I am open to suggestions that is why I turned to the
Bert,
OK, good that you are familiar with it, it was not obvious in that message.
If you consider it as the first stage, and that you then can put another
(faster) stage after it until you go for comparator. It's just the same
thing as the multistage for beat-note, but you run at a higher
Will the added stage negatively effect ADEV?
Bert
In a message dated 7/10/2014 3:48:44 P.M. Eastern Daylight Time,
mag...@rubidium.dyndns.org writes:
Bert,
OK, good that you are familiar with it, it was not obvious in that message.
If you consider it as the first stage, and that you
How much of an improvement does the LTC6957 give over, say, a simple
74AC gate?
Actually, is there a list of different techniques and the performance of
each? I know that the LPRO Integration manual gives some good info for
phase noise, but I'm not aware of a similar document for slew rate
Bert,
Hard to predict without looking at the details. The main battle for a
sine-to-square is to fight white and flicker phase noise as well as
additive repetitive signals such as 50 Hz power noise creeping into the
jitter. At the same time we try to get the conversion more long-term
stable,
The schematic of the converter I attached to my previous message did
not make it through in my copy of the message, so it may be missing
from other people's copies, as well. If anyone wants it and did not
receive it, it is available at:
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