of precise time and frequency measurement
Subject: Re: [time-nuts] Allan Deviation - continuing saga...
I had been using the Shera HC4046 input circuit for my 10811
GPSDO input until I read the test results in the LPRO manual
http://www.symmetricom.com/media/pdf/manuals/man-lpro.pdf
(Table 3-1 on Pg
Dr Bruce Griffiths [EMAIL PROTECTED] wrote:
The 100K+100pF in series with the comparator input must really help in
elevating the noise level.
Jeeze. These AD comparators are used by me in line receivers where
they are usefully terminated at 100 ohms! And here they are putting
100K in front!
Didier Juges said the following on 10/28/2006 12:18 AM:
The clock shaper uses a commercial 10.7 MHz IF transformer, readjusted
down to 10 MHz (see schematic at
http://www.ko4bb.com/ham_radio/Manuals/2_GPS_Stuff/Clock_Shaper.jpg).
It provides light loading to the OCXO through the 390 ohm
John Ackermann N8UR wrote:
To minimize jitter and tempco, you probably ought to stay away from a
comparator if you can. I've had good success using the input circuit
from Brooks Shera's GPSDO which is a 74HC4046 PLL, but using only the
input circuit and not the PLL section itself.
John Ackermann N8UR [EMAIL PROTECTED] wrote:
Didier Juges said the following on 10/28/2006 12:18 AM:
The clock shaper uses a commercial 10.7 MHz IF transformer, readjusted
down to 10 MHz (see schematic at
http://www.ko4bb.com/ham_radio/Manuals/2_GPS_Stuff/Clock_Shaper.jpg).
It provides
Magnus Danielson wrote:
Look at the AD8561 datasheet first. The 74HC4046 is much slower than the
AD8561 and the higher output slewrate of the AD8561 is certainly good to keep
jitter down. The 74HC4046 is worse for that aspect.
What I would rather critize Didiers schematic for is the lack of
From: Didier Juges [EMAIL PROTECTED]
Subject: Re: [time-nuts] Allan Deviation - continuing saga...
Date: Sat, 28 Oct 2006 08:44:27 -0500
Message-ID: [EMAIL PROTECTED]
Magnus Danielson wrote:
Look at the AD8561 datasheet first. The 74HC4046 is much slower than the
AD8561 and the higher output
Didier Juges wrote:
Magnus Danielson wrote:
Look at the AD8561 datasheet first. The 74HC4046 is much slower than the
AD8561 and the higher output slewrate of the AD8561 is certainly good to keep
jitter down. The 74HC4046 is worse for that aspect.
What I would rather critize Didiers
From: Dr Bruce Griffiths [EMAIL PROTECTED]
Subject: Re: [time-nuts] Allan Deviation - continuing saga...
Date: Sun, 29 Oct 2006 10:35:44 +1300
Message-ID: [EMAIL PROTECTED]
Good Morning Bruce!
Comparators are fine with a good layout.
As you sharpen up the rise-times, layout becomes more
