[time-nuts] AD9548 - Clock IC Generates Up to 400 MHz from 1 PPSGPS Signal

Lester Veenstra m0ycm at veenstras.com
Thu Jun 11 01:32:02 EDT 2009

Sync to 1 pps but will not discipline the frequency source

Lester B Veenstra  MØYCM K1YCM
lester at veenstras.com
m0ycm at veenstras.com
k1ycm at veenstras.com
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-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of christopher hoover
Sent: Thursday, June 11, 2009 5:26 AM
To: time-nuts at febo.com
Subject: [time-nuts] AD9548 - Clock IC Generates Up to 400 MHz from 1 PPSGPS

[fyi -- this may be of general interest, but n.b. that this A.D. 
marketing - ch]

Clock IC Generates Up to 400 MHz from 1 PPS GPS Signal

The AD9548 
is the first clock chip in the industry to directly generate up to a 400 
MHz output clock, with extremely low phase noise, that is locked to a 
standard one pulse-per-second (PPS) GPS clock signal. This performance 
is a result of combining Analog Devices' proprietary direct digital 
synthesis (DDS) technology with a state-of-the-art digital phase-locked 
loop (DPLL). Other solutions for synchronizing to the GPS 1 PPS source 
typically rely on one or more frequency upconversion steps. Maintaining 
low output noise, while providing over eight orders of magnitude of 
frequency scaling (1 Hz input to over 100 MHz output), is a significant 
challenge. The AD9548 is able to mitigate this effect thanks to a 
digital loop filter capable of bandwidths as low as 1 MHz (10 Hz to 3 Hz).


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