10 MHz -> 16 MHz clock multiplier
On 02/01/13 19:54, Tom Van Baak wrote:
What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must.
The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions?
One approach is to divide by 5 to get 2 MHz, but recalling that the 20%
PWM factor (top bit of divide by 5 counter) has a strong 8th overtone
compared to the 40% PWM factor, an LC-tank at 16 MHz and a simple
gain-stage (such as the Wenzel sine input) should be able to pull it
off. The divide by 5 is standard TTL/CMOS of your choosing.
Cheers,
Magnus
Tom,
my 50 cents are: Use a 1 Euro expensive ICS503 in a SOIC package to generate
a 160 MHz signal from the 10 MHz without further components needed (except
one c on the VCC and one on the input) and then divide by 10. Expect a 50 ps
one sigma jitter on the output. You MUST use capacitive coupling with an
external oscillator. Easily breadboarded! Have used such a configuration to
generate phase locked clock signals for older FPGAs without internal clock
generation.
Best regards
Ulrich
-----Ursprungliche Nachricht-----
Von: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] Im Auftrag von Tom Van Baak
Gesendet: Mittwoch, 2. Januar 2013 19:55
An: Discussion of precise time and frequency measurement
Betreff: [time-nuts] 10 MHz -> 16 MHz clock multiplier
What's the simplest way to generate 16 MHz from 10 MHz? This
will be for clocking a microcontroller at 16 MHz given 10 MHz
(Cs/Rb/GPSDO). Low price and low parts count is a goal;
jitter is not a concern but absolute long-term phase
coherence is a must.
The ICS525 (as in TAPR Clock-Block) is a good candidate but I
was wondering if there's something cheaper, less functional,
and maybe not SSOP. Any suggestions?
Thanks,
/tvb
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A week ago I asked about a 10 MHz to 16 MHz multiplier. Thanks very much for the suggestions and interesting discussion.
What's the simplest way to generate 16 MHz from 10 MHz? This
will be for clocking a microcontroller at 16 MHz given 10 MHz
(Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter
is not a concern but absolute long-term phase coherence is a must.
The ICS525 (as in TAPR Clock-Block) is a good candidate but I
was wondering if there's something cheaper, less functional, and
maybe not SSOP. Any suggestions?
Thanks,
/tvb
A few of you wanted to know more background. Some portable microcontroller-based timer/counters use a 16 MHz xtal timebase. To transparently give them "atomic" accuracy I thought it would be a cute hack to simply feed them 16 MHz as derived from a good 10 MHz (which we all have). For a quick test I used a house 10 MHz referenced DS345 to produce the 16 MHz square wave. I know some DDS have round-off error but the DS345, at least at this frequency, maintained phase to the nanosecond.
Not wanting to tie up my DS345 indefinitely, I wondered for this fixed 10:16 (5:8) frequency ratio if there was cheap, simple, or clever solution. The TAPR Clock-Block came to mind. The ICS525 chip it uses is cheap (under $5) and trivial to configure so that was clearly one solution. But I was curious what the group would propose.
Anyway, thanks to all who contributed. If there are any stones left unturned, send me email off-line.
/tvb
Don't leave us in suspense :-) What method did you decide to use?
Joe Gray
W5JG
On Mon, Jan 7, 2013 at 8:54 PM, Tom Van Baak tvb@leapsecond.com wrote:
A week ago I asked about a 10 MHz to 16 MHz multiplier. Thanks very much for the suggestions and interesting discussion.
What's the simplest way to generate 16 MHz from 10 MHz? This
will be for clocking a microcontroller at 16 MHz given 10 MHz
(Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter
is not a concern but absolute long-term phase coherence is a must.
The ICS525 (as in TAPR Clock-Block) is a good candidate but I
was wondering if there's something cheaper, less functional, and
maybe not SSOP. Any suggestions?
Thanks,
/tvb
A few of you wanted to know more background. Some portable microcontroller-based timer/counters use a 16 MHz xtal timebase. To transparently give them "atomic" accuracy I thought it would be a cute hack to simply feed them 16 MHz as derived from a good 10 MHz (which we all have). For a quick test I used a house 10 MHz referenced DS345 to produce the 16 MHz square wave. I know some DDS have round-off error but the DS345, at least at this frequency, maintained phase to the nanosecond.
Not wanting to tie up my DS345 indefinitely, I wondered for this fixed 10:16 (5:8) frequency ratio if there was cheap, simple, or clever solution. The TAPR Clock-Block came to mind. The ICS525 chip it uses is cheap (under $5) and trivial to configure so that was clearly one solution. But I was curious what the group would propose.
Anyway, thanks to all who contributed. If there are any stones left unturned, send me email off-line.
/tvb
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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