10 MHz -> 16 MHz clock multiplier
One way is to divide by 10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output thru a
narrow 16 MHz filter and amplify. Sounds difficult but the filter can be one
or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160. The output of the divide by 10 needs to
be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
Ideally the pulse width should be a half period of 16 MHz for the maximum
harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a NAND
gate.
One input of the gate is directly connected and the other is delayed. You can
use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav
At 07:41 PM 1/2/2013 +0000, you 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?
Thanks,
/tvb
Where can one get some of these mythical 74HC90 's and 74AC90 's that
have been mentioned.
None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
Also data-sheets are not to be found.
Thanks
On 4/01/2013 5:13 AM, Bill Fuqua wrote:
One way is to divide by 10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output thru a
narrow 16 MHz filter and amplify. Sounds difficult but the filter can
be one
or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160. The output of the divide by 10
needs to
be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
Ideally the pulse width should be a half period of 16 MHz for the
maximum harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a
NAND gate.
One input of the gate is directly connected and the other is delayed.
You can
use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav
At 07:41 PM 1/2/2013 +0000, you 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?
Thanks,
/tvb
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Am 04.01.2013 01:59, schrieb Max:
Where can one get some of these mythical 74HC90 's and 74AC90 's that
have been mentioned.
None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
Also data-sheets are not to be found.
you can't find 'em because they're not there (Lou Reed, "Busload Of
Faith")
regards, Gerhard
They do not exist as I found out (again) not long ago. The last 7490
made was LS (low power schottky) and I use quite a few of them.
Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
apparently either never went into production or very few were
produced.
The closest non-TTL alternative that I found was the 74HC390 or
74HCT390 which is basically two 7490 counters in one package.
On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3yba@gmail.com wrote:
Where can one get some of these mythical 74HC90 's and 74AC90 's that
have been mentioned.
None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
Also data-sheets are not to be found.
Thanks
On 4/01/2013 5:13 AM, Bill Fuqua wrote:
One way is to divide by 10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output thru a
narrow 16 MHz filter and amplify. Sounds difficult but the filter can
be one
or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160. The output of the divide by 10
needs to
be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
Ideally the pulse width should be a half period of 16 MHz for the
maximum harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a
NAND gate.
One input of the gate is directly connected and the other is delayed.
You can
use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav
At 07:41 PM 1/2/2013 +0000, you 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?
Thanks,
/tvb
time-nuts mailing list -- time-nuts@febo.com
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Isn't there a fast divide by N counter that you could set to 10? Maybe even
in ECL?
----- Original Message -----
From: "David" davidwhess@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Thursday, January 03, 2013 8:49 PM
Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier
They do not exist as I found out (again) not long ago. The last 7490
made was LS (low power schottky) and I use quite a few of them.
Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
apparently either never went into production or very few were
produced.
The closest non-TTL alternative that I found was the 74HC390 or
74HCT390 which is basically two 7490 counters in one package.
On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3yba@gmail.com wrote:
Where can one get some of these mythical 74HC90 's and 74AC90 's that
have been mentioned.
None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
Also data-sheets are not to be found.
Thanks
On 4/01/2013 5:13 AM, Bill Fuqua wrote:
One way is to divide by 10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output thru a
narrow 16 MHz filter and amplify. Sounds difficult but the filter can
be one
or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160. The output of the divide by 10
needs to
be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
Ideally the pulse width should be a half period of 16 MHz for the
maximum harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a
NAND gate.
One input of the gate is directly connected and the other is delayed.
You can
use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav
At 07:41 PM 1/2/2013 +0000, you 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?
Thanks,
/tvb
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
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To unsubscribe, go to
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Ahhh, the beauty of the 74xx90 is that you can have a symetrical output
by using the divide by two after the divide by five.
Max
On 4/01/2013 1:02 PM, Tom Miller wrote:
Isn't there a fast divide by N counter that you could set to 10? Maybe
even in ECL?
----- Original Message ----- From: "David" davidwhess@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Thursday, January 03, 2013 8:49 PM
Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier
They do not exist as I found out (again) not long ago. The last 7490
made was LS (low power schottky) and I use quite a few of them.
Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
apparently either never went into production or very few were
produced.
The closest non-TTL alternative that I found was the 74HC390 or
74HCT390 which is basically two 7490 counters in one package.
On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3yba@gmail.com wrote:
Where can one get some of these mythical 74HC90 's and 74AC90 's that
have been mentioned.
None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
Also data-sheets are not to be found.
Thanks
On 4/01/2013 5:13 AM, Bill Fuqua wrote:
One way is to divide by 10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output
thru a
narrow 16 MHz filter and amplify. Sounds difficult but the filter can
be one
or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160. The output of the divide by 10
needs to
be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
Ideally the pulse width should be a half period of 16 MHz for the
maximum harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a
NAND gate.
One input of the gate is directly connected and the other is delayed.
You can
use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav
At 07:41 PM 1/2/2013 +0000, you 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?
Thanks,
/tvb
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
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To unsubscribe, go to
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and follow the instructions there.
Oh, there are lots, well, at least some presetable synchronous
counters in fast logic families that could be used but that would
require extra glue logic. Alternatively if you just want to divide by
5 or some other small fixed number, you can use a couple of flip-flips
and gates.
On Thu, 03 Jan 2013 21:02:32 -0500, "Tom Miller"
tmiller@skylinenet.net wrote:
Isn't there a fast divide by N counter that you could set to 10? Maybe even
in ECL?
----- Original Message -----
From: "David" davidwhess@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Thursday, January 03, 2013 8:49 PM
Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier
They do not exist as I found out (again) not long ago. The last 7490
made was LS (low power schottky) and I use quite a few of them.
Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
apparently either never went into production or very few were
produced.
The closest non-TTL alternative that I found was the 74HC390 or
74HCT390 which is basically two 7490 counters in one package.
On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3yba@gmail.com wrote:
Where can one get some of these mythical 74HC90 's and 74AC90 's that
have been mentioned.
None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
Also data-sheets are not to be found.
Thanks
On 4/01/2013 5:13 AM, Bill Fuqua wrote:
One way is to divide by 10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output thru a
narrow 16 MHz filter and amplify. Sounds difficult but the filter can
be one
or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160. The output of the divide by 10
needs to
be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
Ideally the pulse width should be a half period of 16 MHz for the
maximum harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a
NAND gate.
One input of the gate is directly connected and the other is delayed.
You can
use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav
At 07:41 PM 1/2/2013 +0000, you 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?
Thanks,
/tvb
On 1/3/2013 6:22 PM, David wrote:
Alternatively if you just want to divide by
5 or some other small fixed number, you can use a couple of flip-flips
and gates.
Flip-flips are good for digitally implementing tick-tick clocks, right?
:-) (Use flop-flops for tock-tock.)
THis is exactly what they are talking about the 74HC390 can do over
50MHz and costs abut 30 cents. You don't need ECL or anything so
exotic the 30 cent part will work. Set it for divide by 5. I guess
this is imperfect enough that there is some fourth harmonic content in
the 2MHz square wave, then you select that with a narrow band filter
and amplify it to whatever you need. A smart design might try and
add fourth harmonics be using a slightly not-symetric 2MHz square wave
My question is about the phase noise of the final 16MHz signal. Do
crystal filters "clean up" the signal. It seems that after several
16MHz crystals in series the output should look a lot like an XO.
On Thu, Jan 3, 2013 at 6:02 PM, Tom Miller tmiller@skylinenet.net wrote:
Isn't there a fast divide by N counter that you could set to 10? Maybe even
in ECL?
----- Original Message ----- From: "David" davidwhess@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Thursday, January 03, 2013 8:49 PM
Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier
They do not exist as I found out (again) not long ago. The last 7490
made was LS (low power schottky) and I use quite a few of them.
Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
apparently either never went into production or very few were
produced.
The closest non-TTL alternative that I found was the 74HC390 or
74HCT390 which is basically two 7490 counters in one package.
On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3yba@gmail.com wrote:
Where can one get some of these mythical 74HC90 's and 74AC90 's that
have been mentioned.
None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
Also data-sheets are not to be found.
Thanks
On 4/01/2013 5:13 AM, Bill Fuqua wrote:
One way is to divide by 10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output thru a
narrow 16 MHz filter and amplify. Sounds difficult but the filter can
be one
or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160. The output of the divide by 10
needs to
be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
Ideally the pulse width should be a half period of 16 MHz for the
maximum harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a
NAND gate.
One input of the gate is directly connected and the other is delayed.
You can
use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav
At 07:41 PM 1/2/2013 +0000, you 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?
Thanks,
/tvb
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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To unsubscribe, go to
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--
Chris Albertson
Redondo Beach, California
Paul Wade built a board recently to do just this. www.w1ghz.org.
Bob
On Fri, Jan 4, 2013 at 12:16 PM, Chris Albertson
albertson.chris@gmail.comwrote:
THis is exactly what they are talking about the 74HC390 can do over
50MHz and costs abut 30 cents. You don't need ECL or anything so
exotic the 30 cent part will work. Set it for divide by 5. I guess
this is imperfect enough that there is some fourth harmonic content in
the 2MHz square wave, then you select that with a narrow band filter
and amplify it to whatever you need. A smart design might try and
add fourth harmonics be using a slightly not-symetric 2MHz square wave
My question is about the phase noise of the final 16MHz signal. Do
crystal filters "clean up" the signal. It seems that after several
16MHz crystals in series the output should look a lot like an XO.
On Thu, Jan 3, 2013 at 6:02 PM, Tom Miller tmiller@skylinenet.net wrote:
Isn't there a fast divide by N counter that you could set to 10? Maybe
even
in ECL?
----- Original Message ----- From: "David" davidwhess@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Thursday, January 03, 2013 8:49 PM
Subject: Re: [time-nuts] 10 MHz -> 16 MHz clock multiplier
They do not exist as I found out (again) not long ago. The last 7490
made was LS (low power schottky) and I use quite a few of them.
Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they
apparently either never went into production or very few were
produced.
The closest non-TTL alternative that I found was the 74HC390 or
74HCT390 which is basically two 7490 counters in one package.
On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3yba@gmail.com wrote:
Where can one get some of these mythical 74HC90 's and 74AC90 's that
have been mentioned.
None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
Also data-sheets are not to be found.
Thanks
On 4/01/2013 5:13 AM, Bill Fuqua wrote:
One way is to divide by 10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output thru
a
narrow 16 MHz filter and amplify. Sounds difficult but the filter can
be one
or two 16 MHz crystals followed by a simple amplifier. Look at the
reference input circuit for a PTS-160. The output of the divide by 10
needs to
be asymmetrical so it produces even harmonics. If you are using a
divide divide by 5&2 such as a 74HC90, divide by 2 first then by 5.
Ideally the pulse width should be a half period of 16 MHz for the
maximum harmonic content at 16 MHz.
You can take the output of the frequency divider and send it to a
NAND gate.
One input of the gate is directly connected and the other is delayed.
You can
use an RC with a variable capacitor to ground to get it just right.
Just adjust the capacitor to get the maximum output from your
filter amplifier.
73
Bill wa4lav
At 07:41 PM 1/2/2013 +0000, you 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?
Thanks,
/tvb
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
--
Chris Albertson
Redondo Beach, California
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