Readily available 10MHz divide by 96 10MHz down counter
 

Hi

for my quite unstable counters I've got some 0.1ppm 9.6MHz VCXO's
(guaranteed over temperature range -20...+20°C), the problem is that
the original XO is 1MHz with 7490 divider, and now I need a divide by
96 downcounter. The VCXO drives a 74LS14, so it shouldn't be any fan
out problem, but I am not aware what is the readily available divider
to choose. The counter is mentioned on
http://home.online.no/~la8ak/m21.htm , but it is Norwegian text

hpe 2 hr fm u

73
Jan-Martin, LA8AK
http://home.online.no/~la8ak/d.htm
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J M Noeding wrote:

Hi

for my quite unstable counters I've got some 0.1ppm 9.6MHz VCXO's
(guaranteed over temperature range -20...+20°C), the problem is that
the original XO is 1MHz with 7490 divider, and now I need a divide by
96 downcounter. The VCXO drives a 74LS14, so it shouldn't be any fan
out problem, but I am not aware what is the readily available divider
to choose. The counter is mentioned on
http://home.online.no/~la8ak/m21.htm , but it is Norwegian text

hpe 2 hr fm u

73
Jan-Martin, LA8AK
http://home.online.no/~la8ak/d.htm
--
remove ,xnd to reply (Spam precaution!)

Search through Goggle groups in sci.electronics.design for a divide
by 3 counter, and follow it with five stages of divide by 2 counters.


96/3 = 32
32/2 = 16
16/2 = 8
8/2 = 4
4/2 = 2
2/2 = 1

You want the odd counter somewhere before the final stage to maintain a
50% duty cycle.
--


Michael A. Terrell
Central Florida

J M Noeding wrote:

Hi

for my quite unstable counters I've got some 0.1ppm 9.6MHz VCXO's
(guaranteed over temperature range -20...+20°C), the problem is that
the original XO is 1MHz with 7490 divider, and now I need a divide by
96 downcounter. The VCXO drives a 74LS14, so it shouldn't be any fan
out problem, but I am not aware what is the readily available divider
to choose. The counter is mentioned on
http://home.online.no/~la8ak/m21.htm , but it is Norwegian text

hpe 2 hr fm u

73
Jan-Martin, LA8AK
http://home.online.no/~la8ak/d.htm
--
remove ,xnd to reply (Spam precaution!)

Search through Goggle groups in sci.electronics.design for a divide
by 3 counter, and follow it with five stages of divide by 2 counters.


96/3 = 32
32/2 = 16
16/2 = 8
8/2 = 4
4/2 = 2
2/2 = 1

You want the odd counter somewhere before the final stage to maintain a
50% duty cycle.
--


Michael A. Terrell
Central Florida

"J M Noeding" wrote in message
...

for my quite unstable counters I've got some 0.1ppm 9.6MHz VCXO's
(guaranteed over temperature range -20...+20°C), the problem is that
the original XO is 1MHz with 7490 divider, and now I need a divide by
96 downcounter. The VCXO drives a 74LS14, so it shouldn't be any fan
out problem, but I am not aware what is the readily available divider
to choose. The counter is mentioned on
http://home.online.no/~la8ak/m21.htm , but it is Norwegian text

The 74HC4059 (or 74HCT4059) should do the trick. It may be a bit hard to
find, but will divide by any number from 3 to 16384. It is logically the
same as the RCA CD4059, but I don't think the old RCA part will work at your
frequency. I can't find my data book right now.

73 de bob w3otc

"J M Noeding" wrote in message
...

for my quite unstable counters I've got some 0.1ppm 9.6MHz VCXO's
(guaranteed over temperature range -20...+20°C), the problem is that
the original XO is 1MHz with 7490 divider, and now I need a divide by
96 downcounter. The VCXO drives a 74LS14, so it shouldn't be any fan
out problem, but I am not aware what is the readily available divider
to choose. The counter is mentioned on
http://home.online.no/~la8ak/m21.htm , but it is Norwegian text

The 74HC4059 (or 74HCT4059) should do the trick. It may be a bit hard to
find, but will divide by any number from 3 to 16384. It is logically the
same as the RCA CD4059, but I don't think the old RCA part will work at your
frequency. I can't find my data book right now.

73 de bob w3otc

"J M Noeding" wrote in message
...

for my quite unstable counters I've got some 0.1ppm 9.6MHz VCXO's
(guaranteed over temperature range -20...+20°C), the problem is that
the original XO is 1MHz with 7490 divider, and now I need a divide by
96 downcounter. The VCXO drives a 74LS14, so it shouldn't be any fan
out problem, but I am not aware what is the readily available divider
to choose. The counter is mentioned on
http://home.online.no/~la8ak/m21.htm , but it is Norwegian text


Oops, I may be wrong about the maximum division ratio of the 4059, but it is
certainly as large as 4 decimal digits (not binary). Again, I can't find my
data book right now.

73 de bob w3otc

"J M Noeding" wrote in message
...

for my quite unstable counters I've got some 0.1ppm 9.6MHz VCXO's
(guaranteed over temperature range -20...+20°C), the problem is that
the original XO is 1MHz with 7490 divider, and now I need a divide by
96 downcounter. The VCXO drives a 74LS14, so it shouldn't be any fan
out problem, but I am not aware what is the readily available divider
to choose. The counter is mentioned on
http://home.online.no/~la8ak/m21.htm , but it is Norwegian text


Oops, I may be wrong about the maximum division ratio of the 4059, but it is
certainly as large as 4 decimal digits (not binary). Again, I can't find my
data book right now.

73 de bob w3otc

On Tue, 18 Nov 2003 01:27:56 GMT, (J M Noeding)
wrote:

for my quite unstable counters I've got some 0.1ppm 9.6MHz VCXO's
(guaranteed over temperature range -20...+20°C), the problem is that
the original XO is 1MHz with 7490 divider, and now I need a divide by
96 downcounter. The VCXO drives a 74LS14, so it shouldn't be any fan
out problem, but I am not aware what is the readily available divider
to choose. The counter is mentioned on
http://home.online.no/~la8ak/m21.htm , but it is Norwegian text

Isn't the 74(LS)92 divide by 12 counter available anymore ? With an
addition of a 74(LS)93 divide by 16 counter (divide by 192 total), you
can get the required divide by 96 ratio, if you skip the independent
divide by 2 section from either the '92 or '93.

If you can not get the '92, get two '93 chips, let the first divide by
16 down to 600 kHz. Using only the divide by 8 part of the second '93,
detect the "6" count with a two input AND/NAND gate and reset the
counter. IIRC, the '93 contains a built in two input NAND gate in the
reset circuit, so these inputs needs only be connected to the two most
significant outputs of the divide by 8 counter. The required 100 kHz
output can be taken from the most significant output (it has a 66:33
output ratio). If you need 50:50 ratio, first divide by 8 in the first
'93, then by 6 in the second '93 and then by two in the independent
section in the first '93.

Paul OH3LWR

On Tue, 18 Nov 2003 01:27:56 GMT, (J M Noeding)
wrote:

for my quite unstable counters I've got some 0.1ppm 9.6MHz VCXO's
(guaranteed over temperature range -20...+20°C), the problem is that
the original XO is 1MHz with 7490 divider, and now I need a divide by
96 downcounter. The VCXO drives a 74LS14, so it shouldn't be any fan
out problem, but I am not aware what is the readily available divider
to choose. The counter is mentioned on
http://home.online.no/~la8ak/m21.htm , but it is Norwegian text

Isn't the 74(LS)92 divide by 12 counter available anymore ? With an
addition of a 74(LS)93 divide by 16 counter (divide by 192 total), you
can get the required divide by 96 ratio, if you skip the independent
divide by 2 section from either the '92 or '93.

If you can not get the '92, get two '93 chips, let the first divide by
16 down to 600 kHz. Using only the divide by 8 part of the second '93,
detect the "6" count with a two input AND/NAND gate and reset the
counter. IIRC, the '93 contains a built in two input NAND gate in the
reset circuit, so these inputs needs only be connected to the two most
significant outputs of the divide by 8 counter. The required 100 kHz
output can be taken from the most significant output (it has a 66:33
output ratio). If you need 50:50 ratio, first divide by 8 in the first
'93, then by 6 in the second '93 and then by two in the independent
section in the first '93.

Paul OH3LWR

Hi,

Have a look at the 74HCT40103 on the Philips site. Although
the output is asymmetric, it will divide by any number between 2
and 255.


Cheers - Joe