Take a look at Analog Devices' line of DDS chips. Pretty much a one-chip
(needs ucontroller to drive it) digital solution to turn your 10MHz clock
into virtually any frequency below 5 MHz (in theory; below 4MHz in easy
practicality). The AD9834 only consumes 20mw at 3.3 VDC. There are many
other devices in the product line. Many have built-in comparators to produce
square-wave output.

Joe
W3JDR


"Mike W" wrote in message
...
I have a need to produce an accurate 4Mhz 50% dutycycle TTL squarewave
to use as a timebase.

I have a 10Mhz IQD frequency standard of suitable accuracy. How can I
divide this to produce the 50% duty cycle 4Mhz signal?. Is it even
possible with logic alone?. I can see how to mix with either 6Mhz or
14Mhz, but this then detracts from the required accuracy.

atb Mikw

"W3JDR" wrote in message
...
Take a look at Analog Devices' line of DDS chips. Pretty much a one-chip
(needs ucontroller to drive it) digital solution to turn your 10MHz clock
into virtually any frequency below 5 MHz (in theory; below 4MHz in easy
practicality). The AD9834 only consumes 20mw at 3.3 VDC. There are many
other devices in the product line. Many have built-in comparators to
produce
square-wave output.

Joe
W3JDR



Joe, I'd gladly use the Analog Devices DDS chips if they offered them in
something other than a SadoMasochistic Device (SMD) package. It's a darn
shame they can't make a limited run (say 10k) of some of these chips in a
PDIP package for hams and other r.f. experimenters.

If they put the AD9835 in a PDIP and sold it for about $10.00 (the TSSOP
packaged version sells for about $6, I think) , I'd buy a dozen for various
projects, but in the tiny SMD package they're nothing but useless to me.

I'm new to the newsgroup and am sure that this is not the first gripe about
SMD's, but I refuse to use them - not because I can't (at least not yet),
but because I don't want to endure the angst.
--
Chip
KC5UES
real E-mail Address:







-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

If they put the AD9835 in a PDIP and sold it for about $10.00 (the TSSOP
packaged version sells for about $6, I think) , I'd buy a dozen for various
projects, but in the tiny SMD package they're nothing but useless to me.

I'm new to the newsgroup and am sure that this is not the first gripe about
SMD's, but I refuse to use them - not because I can't (at least not yet),
but because I don't want to endure the angst.

Sounds like a good opportunity for an enterprising ham - fab up a
bunch of adapter boards (or buy 'em premade - I think Ares has
something like this), solder down the SMD parts, and sell the
resulting PDIP-compatible boards to interested homebrewers.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Chip,
I totally agree with you about the difficulty in handling fine-pitch SMD
parts. It's a sign of the times.

FYI, check out the DDS Daughterboard at www.njqrp.org. This is a DDS
application board kit with on-board clock oscillator (you could run it from
an external oscillator if you wish). There's also a link to a service that
will solder your DDS chip to your bare board for $6 in single quantities.

Joe
W3JDR

"ChipS" wrote in message
...

"W3JDR" wrote in message
...
Take a look at Analog Devices' line of DDS chips. Pretty much a one-chip
(needs ucontroller to drive it) digital solution to turn your 10MHz
clock
into virtually any frequency below 5 MHz (in theory; below 4MHz in easy
practicality). The AD9834 only consumes 20mw at 3.3 VDC. There are many
other devices in the product line. Many have built-in comparators to
produce
square-wave output.

Joe
W3JDR



Joe, I'd gladly use the Analog Devices DDS chips if they offered them in
something other than a SadoMasochistic Device (SMD) package. It's a darn
shame they can't make a limited run (say 10k) of some of these chips in a
PDIP package for hams and other r.f. experimenters.

If they put the AD9835 in a PDIP and sold it for about $10.00 (the TSSOP
packaged version sells for about $6, I think) , I'd buy a dozen for
various
projects, but in the tiny SMD package they're nothing but useless to me.

I'm new to the newsgroup and am sure that this is not the first gripe
about
SMD's, but I refuse to use them - not because I can't (at least not yet),
but because I don't want to endure the angst.
--
Chip
KC5UES
real E-mail Address:







-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

On Tue, 24 Feb 2004 22:39:26 GMT, "W3JDR" wrote:
FYI, I have bought two of the DDS Daughter boards from

http://www.njqrp.org/

and used a standard Weller soldering iron to build it, with the
exception of the SM DDS chip, installed by KitBuilders.. email



Excellent results, both from KitBuilders and the finished product.
For $19 for the kit and $6 for installing the chip I now have a 1Hz
resolution signal source..

Thanks George ( njqrp ) and Mike ( wa6ouw )

my apologies, I appear to have cut the text from W3JDR in its
totality. What I ascribed to Joe was in fact all my own work ;-(
sorry Joe..
On Tue, 24 Feb 2004 23:47:11 GMT, (Mike W)
wrote:

On Tue, 24 Feb 2004 22:39:26 GMT, "W3JDR" wrote:
FYI, I have bought two of the DDS Daughter boards from

http://www.njqrp.org/

and used a standard Weller soldering iron to build it, with the
exception of the SM DDS chip, installed by KitBuilders.. email



Excellent results, both from KitBuilders and the finished product.
For $19 for the kit and $6 for installing the chip I now have a 1Hz
resolution signal source..

Thanks George ( njqrp ) and Mike ( wa6ouw )

my apologies, I appear to have cut the text from W3JDR in its
totality. What I ascribed to Joe was in fact all my own work ;-(
sorry Joe..
On Tue, 24 Feb 2004 23:47:11 GMT, (Mike W)
wrote:

On Tue, 24 Feb 2004 22:39:26 GMT, "W3JDR" wrote:
FYI, I have bought two of the DDS Daughter boards from

http://www.njqrp.org/

and used a standard Weller soldering iron to build it, with the
exception of the SM DDS chip, installed by KitBuilders.. email



Excellent results, both from KitBuilders and the finished product.
For $19 for the kit and $6 for installing the chip I now have a 1Hz
resolution signal source..

Thanks George ( njqrp ) and Mike ( wa6ouw )

On Tue, 24 Feb 2004 22:39:26 GMT, "W3JDR" wrote:
FYI, I have bought two of the DDS Daughter boards from

http://www.njqrp.org/

and used a standard Weller soldering iron to build it, with the
exception of the SM DDS chip, installed by KitBuilders.. email



Excellent results, both from KitBuilders and the finished product.
For $19 for the kit and $6 for installing the chip I now have a 1Hz
resolution signal source..

Thanks George ( njqrp ) and Mike ( wa6ouw )

"ChipS" wrote in message
...

"W3JDR" wrote in message
...
Take a look at Analog Devices' line of DDS chips. Pretty much a one-chip
(needs ucontroller to drive it) digital solution to turn your 10MHz
clock
into virtually any frequency below 5 MHz (in theory; below 4MHz in easy
practicality). The AD9834 only consumes 20mw at 3.3 VDC. There are many
other devices in the product line. Many have built-in comparators to
produce
square-wave output.

Joe
W3JDR



Joe, I'd gladly use the Analog Devices DDS chips if they offered them in
something other than a SadoMasochistic Device (SMD) package. It's a darn
shame they can't make a limited run (say 10k) of some of these chips in a
PDIP package for hams and other r.f. experimenters.

If they put the AD9835 in a PDIP and sold it for about $10.00 (the TSSOP
packaged version sells for about $6, I think) , I'd buy a dozen for
various
projects, but in the tiny SMD package they're nothing but useless to me.

I'm new to the newsgroup and am sure that this is not the first gripe
about
SMD's, but I refuse to use them - not because I can't (at least not yet),
but because I don't want to endure the angst.
--
Chip
KC5UES
real E-mail Address:







-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

In the case of RF devices like DDS's and high-performance microprocessors
(you think 1GHz isn't RF?) the surface mount package significantly enhances
performance. I haven't found them to be that bad to work with; you just
need good eyes and a steady hand.


--------------------------------------
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Yes Tim, I agree. Unfortunately, the physics of RF favors "small" and
"compact". This is the price we pay for such high performance. It's not yet
to the point where it's a 'show stopper' for experimenters, but you have to
be increasingly resourceful and persistent. Many have dropped out of
hombrewing at a time when the possibilities are most exciting, merely
because they can't or won't adapt to the new packaging technologies and the
need to learn a little about firmware programming in order to make the new
generation of parts work. It's not that they "can't" learn, it's mostly that
they "won't" learn.

Joe
W3JDR



In the case of RF devices like DDS's and high-performance microprocessors
(you think 1GHz isn't RF?) the surface mount package significantly
enhances
performance. I haven't found them to be that bad to work with; you just
need good eyes and a steady hand.


--------------------------------------
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com