Jim Hampton wrote:
Thanks for the tip, Carl. Geeze, Analog Devices. I should have remembered.
It has been quite a few years since I worked in Materials Engineering and
actually had a feel for the current state of the art. Heck, I was only off
by a factor of 10 on that clock rate! 10 percent is one thing, but by a
decade! LOL. Be grateful I didn't suggest wiring a bunch of 12AU7s
together in flip flops. Hmmm ... where'd I put that core memory anyways?
BTW, those 400 MHz devices are 10 cents per dozen, right?

All of the AD synthesizers I have seen have a microprocessor interface,
where they basically memory-map into a processor. I'd rather have something
I can directly address.

I could probably pull out a 68HC11 to control the thing if I absolutely had
to, but I'd rather have something I can just latch a BCD input into.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Scott Dorsey" wrote in message
...
Jim Hampton wrote:
Thanks for the tip, Carl. Geeze, Analog Devices. I should have
remembered.
It has been quite a few years since I worked in Materials Engineering and
actually had a feel for the current state of the art. Heck, I was only
off
by a factor of 10 on that clock rate! 10 percent is one thing, but by a
decade! LOL. Be grateful I didn't suggest wiring a bunch of 12AU7s
together in flip flops. Hmmm ... where'd I put that core memory anyways?
BTW, those 400 MHz devices are 10 cents per dozen, right?

All of the AD synthesizers I have seen have a microprocessor interface,
where they basically memory-map into a processor. I'd rather have
something
I can directly address.

I could probably pull out a 68HC11 to control the thing if I absolutely
had
to, but I'd rather have something I can just latch a BCD input into.
--scott

Modern DDS devices would require too many pins on the device for
cheap packages unless they used some sort of serial communications
or a modest pin count multiplexed bus.

I doubt that you will find anything useful with a straight binary or BCD
input because the devices need too many bits loaded into them to set
up all of the internal functions/registers.

Carl - wkc3

Carl R. Stevenson wrote:
--scott

Modern DDS devices would require too many pins on the device for
cheap packages unless they used some sort of serial communications
or a modest pin count multiplexed bus.

I doubt that you will find anything useful with a straight binary or BCD
input because the devices need too many bits loaded into them to set
up all of the internal functions/registers.

Right. I am looking for something that might best be implemented as
an ASIC somewhere, in that it would be a special-purpose sine wave
synthesizer rather than a general purpose DDS device.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Sheesh! 1 GHz with a 10 bit binary counter. Only $350.00 each in quantities
of 1000. Someone care to loan me over 1/3 of a million? Seriously,
however, there are affordable AMD devices but they appear to be in the 50
MHz to under 200 MHz range.

73 from Rochester, NY
Jim AA2QA


"Scott Dorsey" wrote in message
...
Carl R. Stevenson wrote:
--scott

Modern DDS devices would require too many pins on the device for
cheap packages unless they used some sort of serial communications
or a modest pin count multiplexed bus.

I doubt that you will find anything useful with a straight binary or BCD
input because the devices need too many bits loaded into them to set
up all of the internal functions/registers.

Right. I am looking for something that might best be implemented as
an ASIC somewhere, in that it would be a special-purpose sine wave
synthesizer rather than a general purpose DDS device.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."


---
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Jim Hampton wrote:
Sheesh! 1 GHz with a 10 bit binary counter. Only $350.00 each in quantities
of 1000. Someone care to loan me over 1/3 of a million? Seriously,
however, there are affordable AMD devices but they appear to be in the 50
MHz to under 200 MHz range.

I could do that. Generate a 50-80 Mhz sine wave, then put it into a mixer
with a 50 Hz crystal oscillator and turn it into a DC-30 Mhz signal. I
think I could even get a brickwall high pass at 30 MHz so the whole thing
would be broadband with no tuning.

Of course, you'd lose some stability in the process from those extra
stages, but probably not enough to be a big issue.

Oh, and for 10M FM, of course, I could modulate the local oscillator.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

ISTR that the programming interface for PLL chips is the three wire serial
form, with a static clock. you _COULD_ drive it with
three switches, but you'd have to at least debounce them -
RS flip-flop from NAND ususally being the simplest way.

Might be interesting to derive a driving circuit from
el-bug principles!

Scott Dorsey wrote in message
...
All of the AD synthesizers I have seen have a microprocessor interface,
where they basically memory-map into a processor. I'd rather have
something
I can directly address.
I could probably pull out a 68HC11 to control the thing if I absolutely
had
to, but I'd rather have something I can just latch a BCD input into.
--scott