Pete KE9OA wrote:
snipped

On the subject of the R75, I know, the sync detector isn't the best in the
world

Pete,

Have you thought about incorporating one of your sync' detector designs
to the R75? It might prove to be the ultimate sync' mod for it.


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starman wrote in message ...
Pete KE9OA wrote:
snipped

On the subject of the R75, I know, the sync detector isn't the best in the
world

Pete,

Have you thought about incorporating one of your sync' detector designs
to the R75? It might prove to be the ultimate sync' mod for it.

Yes an maybe better than the R8b sync det [a very good one]
but not perfect Pete is a great designer and he inspired and working
very hard now in his sync det project.My own R-75 sync det [with a 339
comparator mod] is working for me an greatly reduce fading distortion
and diminishing and eliminating adjacent channel interference and is
sideband selectable [manually] using a 2.4 stock filter and selecting
manually [with the twin PBT] the less interfered of the two
sideband.Yes the R8b sync use a different aut sync circuity but if my
R75 sync det is working ok, then what is the motive for keep yearning
for the "ultimate sync"?

In article ,
(Kenneth) wrote:

starman wrote in message
...
Pete KE9OA wrote: snipped

On the subject of the R75, I know, the sync detector isn't the
best in the world

Pete,

Have you thought about incorporating one of your sync' detector
designs to the R75? It might prove to be the ultimate sync' mod for
it.

Yes an maybe better than the R8b sync det [a very good one]
but not perfect Pete is a great designer and he inspired and working
very hard now in his sync det project.My own R-75 sync det [with a
339 comparator mod] is working for me an greatly reduce fading
distortion and diminishing and eliminating adjacent channel
interference and is sideband selectable [manually] using a 2.4 stock
filter and selecting manually [with the twin PBT] the less interfered
of the two sideband.Yes the R8b sync use a different aut sync
circuity but if my R75 sync det is working ok, then what is the
motive for keep yearning for the "ultimate sync"?

Keep dreaming about making the R75 sync as well as the R8B. And be sure
to show some objective tests when you get a chance.

I traded in a R8 for an R8B for the design improvements in the sync
circuits.

--
Telamon
Ventura, California

It might be a good thing, if only I could get one of them to work properly.
The quasi-sync detector has been the best sounding one so far, but it is no
better than the TDA1572's balanced detector.
The 4046/SA602 detector still needs some work.................I think that
Phase Detector 2 is unsuitable for this purpose. I need to use Phase
Detector 1, which shifts the VCO by 90 degrees. This could work, if I can
come up with a suitable phase shift network.
I just completed the intial design of the AD607 based sync detector, and
boy, does this one have problems! When I am tuned to center channel, the
system howls, but if I detune to either LSB or USB, everything is ok. This
circuit is based on Mike Murphys application note from Analog Devices. It
just may work out, with some fine tuning. This has been the best iteration
so far. Analog Devices has eliminated the AGC detector in the latest
versions of the AD607, whereas Mr. Murphy's design is based on one of the
older versions that does have this detector. I do have some samples of the
older version, so I will throw that on the board tomorrow, and see how it
works out.
Those sync detectors have been the hardest part of this radio design!
Compared to my current iterations, the Icom R75 sync detector is a gem. This
gives you an idea of just how bad my sync detectors are! I'll get them
running.........they are only a collection of parts!

Pete

starman wrote in message
...
Pete KE9OA wrote:
snipped

On the subject of the R75, I know, the sync detector isn't the best in
the
world

Pete,

Have you thought about incorporating one of your sync' detector designs
to the R75? It might prove to be the ultimate sync' mod for it.


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Pete KE9OA wrote:

Those sync detectors have been the hardest part of this radio design!
Compared to my current iterations, the Icom R75 sync detector is a gem. This
gives you an idea of just how bad my sync detectors are! I'll get them
running.........they are only a collection of parts!

You're learning why so few receivers have been made with a good sync'
detector.
Keep up the good work.


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Thanks! it has been a learning experience!

Pete

starman wrote in message
...
Pete KE9OA wrote:

Those sync detectors have been the hardest part of this radio design!
Compared to my current iterations, the Icom R75 sync detector is a gem.
This
gives you an idea of just how bad my sync detectors are! I'll get them
running.........they are only a collection of parts!

You're learning why so few receivers have been made with a good sync'
detector.
Keep up the good work.


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I haven't heard from you, so I will assume that you did receive the info.

Pete

starman wrote in message
...
Pete KE9OA wrote:

Those sync detectors have been the hardest part of this radio design!
Compared to my current iterations, the Icom R75 sync detector is a gem.
This
gives you an idea of just how bad my sync detectors are! I'll get them
running.........they are only a collection of parts!

You're learning why so few receivers have been made with a good sync'
detector.
Keep up the good work.


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Pete KE9OA wrote:

I haven't heard from you, so I will assume that you did receive the info.

Pete

I got them Pete. Thanks a lot. I haven't studied the schematic too much
but I was wondering what changes (if any) would be needed to use the
sync' detector with a 50-Khz I.F.?


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I am glad that you received the data.............anyway, this chip is
specified as going down to 400kHz. I know that the phase detector requires a
higher drive level as you go lower in frequency. As an example, it requires
800mV p-p at 455kHz. I am not sure how much it would need at 50kHz, or it it
would even work. You would need to replace the 455kHz ceramic filters with
some sort of 50kHz filter if you wanted to keep the noise floor low, at the
very least.

Pete

starman wrote in message
...
Pete KE9OA wrote:

I haven't heard from you, so I will assume that you did receive the
info.

Pete

I got them Pete. Thanks a lot. I haven't studied the schematic too much
but I was wondering what changes (if any) would be needed to use the
sync' detector with a 50-Khz I.F.?


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