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Old July 23rd 05, 10:36 AM
doug dwyer
 
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In message , Mario Bros
writes
Hi folks,
I would have to ask a clarification regard to the TCXO.
They are found with output TTL, HCMOS and CLIPPED SINE WAVE.
It is just with respect to this last type that I would want to have
elucidations on when it is convenient to employ it, which the advantages and
the disadvantages and which the extension of spectral harmonicas.
In synthesis, from the plan point of view, which are the motivations that
they make to incline towards a Clipped oscillator?

Anticipated thanks.

73's de IK6GQC Rocco


I designed some of the first TCXOs , simple oscillators manufactured
they used no agc control and relied on the average oscillator
maintaining circuit gain to drop to limit oscillation level. Hence
clipped sine.
I.E gain during the transition and no gain during limiting.
This output then coupled to a buffer amp for isolation was the
Lowest cost option.
When logic compatibility was required a logic buffer or open collector
provided.
Also I note that (many years ago) when the first prototypes were
required I looked through a junk box for any small case and selected
most appropriate arbitary case.
These TCXO OCXO case dimensions can now be found as standard from many
TCXO / OCXO manufacturers around the world.
--
dd
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Old July 23rd 05, 10:50 AM
doug dwyer
 
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In message , Mario Bros
writes
Hi folks,
I would have to ask a clarification regard to the TCXO.
They are found with output TTL, HCMOS and CLIPPED SINE WAVE.
It is just with respect to this last type that I would want to have
elucidations on when it is convenient to employ it, which the advantages and
the disadvantages and which the extension of spectral harmonicas.
In synthesis, from the plan point of view, which are the motivations that
they make to incline towards a Clipped oscillator?

Anticipated thanks.

73's de IK6GQC Rocco


A further note the ssb noise will depend on the crystal Q the noise
level in the compensation circuit and the level of crystal oscillation.
Best with no compensation circuit ie XO or OCXO
The smallest crystals cannot be driven as hard as the bigger ones so
dont go for the smallest case!
The easiest way to indicate ssb noise may be to beat two identical
oscillators together with a few HZ offset.
Or lock one to the other using the voltage control line (exclusive or is
the easiest PLL circuit?)
The display the lock voltage on a scope.


--
dd
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Old July 23rd 05, 01:51 PM
Mario Bros
 
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Hi Doug,
A lot interesting. Thanks for the ulterior contribution.
In these days I will make some test in order to try the better
solution.

73's de IK6GQC Rocco

"doug dwyer" ha scritto nel messaggio
...
In message , Mario Bros
writes
Hi folks,
I would have to ask a clarification regard to the TCXO.
They are found with output TTL, HCMOS and CLIPPED SINE WAVE.
It is just with respect to this last type that I would want to have
elucidations on when it is convenient to employ it, which the advantages
and
the disadvantages and which the extension of spectral harmonicas.
In synthesis, from the plan point of view, which are the motivations that
they make to incline towards a Clipped oscillator?

Anticipated thanks.

73's de IK6GQC Rocco


A further note the ssb noise will depend on the crystal Q the noise level
in the compensation circuit and the level of crystal oscillation.
Best with no compensation circuit ie XO or OCXO
The smallest crystals cannot be driven as hard as the bigger ones so dont
go for the smallest case!
The easiest way to indicate ssb noise may be to beat two identical
oscillators together with a few HZ offset.
Or lock one to the other using the voltage control line (exclusive or is
the easiest PLL circuit?)
The display the lock voltage on a scope.


--
dd



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