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Hi All again:
Note about TCXO and DTCXO.
73, José - EA1PX
----- Original Message -----
Sent: Saturday, November 30, 2002 2:33
PM
Subject: Re: LF: Osc drift (TCXO)
Hi,
In a message dated 11/29/02 7:03:23 PM GMT
Standard Time, [email protected]
writes:
Layout of the IIG oscillator/synthesizer board is quite
different from the
II, also the TCXO for the IIG is much bigger and a
different part number.
The TCXO for the II is claimed to be a
"numerically-controlled" type, that
for the IIG is not. Does anyone know
the difference? I thought all tcxo's
were just thermistor-controlled
varactor diodes in series with the crystal.
I think the
idea of a numerically-controlled TCXO is having an internal ADC digitizing the
NTC voltage, convert it in a calibrated nonvolatile lookup-table and then use
a DAC for the varicap. Depending on digital resolution, this concept can be
prone to a stepwise response to gradual temperature changes, possibly
resulting in a sawtooth FM pattern.
73
Markus,
DF6NM
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