Hi All,
When 2.4GHz short range module boots up, senses the temperature, adjusts the RF parameters itself.
What's the effect by temperature ?
Best regards, Boki.
- posted
16 years ago
Temperature effect on 2.4GHz RF
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- posted
16 years ago
Boki wrote in news: snipped-for-privacy@g37g2000prf.googlegroups.com:
temp changes will alter tuned elements that determine the oscillating frequency. semiconductor junctions change with temp,capacitance changes.
-- Jim Yanik jyanik at kua.net
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16 years ago
2000prf.googlegroups.com:
Ya, I believe it.
However, I think the effect should very small, or should be de-effect by other components.
It seems our module try to adjust digital algorithm to fit the changes.
However, I can't make sure that.
Boki.
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- posted
16 years ago
The carrier frequency will normally be generated with a PLL so it will be locked to a crystal. Since it has a crystal oscillator, it will probably re-tune itself using the crystal as the reference frequency to adjust the L-C circuits. These things have to be made so that they will work with maybe 20% manufacturing tolerance on the capacitors so the automatic adjustment facility is already needed anyway in many cases. The inductance value of the on-chip inductors is defined by lithography so it is very accurate and stable but the capacitor tolerance is set by the thickness of deposited layers and hence the wide tolerance. The series resistance of the inductors (and hence the Q) is quite temperature dependent, like the resistivity of most metals. They might calibrate this out as well.
Chris