Antenna Analyzer AIM4170 page 34
The following discussion goes into more detail about the crystal calculations.
After the resonant frequencies are located, you can change the scan limits to focus in
more detail on the region of interest.
At the series resonant frequency, the reactances of L and Cs cancel out and the magnitude
of the impedance becomes equal to R. Therefore, the series resistance of the crystal can
be read directly at the minimum value of Zmag on the graph; the numeric value is Rs in
the Data Window.
At frequencies well below the series resonant point, the impedance value is the total
capacitance, Ctotal, which is essentially equal to Cparallel.
Ctotal approx = 4.5 pf
The value of Cseries is given by:
Cseries = Ctotal * 2 * (Freq_parallel - Freq_series ) / Freq_parallel
Where Freq_parallel is the parallel resonant frequency and Freq_series is the series
resonant frequency.
To Next Page
Loading...
