9
J.A.G Aug 2006
►
The Digital
Demodulator
z
The input frequency is measured by counting the oscillation clock for the time
period of the input signal.
z
The demodulator distinguishes between the high-bit frequency and the low-bit
frequency by the shift values and
not
by the absolute values.
z
The threshold between the high-bit and the low-bit is defined as 6.5 kHz lower
than that measured for the low-bit frequency
z
After the charge phase, the transponder response frequency is measured to
determine the counter state for the low-bit and high-bit threshold
VDD
SCIO
Digital
Demodulator
Transponder Resonance -
Frequency Measurement
SCI-
Encoder
