ATA5283 ATMEL Corporation, ATA5283 Datasheet - Page 5

• Manufacturer Part Number: ATA5283
• Description: Interface ic For 125 KHZ Wake-up Function
• Manufacturer: ATMEL Corporation

Signal Conditioner
4598A–AUTO–04/03
The signal conditioner demodulates the amplifier output signal and converts it to a
binary signal. It compares the carrier signal with the 50% reference level (see Ref1 in
Figure 5) and delivers a logical 1, if the carrier signal stays below the reference and a
logical 0, if it exceeds the reference level. A smoothing filter suppress the space
between the half-waves as well as a few missing periods in the carrier and glitches dur-
ing the gaps.
The output signal of the signal conditioner is used as the internal data signal for the data
output, the wake-up logic and the preamble detection.
The timing of the demodulated data signal is delayed related to the signal at the trans-
mitting end. This delay is a function of the carrier frequency, the behavior of the
smoothing filter and the antenna Q-factor. The smoothing filter causes a delay of 3 to
6 periods (see t
of the antenna signal and is conditioned on the Q-factor (see t
Figure 5. Output Timing
Coil
input
Comparator
output
N_DATA
Ref.2
Ref.1
t
t
a
b
ON
and t
t
b
d
in Figure 5). The rest of the delay is caused by the build-up time
t
c
t
OFF
t
d
a
and t
c
in Figure 5).
ATA5283
100%
50%
5