LRI64_07 Datasheet, PDF (11/52 Pages) STMicroelectronics – Memory TAG IC at 13.56 MHz, with 64-bit Unique ID and WORM user area, ISO15693 and ISO18000-3 Mode 1 compliant

LRI64
5
Communication signal from VCD to LRI64
Communication signal from VCD to LRI64
Communications between the VCD and the LRI64 involves a type of Amplitude Modulation
called Amplitude Shift Keying (ASK).
The LRI64 only supports the 10% modulation mode specified in ISO 15693 and ISO 18000-
3 Mode 1 standards. Any request that the VCD might send using the 100% modulation
mode, is ignored, and the LRI64 remains in its current state. However, the LRI64 is, in fact,
operational for any degree of modulation index from between 10% and 30%.
The modulation index is defined as (a-b)/(a+b) where a and b are the peak and minimum
signal amplitude, respectively, of the carrier frequency, as shown in Figure 4.
Table 2. 10% modulation parameters
Parameter
Min
hr
–
hf
–
Max
0.1 x (a-b)
0.1 x (a-b)
Figure 4. 10% modulation waveform
hf
hr
tRFF tRFSFL tRFR
a
b
t
Figure 5. “1-out-of-4” coding example
10
00
01
75.52 µs
75.52 µs
75.52 µs
AI06655B
11
75.52 µs
AI06659B
11/52