Rainbow Electronics MAX66020 - Manual (Page 8)

MAX66020
ISO/IEC 14443 Type B-Compliant
1Kb Memory Fob
8 _______________________________________________________________________________________
DATA TO BE TRANSMITTED
INDICATES 180 ° PHASE CHANGE (POLARITY REVERSAL)
OR
1 1 0
847kHz SUBCARRIER
BPSK MODULATION
TRANSMISSION OF A SINGLE BIT
POWER-UP DEFAULT = EIGHT CYCLES OF 847kHz (9.44 μs)
CAN BE REDUCED TO FOUR, TWO, OR ONE SUBCARRIER CYCLES FOR COMMUNICATION IN THE ACTIVE STATE.
Figure 9. Uplink: BPSK Modulation of the 847.5kHz Subcarrier
A
B
CARRIER AMPLITUDE
t
1 1 1 1 0 0
MODULATION INDEX M = = 0.08 TO 0.14
A - B
A + B
Figure 8. Downlink: 8% to 14% Amplitude Modulation