R
EM4150
EM4350
Communication from the Transceiver to the Transponder (RECEIVE MODE)
(cont.)
While the transceiver is sending data to the transponder, two different modulations will be observed on both coils. During
the first half of the bit period, the EM4150 is switching "ON" its modulation device causing a modulation of the RF field. This
modulation can also be observed on the transceiver's coil. The transceiver sending a bit "0" will switch "OFF" the field,
causing a 100% modulation being observed on the transponder coil.
Bit
Period
DATA
:
"1"
"0"
"0"
"1"
"0"
"1"
Transceiver
Coil
Transponder
Coil
Periods of RF field (Opt 64):
Periods of RF field (Opt 32):
32
16
32
16
32
16
32
16
*
Modulation induced by the Transceiver
*
Recommended
Minimum
: 7/4 periods (Opt64/Opt32)
: 1 period
Modulation induced by the Transponder
Fig. 23
Copyright
©
2004, EM Microelectronic-Marin SA
11
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EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
