EM4450

EM4550

Copyright

 2003, EM Microelectronic-Marin SA

12

www.emmicroelectronic.com

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 EM4450/4550 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.

Transceiver

Coil

Transponder

Coil

"1"

"1"

"1"

"0"

"0"

"0"

16

16

Periods of RF field (Opt 32):

Bit Period

DATA :

Modulation induced by the Transceiver

Modulation induced by the Transponder

16

*

Minimum

: 7/4 periods (Opt64/Opt32)

16

Periods of RF field (Opt 64):

32

32

32

32

: 1 period

Opt64 is the chip option with a bit period corresponding to 64 priods of the RF field

Opt32 is the chip option with a bit period corresponding to 32 priods of the RF field

Fig. 21