Silan

Semiconductors

SC7461

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 2.2

2002-02-28.

8

5.SC7461 TRANSMISSION CODE

The SC7461 transmission code consists of a leader code, 13 bits custom code, and 8 bits key data codes. The

inverse code of both the custom and key data codes are also sent simultaneously; thus, allowing an extremely low

error rate in the system configuration. Please refer to the following diagram.

C0 C1 C2 C3

C5

C4

C6 C8

D0 D1 D2 D3 D4

D0 D1 D2 D3 D4 D5 D6 D7

D5 D6 D7

Leader Code

Custom Code (13 bits)

Custom Code (13 bits)

Key Data (8 bits)

Key Data ( 8 bits)

C9 C10 C11 C12

C11 C12

C10

C8

C7

C6

C5

C4

C3

C2

C1

C0

FIGURE 13. REM OUTPUT CODES

The leader code consists of a 9ms carrier waveform followed by a 4.5ms OFF waveform. It is used as the leader

for the following codes (Custom, Data and their respective inverse codes). Thus, when the reception is configured by

a microcomputer, the time relationship between the reception detection and other processes can be managed

efficiently. The code uses the PPM (Pulse Position Modulation) Method, with "1" and "0" differentiated by the time

between pulses.