5
DEMO MANUAL DC112A
OPERATIO
U
IrDA-FIR
With the exception of data rate and pulse width, FIR is very
similar to SIR (see Figure 4a). The same precautions about
interference from the other output apply to FIR and SIR.
The first FIR photo, Figure 4b, shows the receiver at a
range of 1 meter. The second photo, Figure 4c, shows the
receiver 1cm from the transmitter. Again, a detected light
pulse will make the receiver switch to a TTL LOW state.
TRANSMITTER
INPUT
RECEIVER
OUTPUT
RECEIVER
OUTPUT
TRANSMITTER
INPUT
IrDA-FIR (1m)
IrDA-FIR (1cm)
Figure 4. IrDA-FIR Modulation
0
1
0
0
1
1
0
1
0
1328 F03a
NRZ DATA
IrDA-FIR HIGH = LIGHT TRANSMITTED
DATA RATES: FIXED AT 1.15MBAUD
BIT INTERVAL: 870ns
PULSE WIDTH: 1/4 OF INTERVAL OR 217ns
4a
4c
4b
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