Service manual

12. I/R communication circuit
• In the ER-A460/A470, infra-red data transmission of the optical
communication system is performed.
System IRDA ASK REMOTE KEYBOARD
Carrier wave 950 nm 900 ∼ 1050 nm 900 ∼ 950 nm
Sub-carrier wave (16 times of baud rate clock) 500 kHz±10% 33 ∼ 40 kHz
Modulation
system
"0": HIGH level
"1": LOW level
Only around the center of the bit cycle
in HIGH level, 3/16 of the bit cycle is
set HIGH, and the rest is set LOW.
Pulse modulation:
The pulse array of data code is
modulated by the AM system.
Pulse modulation:
The pulse array is modulated by data
codes in the PPM system.
Primary modulation:
The sub-carrier waveform is
amplitude-modulated with this pulse
array.
Primary modulation:
The sub-carrier waveform is
amplitude-modulated with this pulse
array.
Secondary modulation:
With the sub-carrier waveform which
was modulated in the primary
modulation, infra-red rays are
amplitude-modulated.
Secondary modulation:
With the sub-carrier waveform which
was modulated in the primary
modulation, infra-red rays are
amplitude-modulated.
Modulated
waveform
Baud rate 2.4 ∼ 115.2 kbps 9.6 ∼ 57.6 kbps (ZR-5000: 9600 bps) —
Serial
communication
system
Start-stop synchronization system
Data length: 8bit
Parity: None
Stop bit: 1
Start-stop synchronization system
Data length: 8bit
Parity: ODD
Stop bit: 1
—
Transmission
distance
About 0.75m: ECR to ECR
Min. 0.65m
About 0.75m: ECR to ECR
Min. 0.65m
About 1m
500KHz
"0" "1" "0" "1"
16-division
3/16
UART
Reverse
UART
IRDA
ASK
58.5~76.5 ms
108 ms
108 ms
9 ms
4.5 ms
13.5 ms
Leader Code
Custom Code
8 bits
Custom Code'
8 bits
Data Code
8 bits
27 ms
18 ms~36 ms
58.5 ms~76.5 ms
Data Code
8 bits
9 ms
4.5 ms
13.5 ms
1.125 ms
2.25 ms
0 11 0 01
9 ms
2.25 ms
11.25 ms
0.56 ms
Time is the value for 455kHz oscillation.
First
time
Carrier waveform
Carrier frequency.....fc=fosc/12=38 khz
Second time and later
(Transmitted only when the key is depressed.)
8.77µs
26.3µs
9 ms or 0.56 ms
<Remote keyboard>
0.56 ms
– 30 –