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Remote Control Decoder
PT2272
IR OPERATION
In the IR Type of Operation, the functions are similar to the above descriptions, except that the output
waveform carried by PT2262-IR has a frequency of 38KHz. Details are as follows.
CODE BITS
The Code Bits are further modulated with a 38KHz carrier frequency and can be “0”, “1” or “f” bit. Their
waveforms are shown in the diagram below.
OSC
160
0
20
1
60
f
Sync
20
620
Note: = 2 clock lengths
CODE WORD
A Code Word is made up of code bits and the format is the same as that of the RF Code Frame.
CODE FRAME
Likewise, a Code Frame is made up of Code Words and the format is the same as that of RF Type of
Operation.
OSCILLATOR
PT2262-IR is specially designed for infrared remote control applications and its output waveform
carries 38KHz frequency. To get the 38KHz carrier frequency at the data output, the oscillator
frequency must be 76KHz. A 440KΩ resistor connected between OSC1 and OSC2 pins of PT2262-IR
is recommended. Moreover, for a matching decoder frequency, 1MΩ resistor connected between the
OSC1 and OSC2 pins of PT2272 is also recommended.
PT2272 V3.7
- 9 -
June, 2008
PTC [ PRINCETON TECHNOLOGY CORP ]
