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PT2272 V3.7

- 9 -

June, 2008

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.

160

20

60

20

620

OSC

0

1

f

Sync

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.