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Remote Control Encoder
PT2260
FUNCTION DESCRIPTION
PT2260 encodes the code address and data set at A0 ~ A7, A8/D3, A9/D2, D1 and D0 into a special
waveform and outputs it to the DOUT when any of the data pins is tied to high. This waveform is fed to
the RF modulator for transmission. The transmitted radio frequency is received by the RF demodulator
and reshaped into the special waveform. PT2270 (or PT2272) is then used to decode the waveform
and set the corresponding output pin(s). Thus completing a remote control encoding and decoding
function.
RF OPERATION
CODE BITS
A Code Bit is the basic component of the encoded waveform, and can be classified as either an AD
(Address/Data) Bit or a SYNC (Synchronous) Bit.
Address/Data (AD) Bit Waveform
An AD Bit can be designated as Bit “0”, “1”, or “f” if it is in low, high or floating state respectively. One bit
waveform consists of 2 pulse cycles. Each pulse cycle has 512 oscillating clock periods. For further
details, please refer to the diagram below:
α
O SC
1 b it = 1 0 24
α
B it " 0 "
B it " 1 "
3 8 4α
B it " f"
Flo a t ing
1 2 8α
1 2 8α
where:
α=Oscillating
Clock Period
Synchronous (Sync.) Bit Waveform
The Synchronous Bit Waveform is 4 bits long with 1/8 bit width pulse. Please refer to the diagram
below:
1 / 8 b it w id t h = 1 28
α
4 b its w idt h = 4 0 96
α
Note: 1 bit=1024α
PT2260 V1.4
-5-
April, 2006
PTC [ PRINCETON TECHNOLOGY CORP ]
