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DS785UM1
Copyright 2007 Cirrus Logic
IrDA
EP93xx User’s Guide
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17.5.1 Introduction
17.5.1.1 4PPM Modulation
Four position pulse modulation (4PPM) is used for the high-speed transmission rate of
4.0 Mbps. Payload data is divided into data bit pairs (DBPs) for encoding with LSBs
transmitted first. Each DBP is represented by one of four symbols (DDs) comprising a single
125 ms pulse within a 500 ms symbol period. The 125 ms quarters of a symbol are known as
“chips”. The resulting signal waveform for the four data DDs is shown in
and
and shows modulation of the byte, 10110001b which is constructed using four
DBPs.
Note: 1. Bits within each DBP are not reordered, but the least significant DBP is transmitted first.
Note: 2. A “chip” in the context of the FIR is one time slice in the Position Modulation (PPM)
symbol.
Figure 17-2. 4PPM Modulation Encoding
Summary of Contents for EP93 Series
Page 28: ...P 6 DS785UM1 Copyright 2007 Cirrus Logic Preface EP93xx User s Guide PP P ...
Page 162: ...5 36 DS785UM1 Copyright 2007 Cirrus Logic System Controller EP93xx User s Guide 55 5 ...
Page 576: ...15 18 DS785UM1 Copyright 2007 Cirrus Logic UART2 EP93xx User s Guide 1515 15 ...
Page 634: ...17 38 DS785UM1 Copyright 2007 Cirrus Logic IrDA EP93xx User s Guide 1717 17 ...
Page 648: ...19 6 DS785UM1 Copyright 2007 Cirrus Logic Watchdog Timer EP93xx User s Guide 1919 19 ...
Page 688: ...21 32 DS785UM1 Copyright 2007 Cirrus Logic I2S Controller EP93xx User s Guide 2121 21 ...
Page 790: ...27 20 DS785UM1 Copyright 2007 Cirrus Logic IDE Interface EP93xx User s Guide 2727 27 ...
Page 808: ...28 18 DS785UM1 Copyright 2007 Cirrus Logic GPIO Interface EP93xx User s Guide 2828 28 ...