Functionality and Electrical Waveforms - Data Rates Up to and Including 115.2 kb/s

In Figure 11a, the signal to the left of the UART [0] will not be discussed. The signal between the UART and the Encoder/Decoder [1] is a bit stream of pulses in a frame comprised a Start Bit, 8 Data Bits, no Parity Bit and ending with a Stop Bit, as shown in Figure 11a. The signal at [2], between the Encoder/Decoder Module and the IR Transducer Module is shown in Figure 11b. The electrical pulses between the IR Transmit Encoder and the Output Driver & LED are 3/16 of a bit period in duration (or, for the slower signaling rates, as short as 3/16 of the bit period for 115.2 kb/s). Note that the IR Transmit Encoder and the Output Driver and LED pulses begin at the center of the bit period. The electrical pulses between the Detector & Receiver and the IR Receive Decoder are nominally of the same duration as those between the IR Transmit Encoder and the Output Driver & LED, but may be longer in some implementations. Thus, the electrical signals at [2] are analogs of the optical signals at [3]; an example of a nominal waveform is shown in Figure 11b. A "0" is represented by a pulse and a "1" is represented by no pulse.

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Maintained by John Loomis, last updated 17 November 2009