Concepts and data transmission rates using the Ir Data transmission Protocol
Some important concepts in understand infrared data transmission should be understood.
The first is which is PWM, or Pulse Width Modulation, used in many devices, some of which are controlled by motors. IR detectors send a low rate of pulses, which can be measured to determine the message a IR remote device is sending.
IR remotes use carrier signals of 38.5 kHZ, to send durations of pulse to IR detectors. IR data transmission protocols can be defined as rules meant for exchanges of electronically generated messages to be transmitted from one device to another. Protocols determine the rate of voltage, the time that signals should last for, frequency of carrier signals, etc. When such rules are followed by two or more devices, this is known as a protocol and it allows an exchange of data.
IR messages are interpreted logically, as they represent the sequences of pulses as part of bit sequence. If we take an example of IR message having 13 pulses determined to work with the beginning pulse lasting for 2 – 4 ms the 2 – 13 pulses will last 1.2 ms if it is a binary 1 or 0.6 ms if the data sent is a binary 0.
A widelu used example of low-cost technology of data transmission is apparent in a television remote controls. Distances and bit rate are the trade-off in this technology. TV remote control signals are normally transmitted unidirectionally, and in case you have a bidirectional application, you will require high bandwidth in your detecting device.
Such infrared data transmission standards are defined by the IrDA industry based group, which has contributed low cost, point to point, transmission systems for such devices as laptops, handheld computers, printers, etc. Thus IrDA is identified as Infrared Data network protocol, which adapts a layered approach, dealing with controllable responsibilities, apart from providing capability to the layers.