Transmitter:- It is a device to sense any kind of input like pressure, temperature, velocity, pulse,moisture, humidity etc. The transmitter converts the above parameters into required output like mA, mV, in the specified range. Receiver : It is device o receive the signal from the trasmitters (in the specified frequency level on both the transmitter and receiver) and send it to the processor to give the output. By T. PONNAMBALAM, CHENNAI