JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech IV TELEMETRY AND TELECONTROL Previous Question Paper (February/March - 2022 - R16)

A basic telemetry system is designed to measure physical quantities at a remote location and transmit the data to a central station for monitoring or control. The process involves the following functional blocks:

1. Transducer/Sensor: Converts the physical parameter (e.g., temperature, pressure) into an electrical signal.
2. Signal Conditioning: Amplifies, filters, or linearizes the electrical signal to make it suitable for processing.
3. Multiplexer: If multiple sensors are used, the multiplexer sequentially selects signals to be transmitted over a single communication channel.
4. Transmitter: Modulates the signal onto a carrier wave for transmission via wire, fiber optics, or radio frequency.
5. Communication Channel: The medium through which the signal travels to the receiving end.
6. Receiver: Demodulates the carrier signal to recover the original electrical data.
7. Demultiplexer: Separates the multiplexed signals back into individual channels.
8. Data Processing/Display: The final stage where data is decoded, recorded, or displayed for human observation or automated control.

Error correcting codes are techniques used in digital communication to detect and fix errors that occur during data transmission due to noise or interference. By adding redundant bits to the original data, the receiver can identify the location of an error and correct it without needing retransmission.

Coding Gain: This is the improvement in the signal-to-noise ratio (SNR) provided by the use of error correction coding, allowing a system to achieve the same bit error rate with less transmitted power.

Bit Error Rate (BER): Defined as the ratio of the number of bits received in error to the total number of bits transmitted over a specified time interval; it is a primary metric for communication system reliability.

Block Code: A method of error control where information is divided into fixed-length blocks of length 'k', and each block is mapped into a longer codeword of length 'n' by adding 'n-k' parity bits, creating a structured relationship between data and redundancy.