In modern measurement systems, the various components comprising the system are usually located at the distance from each other. It is, therefore, becomes necessary to transmit the data and information between them through some form of communication channel.
Telemetry may be defined as measurement at a distance.
Telemetry is indicating, recording, integrating a quantity at a distance by electrical means.
Telemetry is a technology which enables a user to collect data from several measurement points that are an inaccessible or inconvenient source, to transmit the data to a convenient location and present the several individual measurements in a usable form.
The general block diagram of a telemetry system is shown below. The telemetry system consists of the primary sensing element, telemeter transmitter, telemeter channel, telemeter receiver, and end device.
Classification of Telemetry(or data transmission)
1. On the basis of Domain
- Hydraulic transmission Telemetry
- Pneumatic Telemetry
- Electrical & Electronic Telemetry
2. On the basis of characteristics of electrical signal
- Current Telemetry
- Voltage Telemetry
- Frequency Telemetry
- Position Telemetry
- Pulse Telemetry
3. On the basis of type of transmission
- Analog Telemetry
- Digital Telemetry
4. On the basis of Distance
- Short distance Telemetry
- Long distance Telemetry