DATA TRANSMISSION &TELEMETRY

NITTTR Sec-26CHANDIGARH

TELEMETRY

Submitted To Submitted By Chandresh KumarMrs. Ritula thakur ME.(E.E.I&C) Roll

No.141503(Modular)

CONTENT1. INTRODUCTION2. METHOD OF DATA TRANSMISSION3. BASIC TELEMETRY SYSTEM4. LAND LINE TELEMETRY SYSTEM5. R.F.TELEMETRY6. APPLICATION

INTRDUCTIONTelemetry is the highly automated

communication process by which measurement are made and other data collected at remote and transmitted to receiving

equipment for monitoring recording and analysis

Method of Data TransmissionThe method employed for data transmission

depend upon the variable& distance over which

data has to be transmitted1. Hydraulic Transmission2. Pneumatic Transmission3. Electrical and electronics Transmission

GENERAL TELEMETRY SYSTEM

Primary Sensing Element

TelemeterTransmitter

TelemeterChannel

TelemeterReceiver

Measurand

End Device

Type of Telemetry SystemA. Land line Telemetry System1. Voltage Telemetry System2. Current Telemetry System3 Position Telemetry System

B. Radio Frequency Telemetry System

Voltage Telemetry SystemTransmitting Terminal Receiving

Terminal

EEEEEEnb

Pointer on scale

Bourdon

Null balanc

e

potentiometer

R F Telemetry System (a) There is no physical link between Transmitting and

Receiving station (b) The transmitter comprises a RF modulator (AM or FM

type, depending on the performance, bandwidth and cost considerations) and an amplifier.

(c) The receiver comprises an amplifier and a demodulator (AM or FM type as required to match the type of the modulator).

REDIO FREQUENCY TELEMETRY

Telemetry System

Telemetry system:Collect data at a place (say microsatellite)Encode, modulate, and transmit the data to a remote station (say ground)Receive the data (on the ground)Demodulate, decode, record, display, and analyze the data

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Data collection: sensors, signal conditioners

Analog multiplexer & analog-to-digital converter

Synchronizer & Demultiplexer

Data processing and display

channel

Modulator, transmitter, antenna

Antenna, receiver, demodulator

Digital multiplexer Time tag

Data Formatter

On-board Storage

Modulation SchemesModulation

Variation of a periodic waveform to convey information

Modulation SchemesPulse ModulationAmplitude ModulationFrequency ModulationPhase Modulation

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Analog Modulation

Modulation: baseband signal → RF waveformRF waveform: A cos(wt+f) where w is the carrier frequency.Amplitude modulation (AM): vary A with baseband signalFrequency modulation (FM): vary d /f dt with baseband signalPhase modulation (PM): vary f with baseband signal

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Digital Modulation

Methods:ASK (Amplitude shift Keying)FSK (Frequency shift keying)PSK (Phase shift keying)QPSK (Quadrature phase shift keying)

0 1 100

Multiplexing

When a series of input signals from different sources have to be transmitted along the same physical channel, multiplexing is used to allow several communication signals to be transmitted over a single medium.Frequency division multiplexing (FDM)

FDM places multiple incoming signals on different frequencies. Then are they are all transmitted at the same time The receiving FDM splits the frequencies into multiple signals again

Time division multiplexing (TDM) TDM slices multiple incoming signals into small time intervals Multiple incoming lines are merged into time slices that are transmitted via satellite The receiving TDM splits the time slices back into separate signals

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TDM

A frame of data is formed for transmissionSync wordData words (slots)Error check words

Must considerSampling rateSlow and fast measurement dataResolution and bit rateFrame rate

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signal 1

Commutator

Multiplexer

signal 2

signal N

TDM bit stream

TimingFrame sync

frame

slotsync

FDM

IRIG standard:Proportional bandwidth (PBW): peak frequency deviation of the subcarrier is proportional to the subcarrier frequency

Constant bandwidth (CBW): the deviation is constant

CCITT multiplexing scheme: FDM telephone signals

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FM modulatorsignal 1

carrier f1

FM modulatorsignal 2

carrier f2

FM modulatorsignal N

carrier fN

Summer FDM signal

A multi-tone signal is formedMust consider

Frequency planPre-emphasis

Military Communications Architecture

APPLICATION1. Meteorology2.  Oil and gas industry3.  Space science4. Motor racing5. Agriculture6. Water management7.  Swimming Pools8. Defense, space and resource exploration9. Rocketry10.  Flight testing

1. Military intelligence2.  Energy monitoring3.  Resource distribution4.  Medicine/Healthcare5.  Fishery and wildlife research and

management6.  Retail7. Law enforcement8.  Energy providers9.  Falconry10. Testing11.Communication

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