Staff Site Universitas Negeri Yogyakarta
TELEMETRY
INTRODUCTION
What Is Telemetry?
Telemetry is the process by which an object’s characteristics are
measured (such as velocity of an aircraft), and the results transmitted to
a distant station where they are displayed, recorded, and analyzed.
Several Good Definitions:
The measurement of some quantity with the aid of intermediate means
which permit the measurement to be interpreted at a distance from the
primary detector.
The process that measures a quantity and then transfers the
measurement data to a remote location to be recorded, displayed, or to
control a process. [Streich, p 1].
FCC Definition: "use of telecommunication for automatically indicating or
recording measurements at a distance from the measuring instrument."
[Horan, p 1]
Strictly speaking, "telemetry" is the information that is collected, and
"telemetering" is the process that collects and transfers the information.
[Horan, p 1]
TELEMETRY SYSTEMS OVERVIEW
A telemetering system includes all
components that are used to measure,
transfer, and analyze the data.
A telemetry system is often viewed as
two components, the Airborne System
and the Ground System.
AIRBORNE
Data acquisition begins when sensors
(transducers) measure the amount of a physical
attribute and transform the measurement to an
engineering unit value.
Sensors attached to signal conditioners provide
power for the sensors to operate or modify signals
for compatibility with the next stage of
acquisition.
Since maintaining a separate path for each source
is cumbersome and costly, a multiplexer
(historically known as a commutator) is employed.
TRANSDUCER
Transducers are used to transform a
physical parameter into an electrical
signal. There are several major
classifications of transducers [Horan, p
15, 16]:
Optical or Visual
Pressure, Strain, Force
Environmental
Position
AMPLIFIER
An instrument amplifier is used to
amplify the (usually) very small
electrical signal that is generated by a
transducer into a higher intensity signal
that is better suited for transmission.
MULTIPLEXER
The multiplexer is used to combine
several measurement signals into a
single signal to be transmitted to the
base station.
There are two primary types of
multiplexing--Time Division Multiplexing
(TDM) and Frequency Division
Multiplexing (FDM)
PULSE CODE MODULATOR
PCM encodes the amplitude of the
multiplexer output in digital form and
then transmits that signal.
Ability to add error correction codes
into the data stream to correct errors
that may occur during transmission.
TRANSMITTER
Transmits the signal that is generated
by the multiplexer.
The transmission can take place via
several different techniques depending
on the transmission medium.
INTRODUCTION
What Is Telemetry?
Telemetry is the process by which an object’s characteristics are
measured (such as velocity of an aircraft), and the results transmitted to
a distant station where they are displayed, recorded, and analyzed.
Several Good Definitions:
The measurement of some quantity with the aid of intermediate means
which permit the measurement to be interpreted at a distance from the
primary detector.
The process that measures a quantity and then transfers the
measurement data to a remote location to be recorded, displayed, or to
control a process. [Streich, p 1].
FCC Definition: "use of telecommunication for automatically indicating or
recording measurements at a distance from the measuring instrument."
[Horan, p 1]
Strictly speaking, "telemetry" is the information that is collected, and
"telemetering" is the process that collects and transfers the information.
[Horan, p 1]
TELEMETRY SYSTEMS OVERVIEW
A telemetering system includes all
components that are used to measure,
transfer, and analyze the data.
A telemetry system is often viewed as
two components, the Airborne System
and the Ground System.
AIRBORNE
Data acquisition begins when sensors
(transducers) measure the amount of a physical
attribute and transform the measurement to an
engineering unit value.
Sensors attached to signal conditioners provide
power for the sensors to operate or modify signals
for compatibility with the next stage of
acquisition.
Since maintaining a separate path for each source
is cumbersome and costly, a multiplexer
(historically known as a commutator) is employed.
TRANSDUCER
Transducers are used to transform a
physical parameter into an electrical
signal. There are several major
classifications of transducers [Horan, p
15, 16]:
Optical or Visual
Pressure, Strain, Force
Environmental
Position
AMPLIFIER
An instrument amplifier is used to
amplify the (usually) very small
electrical signal that is generated by a
transducer into a higher intensity signal
that is better suited for transmission.
MULTIPLEXER
The multiplexer is used to combine
several measurement signals into a
single signal to be transmitted to the
base station.
There are two primary types of
multiplexing--Time Division Multiplexing
(TDM) and Frequency Division
Multiplexing (FDM)
PULSE CODE MODULATOR
PCM encodes the amplitude of the
multiplexer output in digital form and
then transmits that signal.
Ability to add error correction codes
into the data stream to correct errors
that may occur during transmission.
TRANSMITTER
Transmits the signal that is generated
by the multiplexer.
The transmission can take place via
several different techniques depending
on the transmission medium.