EST PART 1 Flashcards
Collection of electronic components and circuits designed to convert the information into a signal. It’s functions are: Encoding Compression, Error correcting operations, and Modulatation processes.
-TRANSMITTER
The reduction of signal amplitude as it passes over the transmission medium
-ATTENUATION
Random, undesirable electric energy that enters the communication. It can be also defines as any unwanted introduction of energy tending to interfere.
-NOISE
TYPES OF NOISE
- External
- Internal
It is introduces in the medium/channel and difficult to quantify.
-EXTERNAL
It is produced at the receiver resistor, diodes, transistor, wires.
-INTERNAL
TYPES OF EXTERNAL NOISE
- Industrial/man made noise
- Atmospheric/static noise
- Extraterrestrial/space noise
Occurs randomly at a frequency up to 600 MHz.
-INDUSTRIAL/MAN MADE NOISE
Caused by lightning discharges during the thunderstorms and other natural electrical disturbances occuring in earth’s atmosphere less severe above 30MHz.
-ATMOSPHERIC/STATIC NOISE
Can be observe between 8MHz to 1.5GHz.
-EXTRATERRESTRIAL/SPACE NOISE
TYPES OF INTERNAL NOISE
- Thermal noise
- Shot noise
- Flicker noise
Also called brownian noise. It is associated with the rapid and random movement of electrons within a conductor.
-THERMAL NOISE
Is caused by the random arrival of carriers at the output element of an electronic device, such as diode, FET, OR BJT
-SHOT NOISE
Noise found at low audio frequencies in transistors. Proportional to the emitter current and junction temperature. Inversely propotional to frequency.
-FLICKER NOISE
Process of altering some of the characteristics of the carrier wave by impressing the modulating signal either by amplitude, frequency, or by phase information.
-MODULATION
Is the process of recoversing the modulating signal back to modulated carrier.
-DEMODULATION
Also known as the information signal. It can be a voice/audio, picture/audio, and data.
-MODULATING SIGNAL
TYPES OF MODULATION
- Amplitude Modulation (AM)
- Angle Modulation
- Frequency Modulation (FM)
- Phase Modulation (PM)
It is a modulation process where in the amplitude of the carrier is made proportional to the instantaneous amplitude of the intelligence.
-AMPLITUDE MODULATION
It is a type of analog modulation where in the frequency or phase of the carrier is varied in accordance with the instantaneous amplitude of the modulating signal.
-ANGLE MODULATION
It is an angle modulation where the instantaneous frequency of a carrier is caused to vary by an amount proportional to the modulating signal amplitude.
-FREQUENCY MODULATION
Angle modulation where the phase angle of a carrier is caused to depart from its reference value by an amount proportional to the modulating signal amplitude.
-PHASE MODULATION
It is the process of transferring digital information (usually in binary form) between two or more points. Information that has been processed, organized, and stored is called data.
-DATA COMMUNICATION
It is a system of computers, computer terminals use to transmit and/or receive information between two or more locations.
-DATA COMMUNICATION NETWORK
These are set of rules governing the orderly exchange of data within the network or a portion of the network.
-DATA COMMUNICATION PROTOCOLS
It created the sets of rules and standards for graphics and document exchange and provide models for equipment and system compatibility, quality enhancement.
-INTERNATIONAL STANDARDS ORGANIZATION
Is one of four permanent parts of the internation telecommunications union based in geneva, switzerland.
-COMITE CONSULTATIF INTERNATIONALE DETELEGRAPHIE AT TELEPHONIE
Network and service operation, tariff and accounting principles.
-THE ITU-T
It is the name for a set of standards for communicatingamong computers. It is also to serve as a structural guideline for exchanging information between computers.
-OPEN SYSTEMS INTERCONNECTION
Adopted a seven layer communications architecture reference model. Each layer consists of specific protocols for communication.
-ISO AND ITU-T (CCITT)
It is used to amplify signals carried by a network. It is used to lengthen individual network segments to form a large extended network.
-REPEATER
Used to build a LAN by connecting different computers in a star/hierachal network topology.
-HUBS
There are two types of hubs
- Passive
- Active
The signal is forwarded as it is doesn’t need power supply.
-PASSIVE