(CT) Communications Technologies Overview
Communications Technologies Overview
Introduction
When you review the flow chart you will note this is a transmission of a voice message from sender to receiver, demonstrating conversion of audio to electrical signals sent via a radio system. The reference “signal” is just voice, or audio. Transducers are signal conditioning devices. The representation shown in this figure is to convert the signal from audio to electrical or electrical to audio. The Electronic Processor conditions the electrical signal so it can be managed by the Transmitter, which in turn converts the signal to whatever form of transmission, in this case electromagnetic wave, i.e. radio. Or it can sometimes be optical for fiber optics. The Receiver does the reverse of the transmitter and converts back to electrical so the Transducer can convert to the form to be understood, in this case an audio signal.
The term “communications” can be understood in different ways. It means sending a message from one point to another. An example could be the Watch Towers to be set with signal fires that were used in ancient China to warn of invaders. Or another is the Semaphore system of signaling with flags, such as had been used for naval applications. However, in this module you will be introduced to Communication Technologies, which is the electrical engineering aspect of Communications.
Module Lessons Preview
In this module, we will study the following topics:
Common Terms
Analog Communication – information or signal that has continually variable values over time
Bandwidth – transmission capacity of communications system
Bit – a binary unit of information (either 1 or 0) in digital or data communications
Byte – a group of binary digits considered as one unit of information or a measurement of size
DC – Direct Current – electric current flowing in one direction only
Digital Communication – information flow of binary signals, logic values 1 or 0 per bit of information
Electromagnetic Waves – energy composed of both electric fields and magnetic fields
Frequency – rate of vibration of a wave
Network – interconnected communication devices
Noise – static or other sudden electrical impulses on a communications channel
Signal – a message or radio wave transmitted or received
Wavelength – the distance between successive crests of a wave
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