02 - Analog and Digital Signals

Analog Signals

Continuous and vary smoothly over time.

Digital Signals

Discrete and represented as binary values. Essential for computers and digital electronics.

Simple Periodic Signal

It is a sine wave that cannot be discomposed into simpler signals. Most basic building block of a signal.

Composite Periodic Analog Signal

Composed of multiple sine wave.

Sine Wave

The most fundamental form of a periodic signal. Can be represented by peak amplitude, frequency and phase.

Peak Amplitude

It is the absolute value of its highest intensity in a signal.

Period

The amount of time to complete one cycle of a signal.

Frequency

The number of cycles per second. 1/T

Phase

Describes the position of the waveform relative to time.

Wavelength

Binds the period or the frequency to the propagation speed of a medium.

Bandwidth

Range of frequencies contained in a composite signal. Represented in Hz.

Digital Signal

Signals that represent information using discrete values usually in binary.

Bit Rate

Used to describe digital signals, it is the information capacity.

Bit Length

Physical distance that one bit occupies on the transmission medium.

Baseband Transmission

It sends the digital signal over a channel without changing the digital signal to an analog signal.

Broadband Transmision

It changes the digital signal to an analog signal for transmission.

Attentuation

Means loss of energy. Measured in dB.

Distortion

It is when a signal changes its form or shape.

Thermal Noise

Random motion of electrons in a wire which creates an extra signal not originally sent by the transmitter.

Induced Noise

Comes from sources such as motors and appliances. They act as a sending antenna and the transmission medium is the receiving antenna. Radiation and such.

Crosstalk

Effect of one wire on another. Sending and receiving antennas.

Impulse Noise

Noise. A spike that comes from power lines, lightning, and so on.

Signal to Noise Ratio

A ratio of signal power over noise power. High means less distortion, low means high distortion.