SIGNALS, SPECTRA, SIGNAL PROCESSING

From the word “commnicare” which means to share. it involves 2 parties - the sender and receiver. It takes many forms

Guided or Wired such as coax, UTP, Twin-Lead, Fiber Optics, Wave Guide, and many more.

Unguided or Wireless such as antenna and other radiators

It starts with tranducer, then transmitter, channel, to the receiver, and finally to Transducer.

Any device that converts from one form to another (e.g sond to electrical)

The band of frequencies occupied by the signal in a carrier system before it modulates the carrier frequency.

300 Hz to 3kHz

20hz to 20kHz

Ability to replicate its input to its output

Physical quantity or variable and typically contains information about the behavior or nature of the phenomenon. It starts with information, data, then signal (something that the senses can sense), message, representation, then the meaning.

Continuous signal in both time and amplitude. Electrical properties used are voltage, followed closely by frequency, current and charge

Discrete (mathematically, finite and countavle infinite) in both time and signal

Selecting values of an analog signal at a discrete time instant. First step when performing from analog to digital signal conversion

Easier to store, Immune to Noise, Have error detection and correction, and Encryption can be added.

Wider bandwidth and Complex Circuit

Number of bits used to store each intensity defies the accuracy of the digital signals

Classification of signal that is continuous and real in domain and range

Clasification of signal that often identifies as a sequence of numbers

A bandwidth continuous time signal can be sampled and perfectly reconstructed from its sample if the waveform is sample over twice as the highest frequency component

Effect produced when a signal is imperfectly reconstructed from the sampled signal. it occurs when a signal is not sampled at a high enough frequency to create an accurate representation

Classification of signal if it is purely real or signal has an imaginary part

Classification of signal whose values are completely specified for any given amount of time or signals that take random values at any given time.

Classification of signal if the signal have 1 flip or 2 flips

Classification of signals that tells if it is repeating or non-repeating (all random)

Classification of signal that has finite duration and ampitude

Classification of signal which states that signal is not limited in time, non zero for infinite amount of time.

Classification of signal that describe signal that does not start before t=0

Classsification of signal that describe signal that ends at t=0

Classification of signal that describes signal that starts before

Signal manipulation where signal can be delayed or advanced

Signal manipulation where signal is reversed in n value of t

Signal manipulation where the is upscaling (expand k times) or downsampling (compress k times)

Physical device that performs an operation on a given signal

If the output y[n] at every value of n depends only on the input x[n] atthe same value of n. Else, with memory, if with delay or advance.

If distinct inputs lead to distinct outputs or if an inverse system exist. Else, non-invertible.

Output does not depend on future input. Else, non-causal, if output depends on future input

If and only if every bounded input proceduces a bounded output. output of a stable system does not change reasonably. Else, unstable, even if one bounded input generates an unbounded output

Either homogeneous or additive

A shift in the inout signal results to an identical shift in the output signal