An analog or analogue signal is any continuous signal for which the time varying feature ( variable ) of the signal is a representation of some other time varying quantity, i. e., analogous to another time varying signal.

It differs from a digital signal, in which a continuous quantity is represented by a discrete function which can only take on one of a finite number of values.

In radio communication, a continuous wave radio-frequency signal ( a sinusoidal carrier wave ) has its amplitude modulated by an audio waveform before transmission.

* Analog signal processing, processing electronic signals that represent continuous variables by use of analog circuitry

Thus, an analog signal is one represented by a continuous stream of data, in this case along an electrical circuit in the form of voltage, current or charge changes ( compare with digital signals below ).

Analog signal processing ( ASP ) then involves physically altering the continuous signal by changing the voltage or current or charge via various electrical means.

Analog ( or analogue ) television is the analog transmission that involves the broadcasting of encoded analog audio and analog video signal: one in which the information to be transmitted, the brightness and colors of the points in the image and the sound waves of the audio signal are represented by continuous variations of some aspect of the signal ; its amplitude, frequency or phase.

Each station transmitted a continuous wave signal that, by comparing the phase difference of the signals from the Master and one of the Slaves, resulted in a set of hyperbolic lines of position called a pattern.

Group 1 and 2 faxes are sent in the same manner as a frame of analog television, with each scanned line transmitted as a continuous analog signal.

Mathematically, a baseband modulated signal may be approximated by a sinusoidal continuous wave signal with a frequency f < sub > m </ sub >.

The DoD is required by law to " maintain a Standard Positioning Service ( as defined in the federal radio navigation plan and the standard positioning service signal specification ) that will be available on a continuous, worldwide basis ," and " develop measures to prevent hostile use of GPS and its augmentations without unduly disrupting or degrading civilian uses.

Message-signalled interrupts behave very much like edge-triggered interrupts, in that the interrupt is a momentary signal rather than a continuous condition.

This is because LCD pixels open to allow a continuous stream of light to pass through until instructed by the video signal to produce a darker color ( see also ghosting ).

* A resel is a resolution element, used to describe the discrete number of resolvable elements of a continuous signal ( e. g. in optical imaging ).

This insertion is possible because the spectrum of the monochrome TV signal is not continuous ( for most typical video content ), hence empty space exists which can be utilized.

The term now applies to any signal that can be measured or decomposed along a continuous variable such as energy in electron spectroscopy or mass to charge ratio in mass spectrometry.

Such samples have a continuous Fourier spectrum that uniformly spreads its amplitude thereby reducing the measured signal intensity, as is observed in SAXS.

Sampling is the process of converting a signal ( for example, a function of continuous time or space ) into a numeric sequence ( a function of discrete time or space ).

Some amputees experience continuous pain that varies in intensity or quality ; others experience several bouts a day, or it may occur only once every week or two.

By contrast, non-digital ( or analog ) systems use a continuous range of values to represent information and in these systems the exact informational size of 1 Bd varies.

Since this force varies with the position of the charge and by Coloumb's Law it is defined at all points in space, is a continuous function of the charge's position ( x, y, z ).

Stream ciphers encrypt paintext digits one at a time on a continuous stream of data and the transformation of successive digits varies during the encryption process.

The frequency of mouth ulcers varies from fewer than 4 episodes per year ( 85 % of all cases ) to more than one episode per month ( 10 % of all cases ) including people suffering from continuous recurrent aphthous stomatitis ( RAS ).

This example shows that the kernel and cokernel of elliptic operators can jump discontinuously as the elliptic operator varies, so there is no nice formula for their dimensions in terms of continuous topological data.

So, people adopt continuous optimisation strategies, where they assume that the variable varies continuously over the domain.

In this system the transmitted signal of a known stable frequency continuous wave varies up and down in frequency over a fixed period of time by a modulating signal.

One, if he / she has been missing from his / her home or usual residence for seven years ( the period varies from state to state ); or such absence has been continuous without explanation, or when those persons most likely to hear from him / her have heard nothing ; and the missing person cannot be located by inquiry and by diligent search.

certainly the awakened alarm over the comic books and the continuous concern over prurient literature indicate some peripheral aspects of this influence.

Despite continuous wars or imperial expansion on the Empire's frontiers and one year-long civil war over the imperial succession, the Mediterranean world remained at peace for more than two centuries.

If X and Y are Banach spaces over the same ground field K, the set of all continuous K-linear maps T: X → Y is denoted by B ( X, Y ).

Thus, body forces are specified by vector fields which are assumed to be continuous over the entire volume of the body, i. e. acting on every point in it.

If a simply stable system response neither decays nor grows over time, and has no oscillations, it is marginally stable: in this case the system transfer function has non-repeated poles at complex plane origin ( i. e. their real and complex component is zero in the continuous time case ).

Such inputs are often created by sampling a continuous function, such as the amplitude of a person's voice over time.

The practical measurement of traffic is typically based on continuous observations over several days or weeks, during which the instantaneous traffic is recorded at regular, short intervals ( such as every few seconds ).

The film comprises a continuous narrative over seven scenes, rendered in a total of nine shots.

From 1896 there was continuous litigation in the United States over the patents covering the basic mechanisms that made motion pictures possible.

St Albans is Hertfordshire's oldest town, a modern city shaped by over 2000 years of continuous human occupation.

In addition, the firm is known for the attention it gives to cost control, operational details and continuous product development, allowing it to lower its prices by an average of two to three percent over the decade to 2010, while continuing its global expansion.

Through the fundamental theorem of calculus, which they independently developed, integration is connected with differentiation: if f is a continuous real-valued function defined on a closed interval, then, once an antiderivative F of f is known, the definite integral of f over that interval is given by

A laser can be classified as operating in either continuous or pulsed mode, depending on whether the power output is essentially continuous over time or whether its output takes the form of pulses of light on one or another time scale.

When the modulation rate is on time scales much slower than the cavity lifetime and the time period over which energy can be stored in the lasing medium or pumping mechanism, then it is still classified as a " modulated " or " pulsed " continuous wave laser.

In most cases these lasers are still termed " continuous wave " as their output power is steady when averaged over any longer time periods, with the very high frequency power variations having little or no impact in the intended application.

Many innovations and technical refinements have been made in printing processes and presses over the years, including the development of presses with multiple units ( each containing one printing plate ) that can print multi-color images in one pass on both sides of the sheet, and presses that accommodate continuous rolls ( webs ) of paper, known as web presses.

Morocco is a fairly stable economy with continuous growth over the past half-century.

While the supergravity description assumes a continuous space-time, Matrix theory predicts that, at short distances, non-commutative geometry takes over, somewhat similar to the way the continuum of water breaks down at short distances in favor of the graininess of molecules.

Each new form, also, as soon as it has been improved, will be able to spread over the open and continuous area, and will thus come into competition with many other forms ... the new forms produced on large areas, which have already been victorious over many competitors, will be those that will spread most widely, and will give rise to the greatest number of new varieties and species.

A random variable can be " mixed ", with part of its probability spread out over an interval like a typical continuous variable, and part of it concentrated on particular values like a discrete variable.

The new house features a set of automatically operated blinds that prevent it overheating when the sun is too hot for the plants together with a system that blows a continuous stream of cool air over the plants.

Historical remark: In its original form by F. Riesz ( 1909 ) the theorem states that every continuous linear functional A over the space C ( 1 ) of continuous functions in the interval can be represented in the form