In practice an analog signal is subject to electronic noise and distortion introduced by communication channels and signal processing operations, which can progressively degrade the signal-to-noise ratio.

Therefore as analog signal processing systems become more complex, they may ultimately degrade signal resolution to such an extent that their performance is surpassed by digital systems.

* Analog signal processing

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

Audio signal processing, sometimes referred to as audio processing, is the intentional alteration of auditory signals, or sound, often through an audio effect or effects unit.

As audio signals may be electronically represented in either digital or analog format, signal processing may occur in either domain.

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

Since that time, as computers and software became more advanced, digital signal processing has become the method of choice.

This permits signal processing using digital circuits such as microprocessors and computers.

Although such a conversion can be prone to loss, most modern audio systems use this approach as the techniques of digital signal processing are much more powerful and efficient than analog domain signal processing.

Here a musical signal is tuned to the correct pitch using digital signal processing techniques.

It is often used in signal processing for analyzing functions or series of values, such as time domain signals.

* In signal processing, autocorrelation can give information about repeating events like musical beats ( for example, to determine tempo ) or pulsar frequencies, though it cannot tell the position in time of the beat.

Signal processing would be applied to determine the direction of maximum illumination and so develop a signal to steer the antenna toward the target.

Bandwidth in hertz is a central concept in many fields, including electronics, information theory, digital communications, radio communications, signal processing, and spectroscopy.

In many signal processing contexts, bandwidth is a valuable and limited resource.

The main advantage is the fine definition of the analog signal which has the potential for an infinite amount of signal resolution.

Based on this definition, the drain efficiency cannot exceed 25 % for a class A amplifier that is supplied drain bias current through resistors ( because RF signal has its zero level at about 50 % of the input DC ).

Digital video was first introduced commercially in 1986 with the Sony D-1 format, which recorded an uncompressed standard definition component video signal in digital form instead of the high-band analog forms that had been commonplace until then.

The widespread adoption of digital video has also drastically reduced the bandwidth needed for a high-definition video signal ( with HDV and AVCHD, as well as several commercial variants such as DVCPRO-HD, all using less bandwidth than a standard definition analog signal ) and tapeless camcorders based on flash memory and often a variant of MPEG-4.

Class AB is widely considered a good compromise for audio amplifiers, since much of the time the music is quiet enough that the signal stays in the " class A " region, where it is amplified with good fidelity, and by definition if passing out of this region, is large enough that the distortion products typical of class B are relatively small.

According to one definition of digital signal, the modulated signal is a digital signal, and according to another definition, the modulation is a form of digital-to-analog conversion.

The effects of receiving delayed and distorted versions of the signal can be seen in the loss of definition of the signal transitions.

The definition used by some authors defines phase noise to be the power spectral density ( PSD ) of a signal's phase, while the other definition is based on the PSD of the signal itself.

An alternative definition of SNR is as the reciprocal of the coefficient of variation, i. e., the ratio of mean to standard deviation of a signal or measurement:

If the signal data are not constant, then can be calculated from data where the signal is zero or relatively constant .</ ref > Notice that such an alternative definition is only useful for variables that are always non-negative ( such as photon counts and luminance ).

Yet another alternative, very specific and distinct definition of SNR is employed to characterize sensitivity of imaging systems ; see signal to noise ratio ( imaging ).

According to the most common definition of digital signal, both baseband and passband signals representing bit-streams are considered as digital transmission, while an alternative definition only considers the baseband signal as digital, and passband transmission of digital data as a form of digital-to-analog conversion.

But during nighttime hours the skywave radiations are reflected from the ionosphere, thereby creating the possibility of one station's rendering service, via skywave, at a much greater distance than it can through its groundwave signal, and at the same time vastly complicating the interference problem because of the still greater distance over which these skywave signals may cause interference to the signals of stations on the same and closely adjacent frequencies.

The design of a mechanical interlocking frame is much like a mechanical puzzle, but once understood, the principles can be applied to any track and signal arrangement.

This instrument provides an electrical signal proportional to the angular deviations of the platform and can be used to automatically hold the platform on true heading.

Since altruism takes away resources from the altruist it can be a " honest signal " of resource availability and the abilities needed to gather resources.

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.

Converting an analog signal to digital form introduces a constant low-level noise called quantization noise into the signal which determines the noise floor, but once in digital form the signal can in general be processed or transmitted without introducing additional noise or distortion.

Even if the resolution of an analog signal is higher than a comparable digital signal, the difference can be overshadowed by the noise in the signal.

For reception, a local oscillator will typically restore the suppressed carrier so the signal can be demodulated with a product detector.

The Amiga chipset can genlock: adjust its own screen refresh timing to match an NTSC or PAL video signal.

Raymond Williams argues that there is no unique and or individual aesthetic object which can be extrapolated from the art world, but that there is a continuum of cultural forms and experience of which ordinary speech and experiences may signal as art.

The analog television signal contains timing and synchronization information so that the receiver can reconstruct a two-dimensional moving image from a one-dimensional time-varying signal.

This noise can be avoided by modulation of the signal at a higher frequency, for example through the use of a lock-in amplifier.

In telecommunications, asynchronous communication is transmission of data without the use of an external clock signal, where data can be transmitted intermittently rather than in a steady stream .< ref >

Autocorrelation of the signal can be analyzed in terms of the diffusion of the particles.

The fact that in equivalent baseband models of communication systems, the signal spectrum consists of both negative and positive frequencies, can lead to confusion about bandwidth, since they are sometimes referred to only by the positive half, and one will occasionally see expressions such as, where is the total bandwidth ( i. e. the maximum passband bandwidth of the carrier-modulated RF signal and the minimum passband bandwidth of the physical passband channel ), and is the positive bandwidth ( the baseband bandwidth of the equivalent channel model ).