What is the difference between digital and analog signals?

Answer 1

Digital/Analog An analog or analog signal is any time continuous signal where some time varying feature of the signal is a representation of some other time varying quantity. It differs from a digital signal in that small fluctuations in the signal are meaningful. Analog is usually thought of in an electrical context, however mechanical, pneumatic, hydraulic, and other systems may also convey analog signals.

An analog signal uses some property of the medium to convey the signal's information. For example, an aneroid barometer uses rotary position as the signal to convey pressure information. Electrically, the property most commonly used is voltage followed closely by frequency, current, and charge.

Any information may be conveyed by an analog signal, often such a signal is a measured response to changes in physical phenomena, such as sound, light, temperature, position, or pressure, and is achieved using a transducer.

For example, in sound recording, fluctuations in air pressure (that is to say, sound) strike the diaphragm of a microphone which causes corresponding fluctuations in a voltage or the current in an electric circuit. The voltage or the current is said to be an "analog" of the sound.

Since an analog signal has a theoretically infinite resolution, it will always have a higher resolution than any digital system where the resolution is in discrete steps. In practice, as analog systems become more complex, effects such as nonlinearity and noise ultimately degrade analog resolution such that digital systems surpass it. In analog systems, it is difficult to detect when such degradation occurs, but in digital systems, degradation can not only be detected but corrected as well.

Disadvantage

The primary disadvantage of analog signaling is that any system has noise - i.e., random variation. As the signal is copied and re-copied, or transmitted over long distances, these random variations become dominant. Electrically, these losses can be diminished by shielding, good connections, and several cable types such as coaxial or twisted pair.

The effects of noise make signal loss and distortion impossible to recover, since amplifying the signal to recover attenuated parts of the signal amplifies the noise as well. Even if the resolution of an analog signal is higher than a comparable digital signal, in many cases, the difference is overshadowed by the noise in the signal

Digital

The term digital signal is used to refer to more than one concept. It can refer to discrete-time signals that are digitized, or to the waveform signals in a digital system. Digital signals are digital representations of discrete-time signals, which are often derived from analog signals.

An analog signal is a datum that changes over time-say, the temperature at a given location; the depth of a certain point in a pond; or the amplitude of the voltage at some node in a circuit that can be represented as a mathematical function, with time as the free variable (abscissa) and the signal itself as the dependent variable (ordinate). A discrete-time signal is a sampled version of an analog signal: the value of the datum is noted at fixed intervals (for example, every microsecond) rather than continuously.

If individual time values of the discrete-time signal, instead of being measured precisely (which would require an infinite number of digits), are approximated to a certain precision-which, therefore, only requires a specific number of digits-then the resultant data stream is termed a digital signal. The process of approximating the precise value within a fixed number of digits, or bits, is called quantization.

In conceptual summary, a digital signal is a quantized discrete-time signal; a discrete-time signal is a sampled analog signal.

In the Digital Revolution, the usage of digital signals has increased significantly. Many modern media devices, especially the ones that connect with computers use digital signals to represent signals that were traditionally represented as continuous-time signals; cell phones, music and video players, personal video recorders, and digital cameras are examples.

In most applications, digital signals are represented as binary numbers, so their precision of quantization is measured in bits. Suppose, for example, that we wish to measure a signal to two significant decimal digits. Since seven bits, or binary digits, can record 128 discrete values (viz., from 0 to 127), those seven bits are more than sufficient to express a range of one hundred values.

Summary: Digital communication systems offer much more efficiency, better performance, and much greater the flexibility.

Analog in a watch is where you have to read the numbers. Digital shows the numbers for you.

a digital signal is what a computer system is based around; mainly zeros and ones / or noughts and ones as illustrated.

a zero equates to zero volts approx .

a one ( logic ) is 5 volts +_ a tolerance value.

but there is limited range of signal in between these 2 points.

a measured value of 2.5 volts would not be equal to either a logic 1 or nought .

....

when a circuit / usually a transistor device switches on or off the voltage at its terminal usually changes from zero to 5 volts or logic 1 .

the digital circuit only recognizes values at or around these 2 points and interprets them as a logic 1 or 0.

..

in the case of the analog signal, the value could change between a negative value to positive or from zero to a positive value, within the supply constraints and

still be recognized.

Answer 2

it is rael say

Answer 3

An analog signal changes value continuously.

A digital signal changes in discrete steps.
Analog in a watch is where you have to read the numbers. Digtal shows the numbers for you.

Answer 4

A digital signal has just two states, either true or false - or, as in machine language, either 1 or 0 - that are transmitted as two different defined entities. Depending on the system, the entities could either be two different but fixed amplitude levels or two different but fixed signal frequencies.

An analog signal varies in a way that, depending on the system is strictly related to either amplitude changes - as in the AM (Amplitude Modulation) system - or to frequency changes - as in the FM (Frequencey Modulation) system. In either case the instantaneous values of the signal can have any value between fixed limits.

Answer 5

A Signal that can take any value between the two extremes of high and low is an Analogue signal. E.g. any alternating current or voltage signal.

in a Digital system the signal is not allowed to have a value(s) beyond the predefined. Normally there are only two values allowed. they could be any arbitrary values as per the system but normally chacterised as 0 and 1. Forming a what is called the binary system.

Answer 6

• digital signals use codes to represent values and changes of values are abrupt and discontinuous.
• analog signals use analogy to represent values and changes of values are smooth and continuous.

Answer 7

analogue signals are curved and digital signals are staright

Answer 8

The analogue signal are waves which are directly reproduced by the receiver. The digital signal needs a computer based device as the receiver because it is composed from data.

Answer 9

An analog system uses continuously varying analog signals for transmission of data. A digital system on the other hand uses discrete digital signals.

Answer 10

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