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What is the difference between digital and analog signals?
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.
Why is it necessary to digitize voice signals?
To minimize the distortion of analog signals during transmission Because digital lines transmit signals more efficiently across distances than analog lines Because many telephone networks are moving over to digital interfaces
How can Analog signal be digitized?
There are chips that will convert a analog to a digital form. It works on the principle of comparing the input to a reference voltage and outputting the bits [digital] as a value compared to the reference voltage. it can be 4,8,12, of digital data for a 12bits the LSB is 2.4mv.
Many network hubs incorporate repeaters or amplifiers to regenerate signals so that attenuation of the signal does not occur?
As a rule a hub does not contain a repeater. Amplifiers would be used in analog communication, not digital communication. Attenuation is a process that occurs all the time in networks; you would place a repeater in an area where the attenuation would cause the signal to degrade to the point where it wouldn't be usable. You would want the repeater to be placed before that point.
What interferes with remote control signals?
Other radio signals. They can be from many different sources. Walkie-talkies, TV remotes, etc. Pretty much anything the broadcasts has the potential to interfere if the broadcasting channel is close to the signal band of your RC.
What is digital signal?
There are many forms of digital signals PWM, PAM, and more Basically is a signal that carry information to be extracted to its original form.
Why is digital signal immune to noise?
Digital signals can gather information with noise because the information component is determined whether its presence or absence a data bit. Digital signals can processed by digital circuit components they are cheaper an easily to create in many components on a signal chip.
How many states do electrical circuits on an IC integrated circuit have?
Not possible to say without knowing much more. In analog circuits every signal has an infinite continuum of states. In digital circuits every signal usually has two states (some digital circuits have been built with three states), but there may be many many billions of these signals (e.g. 21,000,000,000 is an awful lot of states).
How to change digital signals to analog signals and again from analog to digital signals?
modem Measuring usually the voltage of the analog signal many times a second in binary number code generates a digital signal, and using a binary number code to control the voltage of an output results in a reproduced analog signal. That is what is done for stuff like digital television. A Modem (prior answer) is for when the analog signals are used to connect digital computers (like yours) together, usually over a long distance.
What uses a digital signal?
Many television stations have been using digital signals for at least 30 years. They turned them into analog signals at the antenna for broadcast. Now they are simply leaving them in their original form.
Why digital signals are better than analog signals?
according to my view, to deal with digital signal is more easy then that of analog. and it also stable so many of the semiconductor circuits run only on dc signals...... i think doubt is clear now....
Why digital signal is better than analog signal?
the digital code is binar. so if you get a signal it is absolut. analogue signals can be interfered or altered through interferation.
What does digital signal processing entail?
Digital signal processing involves manipulating signals using mathematical algorithms implemented on a digital platform. It includes tasks such as filtering, compression, modulation, and noise reduction to enhance the quality of signals. DSP is essential in various fields like telecommunications, audio processing, image processing, and control systems.
What is the best signal between analog and digital?
This is a difficult question to answer. Digital signals in television and audio are hailed as the "best" quality but there are many factors that affect the quality of both analog and digital signals. Digital signals are not prone to quality loss once they are in a digital form. The data that makes up the signal can normally be stored, transmitted and received without error so the quality will be identical from start to finish. Analog signals can suffer from interference and losses which increase with the length of transmission line and with every active process used as the signal is stored and delivered. Therefore, in terms of quality loss, digital is likely to be the better medium. Digital signals in video and audio are frequently compressed. Raw HD data needs a data rate of 1500 megabits per second but broadcasters frequently compress an HD signal to as little as 6 megabits per second. The compression process inevitably results in a loss of detail and a loss of quality. SD data rates are 270 megabits as an uncompressed signal but are compressed to as little as 1-2 megabits for broadcast. Again, the signal quality suffers. Analog signals are always broadcast as full bandwidth signals so they do not suffer from quality loss due to compression. The final judgment regarding the best signal must be based on the quality of image seen. Without doubt, digital signal processing can deliver quality that most analog signals can never achieve but in reality, that is not always the case. Highly compressed digital television signals can often show a variety of unpleasant effects such as jerky movement and large blocks of the image without detail. As broadcasters devote more bandwidth to digital signals, the quality will improve but the quality is dependent on sufficient bandwidth for each signal. There will be many differing opinions on this topic but it must always be accepted that "digital" does not automatically mean "better".
What is the history of digital television?
The time it took to change analog television signals to all digital took about 25 years. It started around 1986 and many television stations had converted over to digital signal by the year 2010. Persons who owned analog televisions had to either buy a new digital television or use a converter box to get a clear signal.
How come your vhf signal is gone?
In the United States, Congress has required that major TV stations broadcast only digital signals beginning on 14 June 2009. TV and radio broadcasting begin with analog signals and older televisions are capable of receiving only analog signals. If your TV is receiving over-the-air signals (not via cable or satellite dish) and it is not digital capable or equipped with a digital conversion box, it will seem as if your VHF and UHF television signals have gone away. A conversion box can be purchased in many stores for $40-$60 or so, and up to two government coupons per household are available to cover $40 of that.
Why does signal processing in digital mode?
You can process signals with many analog circuits. The advantage of Digital Signal Processing, is that once you have represented the signal in a digital form, you can use a computer program to perform much more complex operations on the signal than could be accomplished with an analog circuit. Such examples are noise cancellation and compression. With the recent advent of 'Digital TV', the stations can fit more information into a smaller 'bandwidth' through compression (much as you might ZIP a large file before emailing it), allowing for delivery of more content.
