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Analogue Electronics refers to electronics systems with analogue signals with any continuously variable signal. It differs from digital electronics in that small fluctuations in the signal are meaningful in that they are continuously variable rather than digitally quantised.
Origin of term
The word "analogue" implies an analogy between cause and effect, voltage in and voltage out, current in and current out, sound in and sound out. An analog circuit (or analogue circuit) is therefore an electric circuit that operates on analog signals.
Explanation
Analogue electronics is sometimes confused with other sub-divisions of the general field of Electronics which include Power electronics and Digital electronics.
Analogs
The word "analogue" implies an analogy between cause and effect, voltage in and voltage out, current in and current out, sound in and sound out. For example, in an analogue sound recording, the variation in pressure of a sound striking a microphone creates a corresponding variation in the current passing through it or votage across it. An increase in the volume or amplitude of the sound causes the fluctuation of the current or voltage to increase proportionally while keeping the same waveform or shape and electrical analogue. Clocks with hands are often called analogue displays; those that display digits are usually called digital displays. However, many analogue clocks are actually digital since the hands do not move in a smooth continuous motion, but in small steps every second or sub division of a second.
In the field of Power Electronics analogs can be the Energy Storing variables such as the current in an Inductor or the Voltage across the terminals of a Capacitor.
Information and analogue signals
Any information may be conveyed by an analogue 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. An analogue 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.
Another method of conveying an analogue signal is to use modulation. In this, some base signal (e.g., a sinusoidal carrier wave) has one of its properties altered: amplitude modulation involves altering the amplitude of a sinusoidal voltage waveform by the source information, frequency modulation changes the frequency. Other techniques, such as changing the phase of the base signal do also work.
Analogue circuits do not involve quantisation of information into digital format. The source signal information being measured over the circuit, whether sound, light, pressure, temperature, or an exceeded limit, remains continuous from end to end. See digital for a discussion of digital vs. analogue.
Disadvantages of analog systems
The primary disadvantage of analogue signalling is that any system has noise, that is random disturbances or variations in it. As the signal is copied and re-copied, or transmitted over long distances, these random variations become dominant and lead to signal degradation. Electrically these losses are lessened by shielding, good connections, and several cable types such as coax and twisted pair and using low noise amplifiers. The effects of random noise can make signal loss and distortion impossible to recover, since amplifying the signal to recover attenuated parts of the signal often generates more noise and amplifies the noise as well.
Sources: Some of an earlier version of this article was originally taken from Federal Standard 1037C in support of MIL-STD-188.
Analog operations
While operating on an analog signal, an analog circuit changes the signal in some manner or manners. It may be designed to amplify, attenuate, provide isolation, distort, or modify the signal in some other way. It can be used to convert the signal into some other format such as a digital signal. Analog circuits also modify signals in unintended ways such as adding noise or distortion.
Analogue Electronics is frequently confused with other sub-divisions of the general field of Electronics which include Power electronics and Digital electronics.Or in the field of Power Electronics can be the Energy Storing variables such as the current in an Inductor or the Voltage across the terminals of a Capacitor. Any information may be conveyed by an analogue 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.
Analogue signals
An analogue 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.
For example, in an analogue sound recording, the variation in pressure of a sound striking a microphone creates a corresponding variation in the current passing through it or votage across it. An increase in the volume or amplitude of the sound causes the fluctuation of the current or voltage to increase proportionally while keeping the same waveform or shape and electrical analogue.
Disadvantages of analog systems
The primary disadvantage of analogue signalling is that any system has noise, that is random disturbances or variations in it. As the signal is copied and re-copied, or transmitted over long distances, these random variations become dominant and lead to signal degradation. Electrically these losses are lessened by shielding, good connections, and several cable types such as coax and twisted pair and using low noise amplifiers. See digital circuit for a discussion of digital vs. analogue.
Noise
The effects of random noise can make signal loss and distortion impossible to recover, since amplifying the signal to recover attenuated parts of the signal often generates more noise and amplifies the noise as well.
Another method of conveying an analogue signal is to use modulation. In this, some base signal (e.g., a sinusoidal carrier wave) has one of its properties altered: amplitude modulation involves altering the amplitude of a sinusoidal voltage waveform by the source information, frequency modulation changes the frequency. Other techniques, such as changing the phase of the base signal do also work.
Analogue circuits do not involve quantisation of information into digital format. The source signal information being measured over the circuit, whether sound, light, pressure, temperature, or an exceeded limit, remains continuous from end to end.
Clocks with hands are often called analogue displays; those that display digits are usually called digital displays. However, many analogue clocks are actually digital since the hands do not move in a smooth continuous motion, but in small steps every second or sub division of a second.
Passive versus active
Passive analog circuits consume no external electrical power while active analog circuits use an electrical power source to achieve the designer's goals. An example of a passive analog circuit is a passive filter that limits the amplitude at some frequencies vs. others. A similar example of an active analog circuit is an active filter. It does a similar job only it uses an amplifier to accomplish a similar task.
Advantages of a passive analog circuit are it requires no power source, gives off less heat, and may produce less noise. Advantages of an active analog circuit is it can load the signal less, amplify as well as attenuate the signal and by using capacitors in combination with amplifiers it can simulate an inductor. Simulation of inductions has the advantage of reducing weight and cost.
Analog integrated circuit
Main article: Analog chipActive or passive analog electronic circuits can be fabricated directly onto semiconductor substrates, such as silicon. Such circuits are called analog integrated circuits. They may occur as sub-systems of other digital systems (e.g., an analog comparator in a microcontroller.) Analog integrated circuit design is a highly specialized area.
Analogue circuit functions
- Analog multipliers
- electronic amplifiers
- electronic filters
- electronic oscillators
- Phase-locked loops
- electronic mixers
- Power conversion
- Electronic Power Supply
- impedance matchers
- operational amplifiers
- comparators
- Voltage regulators