123:, they are far more susceptible to noise and offset voltage-related problems as these errors may become multiplied. When dealing with high-frequency signals, phase-related problems may be quite complex. For this reason, manufacturing wide-range general-purpose analog multipliers is far more difficult than ordinary operational amplifiers, and such devices are typically produced using specialist technologies and
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techniques. At low frequencies, a digital solution is cheaper and more effective and allows the circuit function to be modified in firmware. As frequencies rise, the cost of implementing digital solutions increases much more steeply than for analog solutions. As digital technology advances, the use
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in order to digitize the input signal allowing RMS and a whole range of other functions to be carried out by a digital processor. However, blindly digitizing the signal as early in the signal path as possible costs unreasonable amounts of power due to the need for high-speed ADCs. A much more
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A four-quadrant multiplier is one where inputs and outputs may swing positive and negative. Many multipliers only work in 2 quadrants (one input may only have one polarity), or single quadrant (inputs and outputs have only one polarity, usually all positive).
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designed to be used as a volume control may have a signal input designed for 1 Vp-p, and a control input designed for 0-5 V dc; that is, the two inputs are not symmetrical and the control input will have a limited bandwidth.
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If one input of an analog multiplier is held at a steady-state voltage, a signal at the second input will be scaled in proportion to the level on the fixed input. In this case, the analog multiplier may be considered to be a
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are now destined to become digitized sooner or later in the signal path, and if at all possible the functions that would require a multiplier tend to be moved to the digital side. For example, in early
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171:, true RMS functions were provided by external analog multiplier circuits. Nowadays (with the exception of high-frequency measurements) the tendency is to increase the sampling rate of the
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efficient solution involves analog preprocessing to condition the signal and reduce its bandwidth so that energy is spent to digitize only the bandwidth that contains useful information.
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analog multiplier, the two signal inputs have identical characteristics. Applications specific to a true analog multiplier are those where both inputs are signals, for example in a
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An electronic analog multiplier can be called by several names, depending on the function it is used to serve (see analog multiplier applications).
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of analog multipliers tends to be ever more marginalized towards higher-frequency circuits or very specialized applications.
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to implement many functions such as tone control and AGC without having to process the digitized signal directly.
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and produces an output which is their product. Such circuits can be used to implement related functions such as
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In most cases, the functions performed by an analog multiplier may be performed better and at lower cost using
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is a circuit whose output current is a 4 quadrant multiplication of its two differential inputs.
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Integrated circuits analog multipliers are incorporated into many applications, such as a
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Some commonly available Analog
Multiplier ICs in the market are MPY634 from
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Although analog multiplier circuits are very similar to
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Analog multiplication can be accomplished by using the
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By contrast, in what is generally considered to be a
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Voltage-controlled amplifier versus analog multiplier
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150:Analog versus digital tradeoff in multiplication
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146:and many more from other IC manufacturers.
350:"Multiple-input four-quadrant multiplier"
34:(apply same signal to both inputs), and
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265:(especially voltage-controlled filters)
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74:or an analog circuit to implement a
320:. ON Semiconductor. Archived from
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315:"Linear Four-Quadrant Multiplier"
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114:Linear Four Quadrant Multiplier
269:PAM-pulse amplitude modulation
191:Analog multiplier applications
181:digitally controlled resistors
138:, AD534, AD632 and AD734 from
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52:voltage controlled amplifier
26:is a device that takes two
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283:Analog Dialogue, June 2013
281:Multipliers vs. Modulators
129:instrumentation amplifiers
112:are available such as the
76:discrete Fourier transform
156:digital signal processing
86:Analog multiplier devices
248:Analog signal processing
213:Variable-gain amplifier
253:Automatic gain control
121:operational amplifiers
56:automatic gain control
338:Analog Devices AD834
169:digital multimeters
258:True RMS converter
205:Electronics portal
162:In addition, most
106:true RMS converter
60:integrated circuit
136:Texas Instruments
24:analog multiplier
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233:Companding
288:See also
144:Intersil
238:Squelch
164:signals
32:squares
183:allow
325:(PDF)
318:(PDF)
294:NE612
22:, an
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