Analog signal processing

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Analog signal processing refers to the form of signal processing that is carried out on analog signals and by the use of analog means. The concepts established in analog electronics are used in order to implement the mathematical algorithms that process the analog signals. Mathematical values are represented as a continuous physical quantity such as voltage levels, electric current values or electric charge. Small errors or noise that may interfere with such physical quantities can result in corresponding errors in the representation of signals related to these physical quantities.

Analog signal processing vs DSPs

There are capabilities which are present in analog signal processing which are absent in digital signal processing, though the latter is often considered to be far more powerful and cheaper. If the original data to be processed is in the analog form, it is expensive and complicated to use devices such as an ADC (analog-to-digital converter) and a DAC (digital-to-analog converter).

These devices are required in order to carry out the conversion of signals from their analog form to the digital form for processing by a digital signal processor (DSP) and back to the analog form for the user to interpret. Instead of deploying such means, it is recommendable to use an analog signal processor. In addition to the added overall complexity of the system, the digital propagation delay that may accompany the processing may reach levels unacceptable for a high-speed system.

Greater levels of efficiency can be achieved by processing analog signals, even if the output data required has to be in digital form. This benefit is manifest in the measurement of alternating current power. In the case of a complex, reactive load, it may become necessary to over-sample the voltage and current signals in order to measure power. An analog multiplier, which is driven by the voltage and current in the load, results in an output that is proportional to the instantaneous power. An integrated and sampled output can be obtained from the output.

Applications of analog signal processing

Analog signal processing is used in a number of engineering applications. Analog signal processors are used when the signal manipulation has to be carried out in a simple manner, unlike other complicated methods. Analog multipliers and dividers provide easy gain control and are useful in applications like continuous power measurement. They are used in ratiometric functions and have a considerably high accuracy rate of the order of 1%.