Audio level meter using LM3915

Posted on Feb 7, 2014

An analog VU meter is often included in the audio equipment to display signal levels in volume units. Analog VU meters with peak LED Another Thumbnail magnetoelectric VU meter response of a VU meter (black line) compared with the instantaneous input level (gray areas) of a drum beat. Level in dB and the time in seconds VU electric meterIt is inte

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ntionally a slow measurement, the average of peaks and valleys of short duration to reflect the material considered loudness. It was originally developed in 1939 by a joint effort of Bell Labs and Broadcaster CBS and NBC to measure and standardize the level of the phone line. The instrument used to measure the volume of VU-called indicator (VI) instrument. Most users ignore this and call it a VU meter. The following is a schematic drawing: VU typical scale is from -20 to +3. The rise and fall times of both 300 meters milliseconds, which means that if a constant sine wave of amplitude 0 VU is applied suddenly, the 300 meters will take milliseconds to reach 0 on a scale. Behaves as a full-wave instrument on average, and not optimal to measure the peak level.

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