ÿþ<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <link rel="stylesheet" type="text/css" href="../../Nor150_style_sheet.css" /> <title>Noise selfnoise inherent</title> </head> <body> <h1>Specifications</h1> <p> Self-noise levels<br /> The self-noise is measured with the calibration set to  26.0 dB corresponding to a microphone sensitivity of 50 mV/Pa. For voltage input, the level 0 dB then corresponds to 1¼V. Typical values for the self-noise are 5dB lower than the values stated. The noise levels are measured without light in the display.<br /><br /> Noise measured with 18 pF microphone dummy and microphone preamplifier Nor1209, averaged over 30 s of measurement time:<br /> Spectral weighting functions:<br /> A-weighted: 13 dB<br /> C-weighted: 15 dB<br /> Z-normal -weighted: 25 dB<br /> Z-wide -weighted: 45 dB<br /> Filter bands:<br /> 1/3 oct: 0,4 Hz to 5,0 Hz:45 dB<br /> 1/3 oct: 6.3 Hz to 250 Hz: 10 dB<br /> 1/3 oct: 315 Hz to 20 kHz: 5 dB<br /><br /> Noise measured with Nor1225 microphone and preamplifier Nor1209, averaged over 30 s of measurement time:<br /> Spectral weighting functions:<br /> A-weighted: 18 dB<br /> C-weighted: 22 dB<br /> Z-normal -weighted: 30 dB<br /> Z-wide -weighted: 50 dB<br /> Filter bands:<br /> 1/3 oct: 0,4 Hz to 5,0 Hz: 45 dB<br /> 1/3 oct: 6.3 Hz to 250 Hz: 15 dB<br /> 1/3 oct: 315 Hz to 20 kHz: 10 dB<br /><br /> Noise measured with the input terminal on the sound level meter short-circuited to ground, averaged over 30 s of measurement time:<br /> Spectral weighting functions:<br /> A-weighted: 10 dB<br /> C-weighted: 10 dB<br /> Z-normal -weighted: 15 dB<br /> Z-wide -weighted: 15 dB<br /> Filter bands:<br /> 1/3 oct: 0,4 Hz to 5,0 Hz: 0 dB<br /> 1/3 oct: 6.3 Hz to 250 Hz: 0 dB<br /> 1/3 oct: 315 Hz to 20 kHz: 7 dB<br /> </p> </body> </html>