Norsonic nor1216, Instruction Manual

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10 Chapter 4
Technical description
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A C
Frequency [Hz] / Network
Level [dB]
Self-noise
The electrical noise when the microphone is substitut-
ed by an 20 pF capacitor is shown on the graph above.
0 dB corresponds to 1 µV. For a microphone with a
sensitivity of 50 mV/Pa (Nominal value of Nor1227 or
Nor1225), 0 dB voltage also corresponds to the normal
reference pressure for sound: 20 µPa and the noise
level may be compared with sound pressure level di-
rectly.
Typical self noise of the microphone system when the microphone is substituted by a capacitor with similar
capacitance as the microphone. Note that the acoustical self-noise for a real microphone will be higher due to
thermal noise in the microphone cartridge.