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8. Waveform Recording function
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Outline
When the Waveform Recording program NX-42WR is installed, this function enables users to record a
sound pressure waveform on SD card as a WAVE file of PCM form, together with the stored numerical
data. The recorded WAVE files can be played on computer and can be used for frequency analysis.
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Outline of the waveform recording function
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Recording mode
There are two recording modes: event mode and total mode.
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Event mode
The event mode can only be used when Auto store (Auto or Timer Auto) is selected.
Three types of recording are available:
(1) Manual recording
The sound pressure waveform of arbitrary, user defined time is recorded during Auto store.
(2) Level recording
The sound pressure waveform is recorded only when the input signal is higher than the preset
level.
(3) Interval recording
The sound pressure waveform is recorded at a pre-set fixed interval (10min / 1h).
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Total mode
(4) Total recording
In Auto store mode, the sound pressure waveform is continuously recorded during the
measurement. In Manual store mode, the sound waveform is recorded during the entire
measurement and stored after finishing the measurement.
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Sampling frequency
The sampling frequency can be chosen from 48 kHz, 24 kHz, and 12 kHz, depending on the maximum
sound frequency which you want to analyze. When you want to record in high-quality sound, set to a high
sampling frequency. When you do not need a high sound quality, or you want to record for a long time,
set to a low sampling frequency.
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Bit length
The recording bit length can be selected from 16 bits and 24 bits. Increased accuracy of analysis and
better sound quality can be obtained as the bit length value increases.
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Approximate recording times for SD memory cards
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Data apply for Auto store, bit length 16bit,
L
p
store interval 100ms.
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The duration of recording with 24bit
becomes shorter than that with 16bit.
