B&K 2250 Light Instrukcja Użytkownika Pobierz pdf (Strona 103)

CHAPTER 10

1/1- and 1/3-octave Frequency Analysis (Optional Modules)

Spectrum Table shows the displayed part of the spectrum in tabular form – as in Fig.10.5.

Press the Table Format icon

at the top of the screen to select between two different

viewing formats:

– Two Parameters: for displaying values from both spectra

– One Parameter (wrap): for displaying values from the main spectrum only, but with

the columns wrapped on the display to allow as many values as possible on the screen

Fig.10.5

Spectrum table

To exit the Spectrum Table, tap .

Note: Save the template, if you want to use the display settings for other measurements.

Some parameters are calculated based on the spectra:

• SIL, PSIL, SIL3 and L

Xeq

(f1–f2) are calculated during the measurement and saved

together with the other measurement data

• The Noise Parameters NC, NR, RC, NCB, Loudness and Loudness Level are for display

only and calculated based on measured L

Xeq

spectra. This means that whenever you have a

Xeq

spectrum you can also calculate and display these parameters

• NC, NR, RC and NCB are defined for 1/1-octave L

Zeq

spectra, however, NC, NR, RC and

NCB are calculated for any frequency weighting and any octave bandwidth. A-, B- and

C-weighted spectra are converted to Z-weighted spectra and 1/3-octave spectra are

converted to 1/1-octave spectra before the calculation

• Loudness and Loudness Level are calculated for 1/3-octave spectra with any frequency

weighting. A-, B- and C-weighted spectra are converted to Z-weighted spectra before the

calculation

If 1/1-octave L

Zeq

spectra have been measured, then you can display a Noise Curve together

with the L

Zeq

spectrum, see example in Fig.10.6.

1 2 ... 98 99 100 101 102 103 104 105 106 107 108 ... 211 212

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B&K 2250 Light Instrukcja Użytkownika Strona 103