General Description
R&S
®
CMW-B400B/-B405A
17
User Manual 1176.8116.02 ─ 04
You can use this filter stage to eliminate a possible DC component in the audio sig-
nal that may cause measurement inaccuracies.
●
Weighting filter
The human ear is a nonlinear sensor. Its sensitivity depends on the frequency.
Weighting filters take this into account by deemphasizing very low and very high
frequency components to which the human ear is less sensitive.
Several weighting filters with different shape have been standardized. The follow-
ing filters are supported:
–
A-weighting filter defined in IEC 61672. The A-weighted scale is commonly
used in local ordinances and standards.
–
CCITT weighting filter defined in ITU-T Rec. O.41 (also known as ITU-T P53
filter). This filter is used for international telephone circuits.
–
C-message weighting filter defined in IEEE 743. This filter is used for North
American telephone circuits.
●
Bandpass filter with configurable center frequency and bandwidth. This filter can
not be disabled and is only relevant for the single tone measurement result "Band-
pass Level".
The following figure provides an overview of the filter positions in the input path and of
the measurement points for the individual results. The lowpass, highpass and weight-
ing filter can be disabled separately.
Fig. 3-5: Input path filters and results
3.4 Measurement Results
All results of an audio measurement are displayed in a single tab. There is one tab for
analog measurements and one tab for digital measurements.
For scenarios that do not involve an audio measurement, the tabs are hidden (for
example external speech analysis).
The following sections describe the results for the individual signal types.
................................................................................................18
Measurement Results
深圳德标仪器
135-1095-0799
