Rohde & Schwarz R&S UPP, Руководство пользователя

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Instrument Functions
R&S
®
UPP
405 User Manual 1411.1055.32 ─ 10
Only two filters are offered for the R&S UPP.
The user-definable filters are configured as filters 01 to 09 in the filter panel (see Chap-
ter 5.40, "User-Definable Filters" , on page 469) and can then be used (repeatedly if
necessary) in the analyzer.
For more information on the available weighting filters, see Chapter 5.41, "Weighting
Filters" , on page 478.
Note: Regardless of the digital filters selected here, a further input filter ("prefilter") can
be looped into the test channel. Moreover, the analog bandwidth can be restricted with
the aid of the "Bandwidth" parameter field, which corresponds to an additional lowpass
filter.
Remote command:
SENSe[1]:FILTer<n2>
on page 773
For a description of the filters and their setting parameters, see Chapter 5.39.4, "Filter
Table" , on page 468.
Equalizer
Used for activating/deactivating a precorrector table for the FFT bins.
In this way, the frequency response of a transmission link can be precorrected, for
example, and in so doing the measurement point is transformed into another reference
point.
When precorrection is enabled the computed FFT bins are multiplied by a frequency-
dependent factor after which they are used to calculate the nth octave bands and
applied to the display.
The factor is determined by interpolation between the two adjacent frequency refer-
ence points in the precorrector table.
Precorrection of the FFT spectrum is an attractive alternative to filtering the input sig-
nal, since the precorrector file can simply be generated from the frequency response
requiring precorrection and need not be in the form of a coefficient file or pole/zero file.
Application:
In acoustic measurements (e.g. with mobile telephones) on artificial ears of type 3.2 or
higher, it is possible to compensate for the transfer function ERP (ear reference point)
to DRP (drum reference point). Measurement of the sound waves by the microphone
applied to the "eardrum" can thus be referred to the required measurement point (at
the auricle).
Frequency Band Analysis