Rohde & Schwarz CMU 200 - Fig. 4-45 Multitone Configuration - Filter

CMU Audio Generator and Analyzer (Option CMU-B41)
1100.4903.12 4.95 E-10
The audio receive path of the CMU may contain the following filter stages:
AF Path Coupling Capacitor stage to block the DC component of the AF input signal including a possible DC
offset of the input amplifier. With DC coupling, the complete AF input signal is measured.
Weighting Weighting filter according to CCITT or C-message weighted filter.
Band Pass Audio band pass filter with selectable bandwidth to limit the input frequencies to a definite
audio band and eliminate unwanted signal components. The allowed bandwidth depends on
the AF Path Coupling.
The audio results are generated at the end of the audio receive path, after the audio signal has passed all filter
stages that are switched on.
Fig. 4-45 Multitone Configuration – Filter
Default All Set-
tings
The Default All Settings switch assigns default values to all fields in the Filter tab
(the default values are quoted in the command description in chapter 6 of this man-
ual). Two additional default switches reset all AF Channel One or all AF Channel
Two settings, respectively.
Remote control
DEFault:MULTitone:FILTer ON | OFF
DEFault:MULTitone:AFxChannel:FILTer ON | OFF (x = 1,2)
AF Channel One
The table section AF Channel One defines the input path for the Multitone meas-
urement. The following settings are provided:
Band pass Selection of the bandwidth of the CMU's audio band pass. A
separate band pass can be selected for AC coupling and DC
coupling.
Weighting Use of a C-message weighted filter (C-Message), a CCITT
weighting filter or none of these filters (OFF).
The CMU provides a broad selection of bandwidths with lower cutoff frequencies
between 0 Hz and 300 Hz and upper cutoff frequencies between 250 Hz and
21 kHz (see command description in Chapter 6).
Note: If the AF Path Coupling is set to DC (see section Measurement Control
(Multitone Configuration – Control) on page 4.89), the audio analyzer
receives the complete AF input signal including a possible DC compo-
nent. To avoid measurement inaccuracies, a band pass with a lower
cutoff
≥ 6 Hz must be used.