Rohde & Schwarz EVSF1000, User Manual

Page: 82 / 295

Numeric Measurement Modes
R&S
®
EVSF1000
82 User Manual 1178.6410.02 ─ 05
In many avionics signals, channels are assigned to frequencies with a fixed offset. By
setting the step size of the rotary knob to the fixed offset, you can easily scroll through
the signal's channel frequencies using the rotary knob. Thus, for example, you can
analyze the measurement results for one channel after the other simply by changing
the selected channel frequency with the rotary knob.
The default step size for ILS/VOR mode is 50 kHz.
6.3.3.3 Ampt
Access VNC : [w]
The following settings define the amplification for the input signal.
RF Att ............................................................................................................................ 82
RF Mode ....................................................................................................................... 82
Transducer Correction ...................................................................................................83
RF Att
Determines how the attenuation of the RF signal is defined. The attenuation should be
adjusted such that the measured power level remains in the valid level range (indicated
by the green area of the bargraph, see
Chapter 6.1.3.1, "RF Level and Frequency Dis-
play" , on page 38). Note that the valid level range depends on the selected measure-
ment mode.
"Manual" The RF attenuation mode is specified manually (see "RF Mode"
on page 53).
"Auto" The RF attenuation mode is selected automatically.
The signal attenuation is selected automatically according to the sig-
nal strength.
This mode works best with clean signals. In difficult receiving condi-
tions, the "Low Noise", "Normal" or "Low Distortion" modes can be
more stable.
When monitoring signals with mostly constant signal levels, it is also
recommended that you use the "Low Noise", "Normal" or "Low Distor-
tion" mode.
If the R&S
EVSF1000 has to adapt the attenuation frequently, indica-
ted by a frequent clicking noise from the attenuator, spikes can occur
in the trace.
Remote command:
SETATTMODE
on page 183
SCOPE_ATTMODE
on page 260
FTT_ATTMODE
on page 257
IFSPECT_ATTMODE
on page 253
RF Mode
Defines the RF attenuation mode to be used.
"Low Noise" 15 dB pre-amplification
Provides a high sensitivity. Suitable when scanning the area for dis-
tant signals.
VOR Mode (Option R&S EVSG-K2)