Portable spectrum analyzer Arinst SSA-TG R2 6 April 2019
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16
Note. When changing the external attenuator, perform the normalization operation again.
Attention!
If the input signal level is greatly exceeded, a warning message
Dynamic range exceeded
appears on the screen of the device. In this case, the input level cannot be displayed correctly. In this
case, it is necessary to increase the level of signal attenuation by external attenuators.
Attention! The use of small values of the input attenuator requires special attention, since a
signal exceeding 10 dBm can damage the input circuit of the device!
7.6.7. To exit the menu of setting the frequency and output power of the generator, press the button
(14)
«MENU».
7.7. Setting parameters and measuring the reflection coefficient S11
Our device ARINST SSA-TG R2, in the measurement mode of the S11 parameter, uses a scalar SOL
calibration.
And these measurements are not vector, that is, they provide compensation only for the amplitude of
the signal without phase.
The scalar calibration algorithm is as follows S11
corr
= (S11
open
+ S11
short
) / 2;
S11 = S11
measure
- S11
corr
.
In this case, the minimum level of the measured coefficient S11 is set by the calibration S11
load
.
that is, S11
min
= S11
load
- S11
corr
;
Screenshots presented by you confirm this.
7.7.1. To measure the reflection coefficient, it is necessary to select the
S11
mode (Figure 18).
igure 18 Turning on S11 mode
Note. The reflection coefficient S11 will be displayed in a logarithmic grid with vertical axis in dB. The
horizontal axis displays the specified frequency range of the signal.
7.7.2. Set the desired level of attenuation of the input attenuator
Input Atten
, in the range from 0 to
-
30 dB. Setting the parameter is performed by “scrolling” the values to the fixed selected area.
Attention! The use of small values of the input attenuator requires special attention, since a
signal exceeding 10 dBm can damage the input circuit of the device!
Note. Use external attenuators if necessary.
7.7.3. Depending on the equipment to which the generator output signal is applied, set the signal
power value in the range from -15 to -25 dBm. Setting the
parameter is performed by “scrolling” the val-
ues to a fixed selected area.
Note. To measure the reflection coefficient
S11
, it is necessary to use a directional coupler or measur-
ing bridge at the appropriate frequency range (not included in the package). In our example in figure 19,
