Tektronix RSA2200A, User Manual

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Trigger
3- 96
RSA2203A & RSA2208A User Manual
IF Trigger
This section describes the IF trigger function, which operates when the trigger
source is set to Level (Full BW). The IF trigger function monitors the level of
signals that pass through the IF filter and generates a trigger when the level
exceeds the threshold.
When IF trigger is selected, the trigger level can be set in the range of 1 to 100%.
The full scale of the internal A/D converter is considered as 100%. This is
almost equivalent to the set value of reference level. For example, if the
reference level is set to +3 dBm, 3 dBm becomes the full scale of the A/D
converter. If the trigger level is set to 100%, a trigger will occur when a signal
with a level higher than 3 dBm is applied.
The Figure 3--72 shows the relationship between trigger level set values and
signal power that causes a trigger to be generated when the reference level is
+3 dBm and the input signal is a single sine wave. If the trigger level is set to
50%, the amplitude of --6 dB from the reference level corresponds to the signal
power that causes a trigger. That is:
+3 dBm (reference level) -- 6 dB = --3 dBm
5
0
--5
--10
--15
--20
--25
--30
--35
--40
0 10 20 30 40 50 60 70 80 90 100
Trigger level (%)
Amplitude
(dB)
Figure 3- 72: Trigger level vs. Amplitude (reference level = +3 dBm)
Setting a Trigger Level