8
July 6, 2010
AN1559.0
measurement of interest is S21 in order to optimize the
MTV aggressor cancellation. Once the “MTV Optimization
Setup (Static Coupling Channel)” is ready, use the
software provided to configure the device as previously
described.
1. Select the MTV frequency band of operation.
2. Start with the lowest gain setting.
3. Then adjust the I and Q (or gain and phase) until the
maximum attenuation is achieved at the desired
frequency.
Figure 8 is an example of the type of cancellation that
should be achieved when the I and Q values have been
optimized.
Once the cancellation has been optimized, record the I
and Q values for the optimization of the setup used.
FIGURE 7. MTV OPTIMIZATION SETUP DIAGRAM
ATTENUATOR PAD
TO SET COUPLING LOSS
MTV AGGRESSOR
NETWORK
ANALYZER
QHx220
CANCELLATION
NODE
POWER
SPLITTER
PORT 1
PORT 2
50
Ω
TERMINATION
POWER
SPLITTER
PATH
FIGURE 8. EXAMPLE OF OPTIMUM CANCELLATION (MTV)
-35
-30
-25
-20
-15
-10
-5
0
400
420
440
460
480
500
520
540
560
580
600
FREQUENCY (MHz)
AFTER CANCELLATION
BEFORE CANCELLATION
Application Note 1559
