2 phase equalization – Comtech EF Data PCB-4300 User Manual
Page 38
PCB-4300 1:2 Phase Combiner
Revision 2
Operation and Adjustment Procedures MN/PCB4300.IOM
3–8
5
(cont)
Offline
SSPA
‘FRC=’
Setting
AOF Value
Measured Output Level (dBm)
@Fre=__________
1
23 AOF#1=_____________ #1=________________
2
13 AOF#2=_____________ #2=________________
3
12 AOF#3=_____________ #3=________________
6
If necessary, fine-tune the offsets of one or more of the SSPAs to achieve
equalization. Record the final offsets and output levels in the above table. (The offsets
are adjusted by the serial remote command
address; Y=1, 2, or 3 – individual SSPA offset in question; and Z.ZZ=desired offset
level).
For example, if it is desired to set the offset level of AOF#3 to 3.75 dB, and the PCB-
4300 address is 1, then serial remote command <1/AOF=3,3.75 should be sent.
3.4.2 Phase Equalization
Once the amplitudes have been equalized at the selected frequency, the phase paths can be
aligned. This is accomplished by adjusting the two phase shifters inside the PCB-4300 box (see
Figure 3-4), using the Phase Shifter Adjustment Tool Kit, such that the Combined Output Power
Level is maximized and the “Wasted” Output Power Level is minimized.
Referring to the block diagram in Figure 1-2, there are two phase shifters:
• The phase shifter in the path to SSPA#1 are used to equalize the phase between SSPAs
#1 and #2;
• The phase shifter in the path to SSPA#3 is used to equalize the phase between SSPAs #3
and #2.
Since they were equalized to a “reference” (i.e., #2),by default SSPAs #1 and #3 will be equalized
to each other.
Figure 3-4. Phase Shifter Adjustment Locations