Comtech-ef-data PCB-4000 Manual do Utilizador descarregar pdf (Página 35)

PCB-4000 1+1 Phase Combiner Revision 2

Installation, Startup, and Troubleshooting Procedures MN/PCB4000.IOM

3–7

3.4 Gain or Amplitude Balance Verification and Alignment



ThisprocedureisgenerallynotnecessaryifallparametersofSection3.3have

beenmet.



As a result of the configuration of the waveguide switches in a 1+1 system, it is possible to

measuretheindividualgainofeachSSPApathbyswitchingeachSSPAindividuallytotheoutput

load.



Thisprocedu

reassumesthattheoutputportisterminatedandthatdatawillbetakenusingthe

CombinedOutputPowerandWastedPowerTestCouplers(

Figure 3-1).



Followthesesteps:



Step Task

A. Attach a power meter to the Combined Output Power Test Coupler (Figure 3-1).

B. Apply a low-level signal at center frequency, making sure the output signal will be at least 10 dB below

Prated.

To measure only the individual gain of SSPA#1, SSPA#2 must by bypassed by changing the state of the

waveguide switches via remote control (for detailed remote command and query information, see Chapter

5. SERIAL REMOTE CONTROL):

A. Execute remote command RED=0;

B. Execute remote command BYP=2.

The output of SSPA#1 will be sent to the system output, while SSPA#2 will be muted and directed to the

“wasted” port.

3 Record the amplitude or gain level of SSPA#1.

Execute remote command BYP=1 to measure the individual gain of SSPA#2. This time, the output of

SSPA#2 will be sent to the system output, while SSPA#1 will be muted and directed to the “wasted” port.

5 Record the amplitude or gain level of SSPA#2.

Compare the levels of the two paths. Typically, the gains of each SSPA will be within ± 1 dB at center

frequency. If the above test is performed at other frequencies, it is reasonable to assume that the gain

difference may be greater.

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Comtech-ef-data PCB-4000 Manual do Utilizador Página 35