Tektronix ECO422D, Instruction Manual, Page: 90 / 128

Performance Verification
5- 18
ECO422D SD/HD Changeover Unit Instruction Manual
13. Serial Digital Audio Check for Channel 1 Primary
Switch between 2 and 4 dB down from nominal
Connect the equipment as shown in Figure 5--4.
AG7
ECO422D
Serial Audio 3+4
Serial Audio 1+2
Step Attenuator
75
Ω
termination
Figure 5- 4: Setup to check the serial audio levels
Set the Channel Configuration switches to Disabled (signal not checked) for
all channels (set all the DIP switches on S1 through S11 to “open”).
Set the Channel Configuration switch to Serial Digital Audio for Channel 1
(set S1--5 to “closed,” S1--1 through S1--4 “open,” and S1--6 through S1--8
“open”).
Set the step attenuator to 0 dB of attenuation.
Set the TG700 AG7 to output either a 1000 or 800 Hz serial digital audio
tone on channels 1+2 and 3+4.
Press Reset.
CHECK -- that there are no errors shown for either the Primary or Backup
ECO422D sync sources.
Set the ECO422D to “Primary” Sync Source and Auto Switch to “Switch on
Fault.”
Add attenuation, 0.5 dB at a time, to the Primary input signal until the signal
source switches to Backup.
Serial Digital Audio
Checks