Tektronix ECO 422, Инструкция по эксплуатации

Страница: 82 / 177

Performance Verification
5–18
ECO 422
CHECK – that the Primary signal still shows an error and automatically
switches back to Backup. If the ECO 422 does not continue to show the
Primary signal in error after the reset, continue adding attenuation until the
Primary signal switches to Backup again.
Note the attenuation of the step attenuator.
CHECK – that the ECO switches between 2 and 4 dB down.
14. Serial Digital Audio Check for Channel 1 Backup
Switch between 2 and 4 dB down from nominal
Connect the equipment as shown in Figure except swap the Primary and
Backup cables so that the attenuator is on the Backup side.
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 SPG 422 to output either a 1000 or 800 Hz serial digital audio tone
on all four channels.
Press Reset.
CHECK – that there are no errors shown for either the Primary or Backup
ECO 422 sync sources.
Set the ECO 422 to “Backup” Sync Source and Auto Switch to “Switch on
Fault.”
Add attenuation, 0.5 dB at a time, to the Backup input signal until the signal
source switches to Primary.
Press the Reset button on the front panel and try to return the signal source
to Backup.
CHECK – that the Backup signal still shows an error and automatically
switches back to Primary. If the ECO 422 does not continue to show the
Backup signal in error after the reset, continue adding attenuation until the
Backup signal switches to Primary again.
Note the attenuation of the step attenuator.
CHECK – that the ECO switches between 2 and 4 dB down.