Tektronix ECO422D Technical Reference page 16

Preface
SPG600/300 Sync Pulse
Generators
xii
When operated in the switch-on-fault mode, the ECO422D will automatically
select the backup sync source should any of the primary inputs fail. However, in
the unlikely event both sync sources are faulty, the ECO422D will not alternate
between the two sources. If necessary, this function may be overridden with the
manual sync source selection. Manual source selection also facilitates periodic
testing of the changeover function. Switching is by mechanical relay with all
channels switched simultaneously.
The Electrical Fast Switch function, available with Opt. ELSW, improves the
changeover switching speed between inputs, and replaces the mechanical relay on
channels 4-6. Using this type of switch minimizes disturbance when switching
between primary and backup inputs. With Option ELSW, channels 4-6 can accept
only a black-burst or tri-level sync signal.
Front-panel controls are provided for source selection, operating mode, resetting
the fault indicators, and for disabling the front-panel controls. LED indicators
are also provided. Indication of fault and unit on line is also available through
the remote connector.
The SPG600 and SPG300 Sync Pulse Generators provide synchronization and
test signals for both traditional analog and mixed digital and analog facilities, in
both NTSC/525 and PAL/625 environments. These products are ideal as a stable
master sync signal, which is critical in digital broadcast environments.
When these instruments are configured for Stay GenLock mode, a momentary loss
of synchronization at the genlock reference input will not cause a disturbance in
the test signal and black outputs of the unit. When the genlock signal is reapplied,
the SPG system will gradually reacquire lock. This will cause little disruption in
the outputs of the device and will not cause any noticeable glitches in the outputs
of the SPG.
The Genlock source can be NTSC/PAL Black Burst, NTSC/PAL Sync, or CW.
When using CW lock, the Genlock timing can be adjusted on all the NTSC or
PAL color frames.
Video Sync Pulse Generator and ECO422D SD/HD Changeover Unit System Integration