Tektronix 2200 Manual Do Utilizador

3-5

A crosspoint bus consists of a group of switches called crosspoints, 
each with a different video or key input. The row of switches has 
a common output called a bus. 

The various crosspoint buses on the switcher’s control panel 
make up the Source Select Subpanel (the large matrix of buttons 
that occupies the left 1/3 of the control panel), which is used for 
connecting the video and key input buses to the crosspoint output 
buses that feed transition and effects circuits.

The pushbuttons at the intersections between the input buses and 
the output buses are called crosspoint buttons

Crosspoint buses include the following:

■

A and B background buses and the Key buses on the M/Es

■

PGM (Program) and PST (Preset) background buses and the 
DSK (Downstream Keyer) bus on the PGM-PST/DSK section

■

PVW (Preview)/Mask/Aux (auxiliary) buses

The background buses feed the video mixers, allowing you to 
select background sources and do transitions between them. The 
key buses feed the keyers, allowing you to set up keys which are 
also fed to the mixers for keying over the background. Lastly, the 
aux buses select signals and send them directly to switcher 
outputs for feeding external devices such as digital picture 
manipulators; this makes the same inputs that are available to the 
switcher also available to the external devices.