The DISTRIBUTION cards are used to buffer the GAC output signals. A Set of these cards are connected together with the distribution-backplane to form the ECL DISTRIBUTION Cage, which produces multiple copies of the buffered GAC output. The input to these Distribution cards, come from the BUFFER cards located in the GAC cage. The outputs will go to the backend instruments, like the Pulsar Machine, etc. The input and output signals are in ECL differential form. The MC10116 ICs are used as the ECL differential buffers.
The DISTRIBUTION Card PCB design is nade in such a way, that the same card can be configured ( by changing the input / output connectors ) either as a Receiver Card ( Rx ) or Transmitter Card ( Tx ).
The JP1 connector ( 50-pin Berg ) of the Rx card receive the ECL Differential signals from the GAC Buffer card, then the signals flow through the MC10116 ICs to reach the 96-pin EURO connector JP2, which sends the signals to the backplane. in the Rx card, MC10116 IC inputs have te termination resistor ( 110ω ) and the outputs are tied to VEE through 470ω resistor packs. The backplane distributes the signal to one or more Tx cards. Now the signals enter the Tx card's input connector JP1 ( 96-pin EURO ) connector, the signals enter the MC10116 ICs, and the IC outputs go to the Tx cards output connector JP2 ( 50-pin Berg connector). Now the signals are avilable for distribution to the backplane instruments. Since the backplane provides the common termination for the differential signals ( 110ω SMD resistors across the line ), none of the Tx cards have the input termination resistors, although a provision is available at the MC10116 IC inputs. Also in the Tx cards, all the outputs of the MC10116 ICs are tied to VEE through teh 470ω resister packs before they are sent to the output connector.