Example 2.1.9, it can be seen that This network is sometimes called a two-way splitter the insertion loss is slightly reduced but this has been because it splits the signal from a single input port into carried out at the expense of system match. The manu- two output ports. The circuit has been designed for low facturer is fully aware of this but relies on the fact that insertion loss and it does this by trading off proper the reflected signal will be weak and that it will not se- matching against insertion loss. riously affect signal quality. The manufacturer also hopes that the cable system will be correctly matched by the antenna and that any reflections set up at the receiver end Example 2.1.9 will be absorbed by the hopefully matched antenna ter- Figure 2.1-25 shows a commercially available 75 S mination to the cable system. This design is popular be- matching network. Calculate: (a) the ratio Vout/Voc when cause the installation cost of an additional resistor is all ports are each terminated with 75 S, (b) the input saved by the manufacturer. impedance to the matching network when the output ports are each terminated with 75 O and (c) the source 2.1.7.4 Amplified antenna distribution impedance to either receiver when the remaining ports systems are each terminated in 75 Q. Given: 75 S network splitter of Figure 2.1-25 with Amplified aerial distribution systems are aerial distribu- 75 S terminations. tion systems which incorporate amplifiers to compensate Required: (a) Ratio Vout/Voc, (b) input impedance of for signal transmission, distribution and matching losses. matching network, (c) source impedance to either Two systems will be discussed here. The first concerns receiver. a relatively simple distribution system where indoor amplifiers are used. The second system deals with a more elaborate system using amplifiers mounted on the aerial (masthead amplifiers) to compensate for distribution and matching losses. 75 S2 Matching network 2.1.7.5 Amplified aerial distribution systems using amplifiers Antenna Out