Isolation and Signal Distribution

by Pat Brown

A common task in Audio Land is the need to feed a number of inputs from a single signal source. This may include driving a rack of amplifiers, providing feeds to the press, or distributing a signal around a building or campus. The methods used to accomplish this range from the profoundly simple to quite complex, and the appropriate method must be determined after sizing up the situation.

To Match or Not to Match

Impedance matching means that an output is terminated with a “mirror” input impedance. This configuration yields maximum power transfer, and more importantly reduces reflections from a load back to the source. In multimedia systems, the matched interface is used for very high frequency signals. These include video, antenna and digital interfaces. One drawback of the matched interface is that active or passive splitters must be used if the source must drive multiple inputs.

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