Basics of a Diplexer
As the name suggests, a diplexer is a device that takes two signals (frequencies) and allows both frequencies to be passed through on one port at the same time. For instance, if there is one frequency at 800mhz and another at 300mhz, both the high and low frequencies are passed to the diplexer and then passed through the same line, such as a coaxial cable, at the same time.
Diplexer as a Passive Device
The diplexer, although able to accomplish a rather complex task, is actually nothing more than a passive device, meaning it only grabs frequencies as they are passed through to the device, and it does not actively seek out signals. Simply put, the diplexer doesn't realize the difference between and input and an output; rather, it simply passes the frequencies along its line in tandem.
Diplexer Use Examples
One example of a diplexer in action occurs when a satellite TV customer is receiving his satellite signal for cable shows and his over-the-air signal for local channels over an antenna. The signals are both being sent to the customer's television set at the same time over one coaxial cable hooked up to the television set top box; however, both signals are carried on the same cable at different frequencies to avoid any disruption. A more commercial use is the radio antenna atop the Empire State Building in New York, which transmits dozens of radio signals over a four-panel unit, thanks to diplexer technology.
Tags: passed through, same time, coaxial cable, frequencies passed