ERI: A Higher-Power Analog/IBOC Diplexer
Following the launch of the 788 Series All-Pass Diplexer in the spring, Electronics Research Inc. this fall showed a higher-power version of this high-level diplexer, capable of 49 kW analog and 7 kW digital input power.
The 788 Series combines analog and digital (HD Radio) with greater efficiency and better performance than other techniques, the company states.
“The All-Pass Diplexer system does not have the high insertion loss of 10 dB hybrid injectors, which waste significant amounts of analog and digital transmitter power. The All Pass analog insertion loss is –0.35 dB or less and the digital loss is –1.4 dB or less.”
Also, ERI says that group delay performance is superior to alternative high-level combining methods and is correctable by currently available FM transmitters. It says group delay of the analog signal is less than 350 nanoseconds and the digital delay is less than 600 nanoseconds.
The All-Pass Diplexer gives FM radio stations that are operating a –20 dBc IBOC power level with a 10 dB hybrid injector the opportunity to increase digital power without having to invest in a new transmitter.
The base model is convection cooling, 3-1/8 inch 50 ohm analog input (22 kW), 1-5/8 inch 50 ohm digital input (3 kW). The “A” version is forced air cooling, 3-1/8 inch 50 ohm analog input (36 kW), 1-5/8 inch 50 ohm digital input (5 kW). The “B” model is forced air cooling, 6-1/8 inch 50 ohm analog input (49 kW), 3-1/8 inch 50 ohm digital input (7 kW).
For system planning, a loss calculator is available.