Acrodyne NW8201E DIGITAL TELEVISION BROADCAST TRANSMITTER User Manual 32 NV8202 26 04 06 01 00

Acrodyne Industries, Inc. DIGITAL TELEVISION BROADCAST TRANSMITTER 32 NV8202 26 04 06 01 00

Users Manual Part 7

Chapter 2 Design and Characteristics2099.9595.72 - 2.18 - E-21.5.2 AmplifierFig. 22 AmplifierThe air-cooled, broadband VM8350A1 amplifier operates in the range from 170 MHz to254 MHz (VHF band III). It can be used both for analog and digital signals without re-quiring any adjustments. The output power of an amplifier is 325 W in the case of digital TV.The amplifiers amplify the exciter signals distributed by the splitter and forward them to thecombiner. The amplifiers in a transmitter rack are controlled via the rack controller. Mea-sured values and status information are recorded by the rack controller via CAN bus andforwarded to the NETCCU® transmitter control unit. The number of exciters in the transmit-ter depends on the transmit power. Note For detailed information about the amplifier, refer to the amplifier manual.
Chapter 2 Design and Characteristics2099.9595.72 - 2.19 - E-21.5.3 CombinerFig. 23 Combiner (1) with splitter (2)The RF power output by the amplifiers is merged via the combiner.The combiner consists of a cascade of 3 dB couplers housed in a single unit.
Chapter 2 Design and Characteristics2099.9595.72 - 2.20 - E-21.5.4 AbsorberFig. 24 AbsorberThe absorber functions as the absorber resistor for the combiner. If combiner operation isnot symmetrical (e.g. one or more amplifiers are disconnected or removed), the portion ofthe RF power that cannot be coupled in is expelled as additional thermal energy via thetransmitter's exhaust system.

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