ADCP-61-814 ∙ Issue 1 ∙ April 1999

2.2.4Rear Interface Units

The RIU, mounted in the rear of the chassis, provides the interface for the coaxial cable and the jack access card which is plugged into the RIU from the front of the chassis. The interface connectors accept coaxial cable terminated with F or BNC connectors. See Figure 9. The RIU is factory wired with ± 5 V and ground for powering the jack access card when it is plugged into the RIU. The ± 5 V is passed to the jack access card through pins while the ground is connected through the RIU and card bodies.

REAR

INTERFACE

UNIT

JACK

ACCESS

CARD

FROM VIDEO

TRANSPORT

SYSTEM

TO VIDEO

MODULATOR

Figure 9. RIU and Jack Access Card

6772-C

2.2.5AVIS Jack Access and Amplifier Cards

There are three basic card circuit configurations available:

•A passive (–20dB) card with Monitor, IN and OUT little coax jacks for full jack access.

•An active (0 dB baseband video) card with Monitor, IN and OUT little coax jacks for full jack access.

•Active (0, +10 and +20 dB gain amplifier) cards without access jacks.

PWR-AVIS Cards, except for the 0,10 and 20 dB active (amplifier) cards, provide the means to access circuits for monitoring and maintenance functions or to amplify an incoming signal. See Figure 10. The monitor network circuitry for the active and passive cards provides access to the signal at 0 or -20 dB level respectively. The active card provides a 0 dB unity gain signal with respect to the output signal. The active amplifier cards provide fixed gain of 0, 10 and 20 dB respectively and are for return path application with bandwidth of 5 MHz to 200 MHz. Power (± 5

V)and ground for active cards is automatically transferred from the RIU when the card is plugged in. The cards with jack circuitry automatically provide 75-ohm circuit termination.

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© 1999, ADC Telecommunications, Inc.