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Page 9of 51 DVT2000-001
SECTION 1
GENERAL INFORMATION
1.1 INTRODUCTION
This manual describes the installation and operation of Wegener Communications DVT2000
Digital Video Transmitter. The transmitter is a rack-mounted unit, as shown in Figure 1. It is
normally used in conjunction with the DVR2000 receiver in satellite-based digital video
broadcast networks to transmit and receive video, audio and data.
1.2 SYSTEM DESCRIPTION
The DVT2000 Transmitter and DVR2000 Receiver comprise the DV2000 Digital Video
Transmission System. The system uses the MPEG-2 compression technique, with I, B and P
frames. At the transmit site (uplink), the DVT2000 transmitter converts analog or digital video
and audio signals to compressed digital form and transmits them over a satellite link to the
receivers. The high level of compression permits many video signals to be transmitted in the
space normally occupied by a single video signal.
At the receive site, a dish antenna with an LNB (low-noise block downconverter) recovers the
signal and converts it to the L-band frequency range (950 to 2050 MHz). This L-band signal is
carried by coaxial cable (possibly through in-line amplifiers) to the integrated DVR2000
receiver/decoder. The receiver automatically tunes to the desired signal and reconstructs the
original video and audio signals.
1.2.1 System Capabilities
The system features user-defined flexibility. Video compression can be varied between 2.5Mb/s
for low-end applications, to 15 Mb/s for sports and entertainment events. Full field/frame
compensation is possible, with variable B frames and GOP size. The system handles both NTSC
and PAL video, and analog or digital audio.
A variable rate QPSK modem with convolutional and Reed-Solomon error correction permits
users to define the optimal combination of transmission rate up to 20 Mb/s.
1.2.2 Transmitter Characteristics
The DVT2000 Digital Video Transmitter accepts analog video in composite format in NTSC or
PAL standards. The video is converted to CCIR 601 (D1) digital video for subsequent
processing. The unit also accepts D1 video directly.
The encoded multiplexed data is Forward Error Correction (FEC) coded using DVB compliant
concatenated coding. This signal is then modulated by a variable rate Quadrature Phase-Shift
Keyed (QPSK) modulator and output as a 70 MHz IF, tunable in 100 kHz steps. The transmitter