Global Microwave Systems Inc. M2T-D3 Manual De Usuario
100-M0113X1 Rev. 04-17-09 PAGE 9 OF 41
4.0 Theory of Operation
The Messenger 2 Transmitter (M2T) accepts Standard Definition (SD) or High Definition
(HD) 4:2:2 digital video or analog SD video and analog stereo audio inputs (Mic or Line
level). The video is compressed according to the Advanced Video Compression (AVC)
/h.264 specifications. The low-latency AVC Encoder supports the Baseline Profiles with
resolutions from 480 to 1080 with support for either interlaced or progressive formats.
The audio is compressed using MPEG layer II compression. Low rate user data up to
38.4K Baud can be optionally supported. The audio, video and user data packets PES
streams are multiplexed with basic service data to indicate the service name. The
stream can be scrambled with AES scrambling system to provide protection in sensitive
applications.
A complete GMS Messenger 2 Camera Link for wireless camera application includes
the Messenger 2 Transmitter, the Messenger Smart Receiver (MSR), a SD/HD AVC
Decoder and one or several external Block Down – Converters (BDC), as shown in the
Figure 1 below. The M2T provides professional Audio/Video (A/V) interfaces and
processing. All versions of the Messenger Digital Link family use a robust digital
modulation system known as Coded Orthogonal Frequency Division Multiplexed (C-
OFDM) that provides frequency diversity and powerful Forward Error Correction (FEC)
algorithms.
The Messenger Smart Receiver (MSR) provides for Spatial Pre-Detect Maximal-Ratio
Diversity Combining of up to six independent antennas per MSR to increase the Signal
Strength, Signal-to-Noise Ratio and combat short delay spread multipath reflections
found in indoor environments. There is a dramatic increase in the operating threshold
when multiple high-gain antennas and Block Down-Converters (BDC) are used with the
MSR, greatly enhancing link robustness when operating at the high data rates as
required for HD transmission. The MDR outputs a transport stream simultaneously over
ASI and SPI interfaces. External Audio/Video/Data MPEG Decoders are sold
separately that support HD or SD AVC Decoding.
The 4K HIGH-THROUGHPUT OPTION enables user-selectable options to set
bandwidths from 6 MHz to 16 MHz and to double the throughput of our standard M2T
(Up to 63 Mbps!). Using 4K carriers and the 16 MHz bandwidth, the link can support HD
operation with > 12 Mbps while running QPSK and ½ FEC. This increases link
robustness and provides an additional 13.5 dB increase in link margin (>4.7 x increase
in operating range!) for the same throughput rate in a standard HD MPEG-2 DVB-T
system! With the HIGH-THROUGHPUT OPTION you can run with fully DVB-T
compliant 2K carriers and bandwidths of 6, 7, or 8 MHz. When switched to 4K carriers
user can select 12, 14 or 16 MHz bandwidth.
The 4K HIGH-THROUGHPUT OPTION is also useful when transmitting multiple video
streams through one transmitter. This option requires a special receiver configuration.
Please contact GMS Sales for additional information.
(HD) 4:2:2 digital video or analog SD video and analog stereo audio inputs (Mic or Line
level). The video is compressed according to the Advanced Video Compression (AVC)
/h.264 specifications. The low-latency AVC Encoder supports the Baseline Profiles with
resolutions from 480 to 1080 with support for either interlaced or progressive formats.
The audio is compressed using MPEG layer II compression. Low rate user data up to
38.4K Baud can be optionally supported. The audio, video and user data packets PES
streams are multiplexed with basic service data to indicate the service name. The
stream can be scrambled with AES scrambling system to provide protection in sensitive
applications.
A complete GMS Messenger 2 Camera Link for wireless camera application includes
the Messenger 2 Transmitter, the Messenger Smart Receiver (MSR), a SD/HD AVC
Decoder and one or several external Block Down – Converters (BDC), as shown in the
Figure 1 below. The M2T provides professional Audio/Video (A/V) interfaces and
processing. All versions of the Messenger Digital Link family use a robust digital
modulation system known as Coded Orthogonal Frequency Division Multiplexed (C-
OFDM) that provides frequency diversity and powerful Forward Error Correction (FEC)
algorithms.
The Messenger Smart Receiver (MSR) provides for Spatial Pre-Detect Maximal-Ratio
Diversity Combining of up to six independent antennas per MSR to increase the Signal
Strength, Signal-to-Noise Ratio and combat short delay spread multipath reflections
found in indoor environments. There is a dramatic increase in the operating threshold
when multiple high-gain antennas and Block Down-Converters (BDC) are used with the
MSR, greatly enhancing link robustness when operating at the high data rates as
required for HD transmission. The MDR outputs a transport stream simultaneously over
ASI and SPI interfaces. External Audio/Video/Data MPEG Decoders are sold
separately that support HD or SD AVC Decoding.
The 4K HIGH-THROUGHPUT OPTION enables user-selectable options to set
bandwidths from 6 MHz to 16 MHz and to double the throughput of our standard M2T
(Up to 63 Mbps!). Using 4K carriers and the 16 MHz bandwidth, the link can support HD
operation with > 12 Mbps while running QPSK and ½ FEC. This increases link
robustness and provides an additional 13.5 dB increase in link margin (>4.7 x increase
in operating range!) for the same throughput rate in a standard HD MPEG-2 DVB-T
system! With the HIGH-THROUGHPUT OPTION you can run with fully DVB-T
compliant 2K carriers and bandwidths of 6, 7, or 8 MHz. When switched to 4K carriers
user can select 12, 14 or 16 MHz bandwidth.
The 4K HIGH-THROUGHPUT OPTION is also useful when transmitting multiple video
streams through one transmitter. This option requires a special receiver configuration.
Please contact GMS Sales for additional information.