C-OFDM Digital Video

C-OFDM - Coded Orthogonal Frequency Division Multiplexed transmission technology provides a superior means of transmitting wireless information in high multipath environments. C-OFDM systems use 2000 coded carriers within the main signal, each carrier is coded modulated  for signal robustness. The loss of one or many coded carriers have no impact on the video received. Adjustable guard intervals minimize multipath interference. The system also uses Forward Error Correction coding, further increasing signal reliability. Multipathed signals are summed at the receiver, actually aiding in signal quality. C-OFDM systems have become the standard for transmission in Europe. C-OFDM transmitters involves three major components: A signal encoder, a modulator, and an RF transmitter. MPEG 2 is the industry standard for encoding an NTSC or PAL signal, the modulation scheme is C-OFDM.

• 99.99% Perfect Video Picture with Zero Color Shift

• Freedom of Movement Inside Buildings With Out Losing Video & Audio

• Upgrade Option Available to Transmit in HDTV

• License Free with Long Reaching Ranges

MSR Receiver

Applications:

• Wireless Audio/Video/Data Link Applications

• Electronic Tracking Antenna Systems

• Electronic News Gathering (ENG)

• Sports / Point of View

• Studio Wireless Links

• Helicopter links

• UAV/UGV Applications

• Mobile and Portable AV Applications

MSR Receiver

Key Features:

• Robust Link Performance with C-OFDM!

• Multi-Input Diversity Maximal-Ratio Combining!

• Provides superior coverage in the toughest reception areas!

• Enhanced Doppler performance for tracking moving vehicles!

• ASI output supports a wide variety of external decoders

• 49 MHz to 6 GHz (In-Bands) with Optional Internal or External Down-Converters

GMS Messenger Smart Receiver (MSR) System is a VHF/UHF DVB-T Receiver with several powerful and unique features. When used in conjunction with GMS Block Down Converters (BDCs), the MSR can cover frequency bands exceeding The first unique feature is Multiple-Input Maximal-Ratio Diversity Combining, up to six independent receive paths.

• Maximal-Ratio Diversity Combining can increase the Signal to Noise Ratio (SNR) by 2.5 dB or 78% for two inputs and 4 dB or 250% plus for 4 inputs or more if the antennas are getting the same signal from the transmitter. Providing significantly increased reception range!
   

• Using Space Diversity Combining the probability of good reception is dramatically increased!
   

• Possibility to increase transmitted bit rate and maintain the same robust link performance. This capability is especially helpful with broadcast quality links in studios and stadiums that require the use of the less robust 16 QAM or 64 QAM modulation modes to achieve the required video quality.

Unlike conventional DVB-T systems, the MSR is designed for mobile environments. With 2K carriers and 16-QAM, a dual-input or greater MSR can handle >570 Hz of Doppler frequency shift, which equates to 708 mph (1140 km/h) @ 504MHz carrier frequency. With 8K carriers and 16-QAM, a dual-input or greater MSR can handle >125 Hz of Doppler frequency shift, which equates to 155 mph (250 km/h) @ 500MHz carrier frequency. This feature is an enabling technology for C-OFDM based Helicopter and UAV links!

The MSR outputs a transport stream simultaneously over a dual output ASI and SPI parallel interfaces. External Audio/Video/Data Decoders are sold separately that support SD and HD MPEG-2 4:2:0 and/or 4:2:2, H.264, AVC and any other format that can be transmitted in a Transport Stream. LAN IP streaming interfaces are also available from GMS to support distribution of the Wireless Audio/Video/Data anywhere in the world via the World Wide WEB (WWW). This system architecture supports single or multiple programs by looping the ASI interface to multiple Decoders.

The MSR is normally used with GMS optional Block Down- Converters (BDCs) to provide frequency coverage from 862MHz to 6 GHz. GMS  BDCs can be mounted remotely, normally right at the antenna output (Optimizing system performance!) or within the MSR chassis as shown in the figure to the left. When remotely mounted, BDC power is provided via the IF coax cable. The MSR  MS Windows Control SW provides independent control of the power to each BDC.

A single MSR with internally mounted BDCs can support up to 4 independent antennas. With external BDCs each single MSR can support up to 6 independent antennas. The system automatically configures itself for inputs from 1 to 6. Both even and odd configurations are supported. Two additional card slots are provided for future options such as AES Decryption.

The MSR can provide autonomous acquisition, tracking and recovery. However, it was designed to be controlled via an IBM PC using its Window's- based control program. This program provides control of the center frequency, C-OFDM bandwidth, BDC power and the acquisition mode of the system. All other modulation parameters including spectral inversion are automatically detected and set during the acquisition process. Once locked onto the signal, the MSR Control SW provides an extensive array of status information.

The MSR is the heart of GMS  Messenger Smart Antenna (MSA) System, which combines multiple fixed antennas to form a reliable, cost-effective alternative to conventional electro-mechanical Dual-Axis or Single-Axis Auto-Tracking Antenna Systems. MSA provides auto-tracking over either a spherical pattern or a directional pattern of one or more DVB-T C-OFDM Audio/Video compliant transmissions with either 12 dB gain (pattern & gain is model dependent). The MSA system's high reliability is achieved because there are no moving parts! It is a fully electronic system, designed for harsh outdoor environments!

MPD Decoder

Key Features:

• Broadcast Quality 4:2:2 MPEG-2 Decoder

• Low Delay

• Compact Design

• Designed to mate with MSR

• Runs on 12VDC

The GMS Messenger Portable Decoder (MPD) is a compact professional 4:2:2 MPEG-2 digital audio/video decoder that is designed to be a companion to GMS  MSR Diversity Receiver. A mounting plate is provided that allows the MSR to be mounted on top of the MPD. Two fans in the MPD provide cooling for both the MPD and the MSR. The ASI output of the MSR is feed into the MPD, which receives the MPEG2 TS stream, decodes it and output signals via analog video/audio ports, SDI/AES ports. These units can be controlled via either the RS-232C or USB control ports. An optional 19-inch Rack-Mounted shelf is available that can mount up to two MPD/MSR in just 5.25" of rack space. Additionally, an optional in-line AC/DC power supply is available.

MSR Receiver

Number of Slots: 8

Number of Tuner/Demod Cards: Up to 6 (Slot 1 must contain a Tuner/Demod Card)
Slots 2-8 can be any combination of Tuner/Demod Cards and/or Block Down-Converter Cards

Interfaces

Control: RS-232C via DB9-F Connector or USB-1 via USB-B Connector

Transport Stream Out:  ASI (2 CH) via BNC-F Connector or SPI via 34 Pin Micro-Header, SAMTEC, ASP-114859-01Connector

DC Power: 2 pin, AMP 350786-2 Connector

AC Power: (Optional with external in-line cable assembly)

Controls & Status

Main Power: Front-Panel On/Off Control

BDC Power: Independent On/Off control via Windows Control SW

Front-Panel Status LEDs: "ACTIVE" - Provides indication of the health of the system and "LOCKED" -Provides indication that the TS output is valid

Full MSR System control and status is accessed through either its RS-232C or USB-1 control ports via the supplied MS Windows based control application.

A GMS remote control unit (RCU) is also available.

Physical

Dimensions: 8.55" (W) x 4.36" (D) x 4.0" (H)  or 21.7 cm x 11.07 cm x 10.16 cm

Weight: 32.07 oz (906 grams)

Environmental: Operational Temperature: -10 to 70 deg C

Humidity: Up to 100% non-condensing

DC Power

DC Voltage Range: 9 -15V

Power Consumption: 54 Watts (with 6 Tuner/Demods, powering 6 external BDCs)

Tuner/Demod Cards

Part Number: 710-A0619

Fully compliant with DVB-T ETS 300.744

COFDM RF Inputs

Number of Carriers: 2K or 8K

MSR Input Frequency: 49-862 MHz

User Control Input Frequency: translated to the input of the BDC's RF input band.

Frequency tuning resolution: 250 KHz

Frequency Acquisition and Recovery Range: +/- 350 KHz

Input Impedance: 75 Ohms

Noise Figure: Max: < 10 dB, Typical: <7 dB

System Frequency Accuracy: dependant on both MSR and BDC accuracy.

Bandwidth: Selectable 6,7,8MHz

Threshold**: For Dual inputs

 QPSK 1/2: <-93.5 dBm 

 16-QAM 1/2: <-87.5 dBm

 64-QAM 1/2: <-82.5 dBm

Modulation

Modulation Type: COFDM w/QPSK or 16-QAM or 64-QAM

FEC: 1/2, 2/3, 3/4

Guard Intervals: 1/32, 1/16,1/8,1/4

COFDM Carriers: 2k or 8k Carriers

MPD Decoder

Audio/Video Decoding

• Support ISO13818-1 TS demultiplexing (up to 32PID)

• Support ISO13818-2 (Main Profile @ Main Level and 422 Profile @ Main Level) video decoding

• Support ISO11172-3 and ISO13818-3 audio decoding, provide simultaneous 2 pairs of stereo (4 channels) decoding

• Support graphic display up to 16 bits/pel (OSD)

Transport Stream

Input
Type: DVB-ASI via BNC-F (Rear Panel)
Rate: 1 b/Sec to 213 Mb/Sec
TS Demultiplexing: In accordance with ISO13818-1 with up to 32 PIDs.

Output
Type: DVB-ASI loop via BNC-F (Rear Panel)
Rate: 1 b/Sec to 213 Mb/Sec

Video Decoding
Type: MPEG-2
Standard: Supports ISO13818-2
Profiles: Main Profile @ Main Level,
Simple Profile @ Main Level and 422 Profile @ Main Level
Decoding Rates: 4:2:2 P@ML(1.5-50MHz),  4:2:0 MP@ML(1.5-15MHz) and 4:2:0 SP@ML(1.5-15MHz)
GOP Length: From adapt to input TS

Video Outputs
Analog Video
Interface: Qty 2 CVBS w/OSD (Rear-BNC-F, Front-BNC-F)
Video Format: PAL-B/G/I/M/N/D, NTSC, and SECAM L/B/G/K1
Screen Proportion: 4:3/16:9
Graphic Process: OSD,
Support graphic display up to 16 bits/pel (OSD)
Synchronization Information (Via DB-9M on rear panel)
Video Synchronous Output SYNC Synchronous line/field/frame output
Synchronous lock output
27M reference clock output

Digital Video
Interface: Qty 1 - SDI via BNC-F

Audio Decoding
Standard: Supports ISO11172-3 and ISO13818-3 audio decoding
Number of Outputs: simultaneous 2 pairs of stereo (4 channels) decoding

Audio Outputs
Analog Audio: 2 channels stereo, balanced via XLR-M on rear panel
2 channels stereo, un-balanced via RCA-F on front panel
Digital Audio: 1 channel of AES/EBU-SPDIF via BNC-F on rear panel

Status Indicators (Front Panel)
LEDs: On/Standby, Decoder Lock Status, ASI Signal Present

Control
RS-232C via DB-9M on rear panel
USB-1 via USB-Type A on rear panel
Software: MS Windows Graphical User Interface Application
(Windows 2000 & XP compatible.)

Electrical Features
Power Supply: 9 to 17 VDC ( External In-Line AC PWR Supply Optional)
Power Consumption: < 45W

Physical
Dimensions: 8.5" (W) x 8.5" (D) x 1.0" (H)
21.6 cm x 21.6 cm x 2.54 cm
Weight: 3.65 lbs ( 1.656 kg)

Environmental Conditions
Operating Temperature: 0 C 50 C
Storage Temperature: -20 C 80 C
Comparative Humidity: 10% ~ 90%, non-condensing