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• Overview and Key Features
• System Description
• Product Guide
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• Customer Installs: HFC Extensions
• Customer Installs: CaTV Links
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Customer Installs CaTV Links

Cable System Expands with AML Link

From left to right: Henry Ketner with Hilario Baltazar, Alejandro Baltazar and jorge Alejandro Baltazar at the conclusion of the training in Torrance, California.

Mexican Cable Operator Sistema de Comunicaciones de Quiroga has started to provide cable service to the towns of San Andres and Eronguaricaro in the state of Michoacan (Mexico) from an existing headend at Quiroga.

Two AML links fed from the same transmitter were used to transport the 65 channels from the headend to the two towns at distances of 11 Kms and 25 Kms respectively. The second of the paths is mostly over water, crossing Lake Eronguaricaro.

Following a site evaluation survey, a transmitter site was selected near the Quiroga headend, from which there was good line of sight to the two towns. The headend signal was transported to this site by a 2.5-mile (4 Kilometer) fiber link. Following the installation and commissioning of the two links, the cable operator is now providing 65-channel cable service in both towns.

According to Alejandro Baltazar, General Manager of the company, “we are extremely pleased with the performance of the system. We did all the installation ourselves with some guidance from Cable AML and we have been able to start providing cable service to an area where it as imperative to offer service quickly and at low cost. Due to the relatively short straight-line distance over Lake Eronguaricaro, the only other alternative was to install a long and costly fiber link or to purchase, install and operate two additional headends. We strongly recommend the Cable AML solution to any cable operator in Mexico that needs to transport the cable signals efficiently and easily”.

44 Mile Inter-Island Digital Video Backbone

Cable AML has provided a cost effective state-of-the art system to transport video feeds from the US Virgin Island’s Legislature in St Croix to the nearby island of St. Thomas.

The system’s first two hops are implemented with an 18 GHz FM modulated link carrying video and stereo audio from the USVI Government building in Fredricksted (St. Croix) to a relay repeater on St Georges Hill (1.75 miles) and then to a receiver at Blue Mountain (4.45 miles).

To minimize cost and complexity, an on-frequency repeater at St Georges Hill was used to avoid de-modulation, re-modulation and signal processing associated with conventional video repeaters.

At Blue Mountain the video and audio feeds are QPSK-modulated and frequency-multiplexed for transport by a 13 GHz bidirectional broadband link to the nearby island of St. Thomas (a distance of 44 miles).

The receiver at St Thomas recovers the baseband video and audio for transmission to the Government facility and the local cable system (Innovative Cable).

The inter-island QPSK link provides a bidirectional backbone with sufficient capacity to allow expansion for transport of more video programming or additional data carriers.

Anthony Ramirez adjusts the 4 ft 18 GHz receiver antenna at the St. George repeater site.	St. George repeater site at St. Croix in the US Virgin Islands.	From left to right: Bernard Rey, System Engineer of Innovative Cable in St. Thomas, Douglas Pompey, System Engineer of Innovative Cable in St. Croix and Toya Malone, Media Director for the government of the USVI, at the interisland 13 GHz QPSK transceiver in St. Thomas.

New AML Link Goes up in Tamaulipas (Mexico)

AML Antenna with Radom.

A point-to-point AML link which 80-channel capacity has been installed by Telecomunicaciones de China in the city of China (Tamaulipas, Mexico) to transport Cable TV signals from the local headend to the city of General Bravo, over a distance of 8 miles.  

The system was installed and commissioned by Ing. Alma Alarcón and Ing. Jesús Chacón following the training course at Cable AML’s facilities in Torrance, California.

The transmit antenna was mounted on a T45 tower at a height of 27 meters and the receiver antenna at a height of 40 meters. Because of the high winds prevalent over the area, radomes were installed on the antennas to minimize wind damage.

According to Ing. Alarcón, “the AML link is allowing us to offer Cable TV service in General Bravo with excellent signal quality and at a much lower cost than any of the alternatives available”.

Cable One Installs Multichannel HDTV Link

Elvis Brown of Cable One installs the Headend Hardware for the Multichannel HDTV Link

US Cable Operator Cable One has upgraded a 23-mile FM link in Clarksdale, originally used to transport seven distant TV stations, to now transport SDTV and HDTV digital signals with 8VSB modulation.

The traditional way to transport HDTV signals, which was to demodulate them to ASI Transport Streams and then to transmit each one through a digital radio, is very expensive for a multi-carrier application. The method implemented by Cable AML is the least complex, least expensive and most reliable approach. The 8-VSB modulated, 6 MHz-wide digital signals were frequency-multiplexed and transported through a  broadband Cable AML transmitter.

At the receive site the AML receiver delivers all the carriers on a single cable, which is linked to the headend. The 8VSB signals can be demodulated to ASI and/or baseband audio and video, depending on how they are to be used. 

The antennas and waveguide previously used for the FM microwave were suitable for the broadband AML transport of the 8VSB signals. Using the same antennas and waveguide, allowed
an electronics only upgrade to a digital link, minimizing the cost and installation time.

AML Link Transports FM and Digital 8VSB Video

US Cable operator ADELPHIA has upgraded an existing Cable AML link to provide for transport of high-quality 8VSB-modulated off-air TV signals from a remote location to the central headend.

The link was originally installed several years ago to transport a number of distant off-air channels into Susanville (California). The Cable AML equipment replaced old channelized FM video radios that had developed serious reliability issues.

When the digital 8VSB off-air signals became available, Cable AML analyzed the possibility of transporting the digital carriers through the existing AML radios and concluded that it could be done by just upgrading the IF output of the receiver.

The digital 8VSB carriers were then added to the existing link together with the FM video channels. According to Mike Miller of Adelphia, “with the combined analog and digital signals, the AML link has been performing superbly”.

Block diagram of FM and 8VSB Transport System.

AML Transports HDTV Off-Air Channels

Cable AML’s Lorrie Kaufman and Martin Schooley of Cable One inspect the HDTV transmitter.

AML links continue to be used by many Cable TV operators to transport off-air TV signals from nearby cities to the cable system Headend.

Cable One wanted to transport TV off-airs from the Houston TV stations to the cable system in Fort Lavaca (Texas), about 140 miles away. Due to the large distance between the two sites and the difficult propagation environment in the area, the reliability of the direct pick up signals was poor, which is why Cable One had been using a 6 GHz FM Common Carrier Link with 3-channel capacity to transport analog signals from an intermediate point between the two locations.

When the need arose to transport the new HDTV channels and to add additional analog channels, the 6 GHz link was no longer a feasible solution. Cable AML has provided an enhanced 13 GHz digital AML link that transports the added channel load as well as the HDTV channels.

Martin Schooley, Technical Operations Manager of Cable One, said he is very much looking forward to this upgrade of the old analog link, “It is something I have fought over for a long time”, he said.

Mediacom Installs Digital TV PTP Link

Mediacom off-air receive site.

Mediacom recently installed a Cable AML digital link to dramatically improve the off-air signals in Sun City California. The links uses Cable AML’s Digital Headend Module.

Local-into-local DBS carriage of off-airs represents a serious competitive problem when the CATV operator suffers from less than perfect off-air pickup.

By using digital technology for transport, Cable AML provides a significant improvement in picture quality as well as an reduction in required microwave spectrum or an increase in signal carriage capability. Each Cable AML Digital Headend Module can digitize as many as six video programs into a single 6MHz channel for high quality transport over new or existing microwave links.

High Power Outdoor Transmitter Delivered To US Media

Outdoor High Power 13 GHz Transmitter.

Cable AML has shipped the first of its new product range of High Power Outdoor transmitters and repeaters. The transmitter has been installed in Truckee, California, to replace an indoor unit.

Both the ITX-011 and ITX-050 models are now offered in outdoor versions. The OTX-011 has the equivalent output power of a 25W amplifier, several times more powerful than any previous outdoor transmitter. The OTX-050 has the equivalent output power of a 50W amplifier.

With the new transmitter, waveguide attenuation is reduced and the cost of air-conditioning requireis avoided.

Cable AML has been delivering high power outdoor transmitters and transceivers operating in the 23, 26 and 28 GHz bands for over five years. At these millimeter wave frequencies even a 10’ (3m) waveguide causes unacceptable attenuation, so outdoor high power devices are mandatory. The outdoor technology has now been made available for 13 GHz transmitters.

Adelphia Upgrades To Digital Microwave

Adelphia’s Jay Rease during system training at Cable AML’s facilities in Torrance, CA.

A Cable AML wireless network carrying digitized television and Internet backbone data now provides several smaller California communities with the same level of service available in larger communities served by metropolitan fiber.

The system transports fourteen NTSC television off-air channels and 100Base T data. The signals are MPEG-2 encoded, multiplexed, and modulated using Cable AML’s DHM-4001 digital headend mod-ules. The QPSK-modulated video is multiplexed with the Ethernet data and transported 26 miles (42 km) to a bidirectional repeater site and then on to two communities, one 35 miles (56 km) away and the other 16 miles (25 km) away.

By adding Internet backbone capacity to a digitized video backbone transport link, Adelphia can offer much higher data rates to its DOCSIS cable customers at a low incremental capital cost and without paying monthly transport fees to the common carrier.

Adelphia Upgrades Microwave Link

Adelphia’s Cable System in Yuma, Arizona, has been providing the Yuma Proving Grounds with Cable TV service for several years with a 54 - 550MHz link from Cable AML. This 16-mile (26 Km) link was recently upgraded to a full wireless HFC extension, using a pair of TRX18-002 transceivers operating in the 18 GHz frequency band.

Dual Redundant 8 GHz Receivers for Digital AML Link The upgraded system expands the downstream path to 550 - 750 MHz and provides a 5 - 42 MHz upstream path for cable modem return signals.

The wireless HFC extension crosses the Colorado River at one of its widest points. “The Cable AML dual-frequency link has been performing perfectly” said Hugh Williams.

More 18 GHz Repeaters Installed And Commissioned In China

18 GHz Repeater with Input Antenna18 GHz Repeater with Sector Output AntennaCable AML is supplying additional 18 GHz repeaters to increase the coverage of a system providing multi-channel digital television to subscribers in China. Two high-gain Repeaters have already been commissioned and two additional units are being delivered to the system, which carries 20 QPSK carriers with a capacity for more than 100 programs through a major metropolitan area.

As shown in the photographs, the repeaters feature rugged outdoor housings to withstand the strong winds that are common in the area during the monsoon season.

Two-Way AML System For ATT-Comcast

Another state-of-the-art, two-way AML system has been delivered to ATT-COMCAST for installation in an HFC cable system in California.

The system is designed to provide two-way cable modem service to communities served by microwave.

With the new system, it is possible to increase the downstream digital channel carriage capacity of an existing AML link by expanding the downstream into the 550 to 750 MHz range and the upstream band in the 5 to 42 MHz range. 

This makes it possible to simultaneously increase channel capacity and provide two-way DOCSIS cable modem service to three different receiver sites from a central hub.

Refurbished AML Carries Broadband Signals

Cable Operators are ordering Cable AML refurbished equipment for a cost-effective way to feed remote subscriber pockets and to improve signal quality of off-air TV signals.

For example, the customer-owned equipment shown in the photograph was re-deployed by a major system operator to serve a smaller CATV system which is 25 miles from the nearest major market. The system had been suffering from poor off-air signals and high T-1 costs for their Cable Modem service.

Cable AML can bring you higher-quality signals and can expand your service area using cost-effective solutions with refurbished and recertified broadband AML equipment.

Small Subscriber Pockets Served Cost-Effectively with ITX-011 Broadband Transmitter

The cost of providing cable service to to a small California community within a franchise area was minimized thanks to a well designed AML system. The Cable AML model ITX-011 broadband transmitter is the cornerstone of this system.

The 13 GHz transmitter has the capability of providing high-quality analog or digital TV signals in a 17 mile (28 Kilometer) link.

With a one-way capacity of 80 analog channels, the link is designed to be easily upgraded for two-way service if, and when, cable modems are installed in the service area. Moreover, the ITX-011 system architecture enables the operator to upgrade the transmitter to a higher power configuration if required.

A veritable workhorse in service at many cable systems, the ITX-011 includes an "F" connector port and a toggle switch at the front panel to facilitate diagnostics by allowing rapid comparison of the transmitter input and output signals at VHF.

Broadband High Power Solid State Transmitter Replaces Channelized Unit

A broadband, high-power AML transmitter has been delivered to a cable system to replace an older, channelized unit that provided service for many years to an isolated island community in the US.

The new transmitter will make it possible to provide any mix of analog and digital channels, thus allowing additional channels and digital service upgrades without hardware changes. It operates over a 13 mile (21 Kilometer) link feeding a broadband active repeater. The combined transmitter-repeater link spans a distance of over 20 miles (32 Kilometers).

The ITX-1300S is Cable AML's highest power transmitter operating in the 12.7 to 13.2 GHz CARS (Community Antenna Relay Service) band. It replaces a large room full of Hughes channelized STX-141 transmitters, each of which was designed to transmit only one analog VSBAM channel. The ITX-1300S incorporates solid state GaAs FET power amplifiers with built-in redundancy and a state-of-the-art dual feed-forward control loop. It is designed to power high-reliability links operating at full capacity over difficult propagation environments.

Broadband Transmitter Replaces Channelized Unit

Cable AML continues to deliver broadband AML transmitters to replace older channelized units. Operational savings in power consumption and reduced repair and maintenance costs provide ample financial justification for replacing aging channelized units that serve fewer paths than when originally installed.

Operators often mention the carriage of the new HITS digital signals and/or the carriage of the data carriers to support DOCSIS and interactive set-tops boxes as additional reasons for upgrades to broadband microwave. Contact Cable AML application engineering for details.

High Power Broadband AML System Upgrade

Cable MSO's continue to upgrade microwave distribution systems originally installed in the 80's with modern, broadband AML transmitters that offer substantial operational advantages and savings. The latest example is Cable AML's ITX-1260D Dual Redundant Transmitter, the most powerful broadband transmitter in the world, which has replaced an STX-141 klystron-based system consisting of sixteen bays, each8 feet (2.4 meters) high.

The new system has yielded better signal quality throughout the cable plant. Additional benefits from the upgrade are the extra space available at the headend (which was used to accommodate new cable modem and VOD equipment, reduced power consumption (from 280,000 KWhr/year to less than 20,000 KWhr/year), reduced A/C (Air Conditioning) maintenance and operating costs and significantly improved headend noise environment.

Bidirectional Link Provides Cost Effective Multi-channel FM Transport

The cost and performance advantages of AML systems for multi-channel FM transport have been proven once again with the installation of an 18 GHz system to transport ten FM channels between islands at a distance of 13.2 miles (21.1 kilometers). The system is in the downstream of a two-way multi-channel point-to-point link. In the upstream direction, VSBAM / 64 QAM signals are carried in the 13 GHz band.

The system was designed to transport high-quality, high-reliability FM signals which originate from a multi-channel 13 GHz AML link feeding a fiber run, which in turn feeds the 18 GHz AML link. An integrated broadband receiver feeding high-quality FM demodulators at the receive end provide multi-channel transport at a fraction of the cost available with either fiber or with stacked single-channel FM radios.

13 GHz Space Combining Implemented with ITX-100 Power-Doubling Transmitter

Space combining can be an effective technique for selectively adding channels and/or increasing power on a specific point-to-point path. The technique was adopted to feed one of several AML receive sites with a different channel line-up than the others.

The additional channels required at the site were fed to a separate broadband transmitter and connected to a separate antenna which illuminates the particular receive site. The channels are received in their respective frequencies by the standard AML broadband receiver, combining in space with the channels already being sent to this and all the other AML sites.

Cable AML's model ITX-100 power-doubling transmitter was used for this application due to the high power required and the built-in redundancy of this type of transmitter.

8 GHz Link Improves Signal Reliability

Neville Greene checking power levels during hands-on training session Several years ago, Cable AML developed 8 GHz AML systems in order to provide reliable signal transportation in adverse rainfall environments.

We have just delivered another 8 GHz AML system for this purpose. The system was designed to replace an 18 GHz link which had been suffering excessive loss of signal during the intense rain periods common to the area.

A broadband transmitter and receiver pair, complete with Pilot Tone for frequency locking and receiver VHF AGC were delivered and successfully installed.

The system, operating in the 7861.905 to 8358.905 MHz band, is now in use with a channel loading of 40 analog video channels.

Cost Effective Link Combining AML and FML

IRX-111 Indoor Broadband Receiver used in FM multi-channel transmission Cable AML has supplied a very cost-effective broadband FM link for transport of multi-channel TV broadcast signals in a multi-hop configuration involving fiber and microwave. The link involves transporting, via fiber, several CARS-band (13 GHz) FM single-channel signals from a receive location at a distant point to a Cable AML 18 GHz broadband transmitter for transmission to a 21 Km link over water.

Single-channel multi-hop FM video links have been in operation for many years. As operators need to add channels or to transport digital signals, stacking single-channel radios becomes more costly and less effective.

The Cable AML approach bundles the signals to eliminate the need for channel-by-channel demodulation/modulation of the multi-channel signal at each hop, whether fiber or microwave, thereby reducing system complexity and cost.

Using AML to Transport Digital MPEG2 Carriers

Cable AML radios can provide significant cost savings when used to transport HITS (Headend in the Sky) signals from one headend to neighboring headends.

The HITS system delivers QPSK digital signals to cable headends via satellite. Each carriers is modulated with five to eight digitally compressed video programs at 27 Mbps. At each headend the HITS signals are downconverted and their modulation is changed from QPSK to 64-QAM so that each carrier fits within the standard 6 MHz channel bandwidth. From one to fifteen digitally modulated 64-QAM carriers can be carried in the cable plant.

Four ATX-033 transmitters racked to provide digital signal to 4 separate headends Cable AML's broadband system can be used to transport the 64-QAM carriers from a master headend to nearby headends, thus avoiding the expense of duplicating the HITS satellite receiver and trans-modulation equipment.

Tests of standard production Cable AML's broadband transmitters and receivers were made at the National Digital Television Center by R&A Management, GI, TCI, and Cable AML to characterize the performance of the equipment when used in the digital-only transport mode.

Cable AML's links are also used by Cable TV Operators to transport a combination of analog and digital signals. For example, a typical combination might include 56 VSB-AM analog video channels, 15 digital video carriers (64-QAM), and several QPSK data carriers. The data carriers are for EPG (Electronic Program Guide) information, conditional access, control data, and DMX (Digital Audio Signal).

Cable AML Delivers 18 GHz System with Analog, Digital, & Two-Way Capability

18 GHz two-way system elements with upstream components, down-stream components and outdoor downconverter of the SRX18-201 receiversCable AML has delivered a two-way, 18 GHz system designed to transmit a combination of analog and digital signals both downstream and upstream.

The downstream load consists of a total of twenty five TV channels (thirteen NTSC channels and ten PAL B channels), plus two E1 digital data channels. The upstream load includes twelve PAL B TV channels and data channels.

The system incorporates an ITX18-005 transmitter and an SRX18-201 phase-locked receiver at the headend site and a second ITX18-005 transmitter and an SRX18-201 Composite AGC receiver at the remote hub located 5 Km away.

The SRX series receivers are two-piece receivers, with an outdoor downconverter mounted directly on the antenna to minimize waveguide loss; and an indoor VHF Processor unit that connects to the Downconverter with standard cables.

As with all Cable AML broadband products, the transmitters and receivers are digital-ready. This is but one more in a long list of examples of Cable AML's world class wireless system design and implementation capability. Cable AML has routinely solved hundreds of wireless application challenges of every type.

High Capacity 28/31 GHz Two-Way Multi-Carrier Link Installed

Two-Way Multi-Carrier STL (Studio-To-Transmitter Link)Cable AML has installed a high-capacity, two-way, multi-carrier STL (Studio to Transmitter Link) operating in the millimeter-wave bands of 27.5 - 28.0 GHz (downstream) and 31.0 - 31.3 GHz (upstream). The link is designed to interconnect an LMDS headend with a remote Base Station featuring Cable AML's wideband, high-power transceivers.

Cable AML's broadband multi-carrier system design makes it possible to interconnect several base stations to a single LMDS headend where all the digital modulation and demodulation equipment is housed, reducing system cost and complexity.

Conventional system designs based on single-carrier radios are implemented with one full duplex link per carrier and require digital re-modulation at each base station. Cable AML multi-carrier approach drastically reduces the cost and complexity of the interface equipment between the STL and the LMDS transceivers at each base station.

Multiple Headends Replaced by Broadband AML System

The third Canadian installation of Cable AML's new ITX-100 high-power transmitter was completed in March by Cable AML distributor Capella Telecommunications.

The ITX-100 transmitter is part of a microwave distribution network which also utilizes a very high power ITX-500 transmitter and an IAR-011 repeater. Cable AML's ORX-201 phase-lock, low-noise receivers are used for large distribution areas, and refurbished receivers are used to serve areas with as few as 100 subscribers.

The ITX-100 is ideal for digital (or analog plus digital) transmission due to its unique architecture that offers fail-soft performance in the event of the failure of a power amplifier or its power supply. The fail-soft architecture avoids the disruption to the digital signals that may occur when transmitters are switched into redundancy.

A total of 13 headends were replaced by this Cable AML system. The AML network now delivering 60 analog television channels was designed with a 78 channel capability to accommodate a projected growth in the near feature.

Affordable Two-Way Multi-Channel FM Link

Two-Way FM System Cable AML has provided a cost effective solution to satisfy a customer requirement to transmit computer graphics data between two school sites located less than a mile (1.6 kilometers) from each other. The system is built around the low cost ITX-000 transmitter and the IRX-001 receiver currently lightly loaded.

Additional VSBAM, digital, and FM carriers can be easily added in both directions. Unlike conventional channelized FM systems (where each new channel requires separate transmitter and receivers), the Cable AML system allows the operator to increase channel capacity by simply adding additional FM modulator cards and low-cost FM demods.

Point-to-Point AML System Carries Analog Video & Two-Way Data Simultaneously

Point-to-Point AML SystemCable AML has delivered a duplex AML link designed to simultaneously transmit multi-channel video and data in both directions. The system is used to connect a headend with a remote MMDS transmission site approximately 20 miles (44 km) apart. In the downstream direction the system is capable of transmitting 31 VSBAM adjacent video channels (189 MHz bandwidth) in the 13.0 to 13.189 GHz band and several QPSK-modulated data carriers with data rates between 2 Mbps and 10 Mbps each total bandwidth available of 125 MHz. The data carriers are also transmitted upstream for a full duplex two-way data capability.

The system's integrated data modems interface directly with the customer's LAN (Local Area Network) through an Ethernet RJ-45 connector. The RF components of the system at the headend are an ITX-011 indoor broadband transmitter sending video and data upstream, and an IRX-001 indoor receiver receiving data coming downstream. At the remote MMDS transmit site, the key elements are an IRX-201 indoor receiver and an ITX-001 indoor broadband transmitter. The system is designed with full coherency to ensure high video fidelity and low BER (Bit Error Rate).