High-Power, Long Range FM Transmitters: CORTEX

CORTEX BLOCK DIAGRAM

Fully MODULAR with Extreme Redundancy

Every part of the transmitter is Redundant: Amplifiers, Exciter, Dummy load etc.
The maximum redundancy is given by the indipendency of the work of the single amplifier, either from the other amplifiers or from the central control logic.
The transmitter can work even without it.

The CORTEX SMP© – Superior Modular Philosophy – is a family based on a very compact Amplifier Module.

It combines 2 to 10 Low Power RF amplifiers to create a High Power FM Broadcast Transmitter.

Thanks to its size, its 2 HE, and its 2,2 kW power levels, it is the most redundant Modular FM Transmitter on the market.

The CELL RF Amplifier has a 2,2kW output power with a High Efficiency Planar LDMOS Technology.

The modular architecture is completed with:

• High Efficiency Solid State FM Amplifiers
• Special combiners
• FM exciters and control logics
• The FM exciter can be Analogue or DDS
• Both with integrated AES/EBU interface
• FM Stereo Transmitter/Exciter
• Built in Stereo Generator

TEKO's unique SMP Radio Equipment Architecture identifies every single modular, enabling each one of them to grow in power (scalar) and in robustness.

SMP, based on combining low-power amplifiers, allows maximum output power even in case of fault with any one amplifier.

SMP is the most Robust Radio Station Equipment on the broadcast chain.

To better understand the benefits of its philosophy, let us explain how a Radio FM Broadcast System works.

What an FM Radio Broadcast System is composed of

It is composed of many parts, such as:

• Transmitter
• Antenna
• Radio Links
• the Mains Electric Supply
• etc.

…..but everybody agrees the king component is the FM Transmitter.

FM Transmitter Structure

It is mainly composed of two parts:
The FM Exciter, also known as FM Modulator, and the output RF Amplifier.

 

When it is necessary to have High Power Transmitters, these are obtained by combining two or more RF Amplifiers.
So, the complete FM Transmitter chain is built as follows:

1. Everything starts with an FM Exciter...
2. Then this low power emitted FM Signal is amplified by several RF Amplifiers and then...
3. this combination creates a Low, Medium or High Power FM Transmission system.

RF Amplifier

The LDMOS, the heart of any RF amplifier, is the active component that produces the amplification.

The LDMOS amplifies the Low Output Power FM Exciter to the high Power at the output of the Transmitter.
The LDMOS has the ability to handle high RF Power levels with a big capacity of Heat Dissipation.

On FM Radio applications, the maximum power handled by the LDMOS with modern technology is about 1kW or 1,5kW.
To reach higher power levels it is necessary to combine them into a bigger unit.

The most common LDMOS devices used in the Broadcast industry at the moment are:

• BLF188.
• BLF189. MRF1K25. MRF1K5
• and MRF1K8.

The strategy used by the Producers is to combine a number of LDMOS into a single Medium Power RF Amplifier.
The RF Amplifiers output power ranges between 1kW and 6kW.
The amplifier is obtained with the combination of a variable number (between 2 and 6) of LDMOS devices. With this number of LDMOS output powers between 2 and 6 kilowatts can be obtained.

High Power FM Transmitter

A High Power FM Transmitter is built combining two or more Medium Power RFs.
It is obtained with the combination of a variable number of these – between 2 and 10.

To achieve this, the constructors choose between four different philosophies:

• Use only one high power FM Amplifier Module.
• Combine High Power Amplifier Modules.
• Combine Low Power Amplifier Modules, “only RF” type: meaning an RF Module without Power Supply, Fans and Control Logic.
• Combine Low Power Stand Alone Amplifier Modules (this is the option adopted for CORTEX).

WHAT A BROADCASTER NEEDS FROM AN FM TRANSMITTER

A few essential things. The transmitter must be:

• Always On-Air: this is the main thing, nothing is more important. It must be reliable.
• Easy to maintain.
• Easy to transport and to handle by one person, so as to avoid the need to have two or more technicians work on it.
• Of low weight – the optimal weight: modules of less than 15 kg (35 lbs).
• Of Low Energy consumption.

CORTEX SMP© Superior Modular Philosophy

To fully meet the Broadcaster needs, we create a modular structure with an RF Amplifier Module, obsessively optimized for the best results.
Big broadcast systems benefit from this optimization.

SMP Superior Modular Philosophy is the synthesis of robustness, easy maintenance and low energy consumption.

CELL RF Amplifier and Pulse Amplifier

To meet all the needs of the broadcaster, the base module CELL Amplifier was extremely optimized so as to maximize:
· Efficiency
· Reliability
· Electrical performance
· Networking
· Easy the maintenance

and to minimize:
· weight
· power
· consumption
· heat produced on the site

This way, the entire system benefits.

A key aspect that helps to make maintenance easy is testing and repairing the amplifier module in a Laboratory, with no special tools required. The module can be repaired even on site!
To allow this, CELL Amplifiers are provided with their own power supply ventilation, control logic and output filter.
Contrary to the standard plug-in transmitters, the Amplifier Module makes maintenance and testing easier: no need of special tools, as each module can be connected and installed or tested as a single amplifier. A single CELL Amplifier can be put on-air as a back-up for a bigger transmitter.

Shock and vibration during the transport process can compromise the result of installation.
Optimizing the CELL Amplifier dimension and weight allows a small and smart package, of low weight and and with the dimensions that help to meet the most demanding transport conditions. In addition, the Hermetic temperature control vibration and Shock isolated light packs ensure the health of the operators is never compromised.

• Last generation 1400 W LDMOS, VSWR > 65:1 @ all Phase Angles, designed for enhanced ruggedness ISM applications and plasma generators.
• Integrated AC Mains filtering.
• Integrated lightning protection.

Hardware and Software Protections:

Over and Under Voltage DC RF and Power Supply Temperature, RF Coaxial Output, Open or Short Circuit, provide a long working time on Short/Open loads at all phases and angles without any damage.
A Delayed energizing of the system after a Mains Power Blackout prevents against peaks and high variation voltages that are typical of this type of events.

• Each module is equipped with a logic controller that allows full control by a local operator.
• All transmitter and amplifier parameters required for diagnostics can be retrieved: Locally Remotely Via standard (IP) protocol With standard software (web browser, SNMP).

KEY FACTS

Combining System:

• Compact and well isolated up to twelve way 20 kW PC Power Combiner.
• Ultra-broadband, phase stable, low loss and showing more than 20 dB of additive harmonic filtering.
• FM transmitters featuring only 800 mm rack depth and up to 40 kW FM in a single 19” rack.
• Digital TV Transmitters up to 8 KW Wide Band Doherty (WBD) output power in a single 19” rack.

WEB/SNMP Telemetry and Remote Control:

• Full Local or Remote control by logon username and password.
• Remote control with Smartphones or Tablet.
• Host Logic and tele-measurement (TM, TC & TA).
• Remote control and monitoring via SNMP and/or WEB interface.
• With logbook or log file to record error or alarm message.
• Display of forward/reflection power value and reflection high alarm.

Human Interface:

• Multilingual user guidance.
• High Definition, high contrast LCD display.
• Quick set of thresholds for protections level.

This set is based on assignment of three “flavors” or PERSONALITIES:

• Conservative (primary target = protect itself).
• Standard (balanced).
• Aggressive (primary target = transmission without interruptions).
• N+1 and Backup systems
• Conventional standby systems such as: exciter standby, (n+1) Transmitter standby, passive standby and active output stage standby can be implemented.
• No additional control units are needed for the exciter standby and the active amplifier standby.

80kW FM Transmitter Series Standard and HOT PLUG-IN versions:

• Audio Source Selection
• Several Transmitter Ranges
• Based Control
• Analogue and Digital Ready for HD Radio and DRM
• Based on CELL Series High Efficiency RF Amplifier Module
• CELL LDMOS Amplifiers 1,1kW or 2,2kW
• Hot Plug-in Power Supply
• Up to 75% Overal Efficiency
• PLANAR LDMOS
• 65:1 VSWR Tollerant
• Fully RF and Power
• Supply
• Redundant TXM SMP

REVOLUTIONARY MODULAR COMBINER:

WE HAVE BROKEN THE PORT NUMBER LIMIT.

• Ultra Compact Design.
• Low power to high power direct stepping.
• Low loss.
• Non-Hierarchical Arbitrary odd and even port number.
• Ground referred balancing loads.
• Extremely high isolation value: more than 26dB.
• Up to 10 input way for 20 kW Output Power.
• Ultra-wideband, exceeds more stringent specifications.
• Phase stable.
• Best in class low loss performance: less than 0.1dB
• More than 12 dB of additive harmonic filtering.
• Low Cost vs Power ratio.

The Combining system is composed of the COMBINER itself, the ISOLATED SPLITTER 2-10 way and the UNBALANCED POWER LOAD 2-10