On NAB 2013, Rohde & Schwarz provides an extension of R&S®THU9 with up to 50kW output power with solid state technology. With higher redundancy, more safety in operation and an easier service concept at comparable efficiency values, R&S®THU9 is the first solid state transmitter seriously to be considered to replace IOT systems.Find more information in our brochure
The best energy efficiency technology for broadcast systems today is the Doherty amplification. Before now, IOT transmitter systems had to be used for very high output powers. Doherty technology has led to the development of very successful, highly efficient digital TV transmitter systems.
This document describes how Rohde & Schwarz has applied Doherty technology to digital TV transmitters. It demonstrates the advantages of a solid state transmitter design over IOT technology for very high output powers.
The amplification of the peak and average power signals is separated by using a main and a peak amplifier path. The main amplifier operates as a normal broadcast amplifier until it backs off. The peak amplifier joins the main amplifier in amplifying peak signals. Both amplifier outputs are then combined to produce the final output power.
Intelligent amplifier design using Doherty technology is the new method for increasing the system efficiency of solid state transmitters to 42% for the ATSC standard, putting them on par with IOT transmitters.
Rohde & Schwarz provides the widest range of transmitter systems with Doherty technology. All available standards such as ATSC, DVB-T/DVB-T2 and ISDB-T/ISDB-TB are supported. The air-cooled R&S®TMU9 and the liquid-cooled R&S®THU9 transmitter families achieve previously unattained energy efficiency with significantly reduced operational costs. With hundreds of different configurations, the product range provides broadcast network operators with the best solution for any application.
The Doherty technology based R&S®TMU9 and R&S®THU9 transmitters have already been installed in several countries around the world. Broadcast network providers appreciate the high power efficiency and easy maintenance. Doherty technology from Rohde & Schwarz can be found in many different transmitter configurations and power classes in many regions all over the world.
In the history of terrestrial broadcasting, Rohde & Schwarz has proven its role as an innovation leader. The company has introduced several new technologies onto the market, such as the recently successfully introduced Doherty technology for solid state transmitters.
50 kW output power for ATSC makes the solid state transmitter with Doherty technology a serious contender for re-placing high-power IOT transmitters.
An IOT transmitter system requires about 40 000 Volts to operate. For safety reasons, replacing a heavy, inductive output tube requires special equipment and at least two people.
Unlike an IOT transmitter system, the R&S®THU9 has a simple servicing concept and no special safety requirements.
IOT transmitter systems are mostly operated with two tubes. If one tube fails, the whole system only delivers about 50 % of its maximal output power.
In a solid state transmitter system for high output powers, the redundancy is outstanding due to power supplies and many power amplifiers.
Spare part handling could be easy if smaller spare parts were used compared to a big, heavy and also expensive inductive output tube.
The R&S®THU9 has lower service and maintenance requirements than an IOT transmitter system.
An IOT transmitter can only achieve high power efficiency when running at its nominal power.
Unlike an IOT transmitter system, the R&S®THU9 can provide the exact power a broadcast network provider needs – for all power levels up to 50 kW – at a constant level of power efficiency.
Doherty technology in solid state transmitter systems now offers another solution for very high output powers. The comparison between solid state and IOT technology shows that solid state transmitters with Doherty technology in the Rohde & Schwarz system design provide a number of technological advantages.
Rohde & Schwarz technology delivers highly redundant solid state transmitter systems for digital TV. The benefits of high redundancy, constant efficiency, simple and safe operation, and less maintenance and service make solid state the better choice.