A modular approach to solid state AM broadcast transmitters

The gradual movement from transmitters employing thermionic valves to transmitters using transistors has almost always been accompanied by the use of a 'modular' form of construction. For powers exceeding 100 Watts or so a multiplicity of devices is required. There are technical problems in merely connecting the devices in parallel or series, so the resultant circuitry obviously divides into a number of blocks and can be constructed as such. However, there are decisions to be made concerning just what constitutes a 'module'. This paper addresses some of these questions without necessarily giving definite answer but giving examples of solutions. The type of transmitters the author has been concerned with have been relatively low power medium frequency amplitude modulated transmitters. The examples, therefore, concern mainly this type of transmitter, but may have relevance to other power levels and frequency bands.<>