A SET consists of a unit or units and the assemblies, subassemblies, and parts connected or
associated together to perform a specific function. A good example of this is a radio receiving set or a
radio transmitting set.
Figure 1-4 is a block diagram of a radio transmitting set. It consists of a radio-frequency amplifier
unit (1), a radio transmitter unit (2), a power supply unit (3), and an antenna coupler group.
Figure 1-4.Radio transmitting set.
A GROUP is a collection of units, assemblies, subassemblies, and parts. It is a subdivision of a set or
system, but it is not capable of performing a complete operational function. The coupler requires power
and signals from the radiofrequency amplifier unit for operation. An example is the antenna coupler group
in figure 1-4.
A UNIT is an assembly or any combination of parts, subassemblies, and assemblies mounted
together. A unit is normally capable of independent operation in a variety of situations. An example of a
unit might be a power supply.