The standard conditions of measurement and the methods of measuring the characteristics given in this standard are common to sub-systems of terrestrial line-of-sight radio-relay systems and to simulated radio-relay systems using frequency modulation. The tests described are limited to analogue transmission systems. These test methods are general and are applicable to systems of large and small capacity, but it may be unnecessary to specify and to measure some of these characteristics for systems having a capacity of 60 telephone channels or less. The tests to be made should be agreed upon between the parties concerned. Methods of measurement for parameters which are related to a specific baseband signal, such as frequency division multiplex telephony, television or sound-programme transmission, are given in the appropriate sections of I E C Publication 487-3: Methods of Measurement for Equipment Used in Terrestrial Radio-relay Systems, Part 3: Simulated Systems.