This part of IEC 62273 gives the conditions for measuring the performance parameters of terrestrial digital transmitters and for facilitating the comparison of measurements which are carried out by different personnel. It contains details of specially selected methods for determining the most important performance parameters of digital transmitters. The measurement methods described apply to a limited number of performance parameters, i.e. those which can give rise to ambiguous interpretation due to the use of different methods and conditions. They are neither restrictive nor mandatory: measurements can be chosen for each particular case. If necessary, additional tests can be carried out but they shall comply with those standards which have been established by other study groups, subcommittees of the IEC or other international or suitably accredited organizations. No limits have been assigned to quantify acceptable ranges of performance parameters. These are judged to be properly included in the technical specifications for individual transmitters; however, the terms and the manner used to quantify them should ideally be those described in a future IEC publication. The measurement methods described in this standard are intended for type approval tests. However they can equally well apply to acceptance tests measurements and quality control tests either in factories or on site. Test signals are used to measure performance parameters for both digital and analogue terrestrial transmitters. Their electronic characteristics and their associated performance parameters are widely understood. The test signals are measured after they have gone through the transmitter equipment to determine if their degradation is within the required quality criteria. This standard does not go into any detail regarding MPEG 2 signals or DVB processes nor does it deal with digital signal processing.