This International Standard applies to the sound/data decoder unit of a receiver for the direct reception of satellite broadcast transmissions of digital subcarrier NTSC signals in the 12 GHz band. The channels are those defined by WARC BS-77 and the system is defined by CCIR Recommendation 650 [2]. The object of this standard is to define the conditions and methods of measurement to be applied. This standard does not specify performance requirements. The decoder unit is usually integrated into a DBS tuner. However, the methods of measurement for the DBS tuner, excluding the decoder unit, are described in Pa rt 2 of this standard.