or 4-channel digital audio system: 48 kHz/16 bit (2 channel stereo: 2 front channels)/32 kHz/12 bit (4 channel surround: 3 front channels + 1 back channel) DPCM Audio compression format: DPCM quasi-instantaneous companding Required bandwidth: 27 MHz Colorimetry The MUSE luminance signal encodes , specified as the following mix of the original RGB color channels: The chrominance signal encodes and difference signals. By using these three signals (, and ), a MUSE receiver can retrieve the original RGB color components using the following matrix: The system used a colorimetry matrix specified by SMPTE 240M (with coefficients corresponding to the SMPTE RP 145 primaries, also known as SMPTE-C, in use at the time the standard was created). The chromaticity of the primary colors and white point are: The luma () function is specified as: The blue color difference () is amplitude-scaled (), according to: The red color difference () is amplitude-scaled (), according to: Signal and Transmission MUSE is a 1125 line system (1035 visible), and is not pulse and sync compatible with the digital 1080 line system used by modern HDTV. Originally, it was a 1125 line, interlaced, 60 Hz, system with a 5/3 (1.66:1) aspect ratio and an optimal viewing distance of roughly 3.3H. For terrestrial MUSE transmission a bandwidth limited FM system was devised. A satellite transmission system uses uncompressed FM. The pre-compression bandwidth for is 20 MHz, and the pre-compression bandwidth for chrominance is a 7.425 MHz carrier. The Japanese initially explored the idea of frequency modulation of a conventionally constructed composite signal. This would create a signal similar in structure to the composite video NTSC signal - with the (luminance) at the lower frequencies and the (chrominance) above. Approximately 3 kW of power would be required, in order to get 40 dB of signal to noise ratio for a composite FM signal in the 22 GHz band. This was incompatible with satellite broadcast techniques and bandwidth. To overcome this limitation, it was decided to use a separate transmission of and . This reduces the effective frequency range and lowers the required power. Approximately 570 W (360 for and 210 for ) would be needed in order to get a 40 dB of signal to noise ratio for a separate FM signal in the 22 GHz satellite band. This was feasible. There is one more power saving that appears from the character of the human eye. The