Multiple Sub-Nyquist Sampling Encoding - Technical Specifications

Technical Specifications

• Aspect Ratio: 16:9
• Scanlines (compressed/active/total): 1,032/1,035/1,125
• Pixels per line (approximately): 1060 (still image)/530 (moving)
• Horizontal lines per picture height: 598 (black-and-white)/209 (chroma)
• Interlaced ratio: 2:1
• Refresh rate: 60.00 (in order to improve compatibility with 50 fields/sec systems).
• Sampling frequency for broadcast: 16.2 MHz
• Vector motion compensation: horizontal ± 16 samples (32.4 MHz clock) / frame, a vertical line ± 3 / Field
• Audio:48 kHz 16bit（2ch）／32 kHz 12bit（4ch:3.1）

DPCM Audio compression format: DPCM quasi-instantaneous companding

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 Y is 20 MHz, and the pre-compression bandwidth for chrominance is a 7 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 Y/C NTSC signal - with the Y at the lower frequencies and the C 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 Y and C. This reduces the effective frequency range and lowers the required power. Approximately 570 W (360 for Y and 210 for C) would be needed in order to get a 40 dB of signal to noise ratio for a separate Y/C 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 lack of visual response to low frequency noise allows significant reduction in transponder power if the higher video frequencies are emphasized prior to modulation at the transmitter and then de-emphasized at the receiver. This method was adopted, with crossover frequencies for the emphasis/de-emphasis at 5.2 MHz for Y and 1.6 MHz for C. With this in place, the power requirements drop to 260 W of power (190 for Y and 69 for C).