but NHK abandoned all composite encoding systems. Because of the use of satellite transmission, Frequency modulation (FM) should be used with power-limitation problem. FM incurs triangular noise, so if a sub-carrierred composite signal is used with FM, demodulated chroma signal has more noise than luminance. Because of this, they looked at other options, and decided to use component emission for satellite. At one point, it seemed that FCFE (Frame Conversion Fineness Enhanced), I/P conversion compression system, would be chosen, but MUSE was ultimately picked. Separate transmission of and components was explored. The MUSE format which is transmitted today, uses separated component signalling. The improvement in picture quality was so great, that the original test systems were recalled. One more power saving tweak was made: lack of visual response to low frequency noise allows significant reduction in transponder power if the higher video frequencies are emphasised prior to modulation at the transmitter and de-emphasized at the receiver. Technical specifications MUSE's "1125 lines" are an analog measurement, which includes non-video scan lines taking place while a CRT's electron beam returns to the top of the screen to begin scanning the next field. Only 1035 lines have picture information. Digital signals count only the lines (rows of pixels) that have actual detail, so NTSC's 525 lines become 486i (rounded to 480 to be MPEG compatible), PAL's 625 lines become 576i, and MUSE would be 1035i. To convert the bandwidth of Hi-Vision MUSE into "conventional" lines-of-horizontal resolution (as is used in the NTSC world), multiply 29.9 lines per MHz of bandwidth. (NTSC and PAL/SECAM are 79.9 lines per MHz) - this calculation of 29.9 lines works for all current HD systems including Blu-ray and HD-DVD. So, for MUSE, during a still picture, the lines of resolution would be: 598-lines of luminance resolution per-picture-height. The chroma resolution is: 209-lines. The horizontal luminance measurement approximately matches the vertical resolution of a 1080 interlaced image when the Kell factor and interlace factor are taken into account. Key features of the MUSE system: Aspect ratio: 16:9 Scanlines (total/active): 1,125/1,035 Pixels per line (fully interpolated): 1122 (still image)/748 (moving) Reference clock periods: 1920 per active line Interlaced ratio: 2:1 Aspect ratio 16:9 Refresh rate: 59.94 or 60 frames per second Sampling frequency for broadcast: 16.2 MHz Vector motion compensation: horizontal ± 16 samples (32.4 MHz clock) / frame, a vertical line ± 3 / Field Audio: "DANCE" discrete 2-