Page 27 - Electrical Engineering Dictionary

than the thermal energy kT . Contrast with ty of the image. For example a leak factor of
3-level laser. 31 the prediction decay is maintained at the
32
center of the dynamic range.
45 Mbs DPCM for NTSC color video
a codec wherein a subjectively pleasing pic-
31
ture is required at the receiver. This does X = 128 + X − 128 .
−
−
L
not require transparent coding quality typical 32
of TV signals. The output bit-rate for video Finally, a clipper at the coder and decoder
matchestheDS344.736Megabitspersecond is employed to prevent quantization errors.
rate. The coding is done by PCM coding the
NTSC composite video signal at three times 90% withstand voltage a measure of
the color subcarrier frequency using 8 bit per the practical lightning or switching-surge im-
pixel. Prediction of current pixel is obtained pulse withstand capability of a piece of power
by averaging the pixel three after current and equipment. This voltage withstand level is
681 pixels before next to maintain the sub- two standard deviations above the BIL of the
carrier phase. A leak factor is chosen before equipment.
computing prediction error to main the quali-

c
2000 by CRC Press LLC