0195136047.pdf

15.2 ANALOG COMMUNICATION SYSTEMS 705

Beginning of

first field

Beginning of

second field

485 lines

in picture

End of

second field

End of

first field

Retrace

Retrace

ac

b d

Figure 15.2.26Interlaced scanning

pattern to avoid flickering.

Color burst of 8 cycles

minimum of 3.579545 MHz

Peak carrier level (100%)

Blanking level (75%)

Reference black level (70.3%)

Reference white level (12.5%)

Visual signal

Visual signal

0.18Th

t

Th = 63.556 μs

(one line)

Sync pulse

Figure 15.2.27TV waveform

representing one horizontal line

of a raster scan.

• [m^2 I(t)+m^2 Q(t)]^1 /^2 : Saturation or color intensity. A very deep red is saturated while red
  diluted with white to give a light pink is nearly unsaturated.


• tan−^1 [mQ(t)/mI(t)]: Hue or tint.


• SI(t),SQ(t): Filtered chrominance signals ofmI(t),mQ(t) by low-pass filters.SI(t) modulates
  a color subcarrier at a frequency of 3.579545 MHz±10 Hz via DSB.