Tektronix 1740A/1750A Instrukcja Użytkownika Pobierz pdf (Strona 93)

Basic Measurements

1740A/1750A Series Waveform/Vector Monitor User Manual

4-12

PAL

The 1751A uses a series of dots around the compass rose

with a single dot in a blanked area to denote sync (see

Figure 4-8). Place the burst vector at 0°, align the burst vec-

tors with the graticule markings, and read the SC/H phase

error as the amount of sync dot offset from the the horizontal

axis. The input signal and the the

EXT REF signal are proper-

ly color framed when the sync dot is within 90° of the burst

vector.

VECTOR PHASE

Figure 4-8. PAL SC/H display.

S C / H R --- Y

SC/H phase can be viewed over a frame of video. Select

WAVEFORM display and FIELD sweep. Enter the FILTER menu

and select

S C / H R --- Y. For NTSC, stable SC/H is a horizontal

line as shown in Figure 4-10. (Figure 4-9 shows the same

display with a

LINE sweep selected.) A sample SC/H phase

error is shown in Figure 4-11. The flat lines indicate that

SC/H phase is stable over the entire frame. For PAL, SC/H is

a sine wave resulting from the 25 Hz offset (Figure 4-12).

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Tektronix 1740A/1750A Instrukcja Użytkownika Strona 93