Performance Tests
4–74 TDS 684A, TDS 744A, & TDS 784A Service Manual
Figure 4–33: 60 Hz Rejection Test Result – TDS 684A Shown
6. Check Line Count Accuracy.
a. Set up oscilloscope for Line Count Accuracy Test.
HPress WAVEFORM OFF.
HPress CH1.
HPress HORIZONTAL MENU.
HPress the main-menu Record Length.
HPress the side-menu –more– until you see the appropriate menu.
HPress the side-menu 5000 points in 100divs.
HPress the main-menu Horiz Scale (/div).
HUse the keypad to set the horizontal scale to 200 ns (press 200,
SHIFT, n, then ENTER).
b. Check Line Count Accuracy.
HConnect a composite output signal from the rear of the PAL signal
source (labeled COMPST on the TSG 121) to the CH1 input
through a 75 W cable and a 75 W terminator. See Figure 4–34.