25.Digital Storage Display Adjustments

20.Connect oscilloscope to A3A3TP7.

21.Adjust A3A2R51 Y S&H BAL for minimum dc offset between the level of the signal inside the two pulses to the signal level outside the two pulses.

22.Set LINE switch to STANDBY.

23.Reinstall A3A3 Line Generator in instrument without extender boards.

24.Set LINE switch to ON.

X and Y Offset and 25. Gain Adjustments 26,

Press (INSTR PRESET).

Key in [FREQUENCY SPAN] 0 Hz, [SWEEP TIME) 100 ps.

27.Disconnect cable 9 (white) from A3A9J2 and connect to A3A2J2 LG/FS test connector on A3A2 Intensity Control; the other end of the cable remains connect connected to A3A2J1.

28.Select TRIGGER [VIDEO] and adjust front-panel LEVEL control for a stable display on instrument CRT.

29.Adjust A3AlR34 SWP OFFSET so that the signal trace begins at the left edge graticule line. Refer to Figure 3-90 for location of adjustment.

30.Adjust A3A3R4 X GAIN for twenty cycles displayed on the CRT graticule. This may be made easier by adjusting A3AlR34 SWP OFFSET so that the first peak is centered on the left edge graticule line, then adjusting A3A3R4 X GAIN for two cycles per division with the twentieth cycle being centered on the right edge graticule line. A3AlR34 SWP OFFSET must then be readjusted so that the trace begins at the left edge graticule line. See Figure 3-90. for location of adjustment.

31.Remove the cable 9 (white) from A3A2J2 LG/FS test connector and reconnect to A3A9J2.

32.Remove cable 7 (violet) from A4AlJl. Short A3A9TPl to A3A9TP3 or connect an SMB snap-on short to A3A9Jl.

33.Connect DVM to A3A9TP3 and DVM ground to A3A9TPl.

34.Press LIN pushbutton.

35.DVM indication should be 0.000 kO.002 V dc.

36.Adjust A3A3R43 YOS to align the bottom graticule line with the fast sweep signal trace.

37.Remove the short between A3A9TPl and A3A9TP3 (or the SMB snap-on short) and reconnect cable 7 (violet) to A4AlJl.

38.Key in [CENTER FREQUENCY) 20 MHz. Connect CAL OUTPUT to RF INPUT. Press LOG (ENTER dB/DIv] 10 dB.

39.Connect the DVM to A4AlTP3 and the DVM ground to the IF casting.

40.Press [REFERENCE LEVEL) and adjust DATA knob and the frontpanel AMPTD CAL adjust for DVM indication of +2.000 50.002 V dc.

3-148 Adjustments