HP 8568B manual Location of Analog-To-Digital Converter Adjustments

23. Analog-To-Digital Converter Adjustments

Procedure 1. Position instrument upright as shown in Figure 3-85 and remove top cover.

2. Set LINE switch to ON and press ~NSTR PRESET).

Standard Procedure 3. Procedure using Low-Noise DC Supply is illustrated in Figure 3-93.

a. Key in [BLANK) TRACE A and SWEEP [S’NGLE].

b. Disconnect cable 0 (black) from sweep ramp input A3A8Jl.

c. Short A3A8TP4 to A3A8TP5 or connect SMB snap-on short to A3A8J 1.

d. Connect the oscilloscope’s 1O:l probe to A3A8TPll and ground the probe’s ground to the A3 section’s card cage.

e. Set the oscilloscope settings as follows:

amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . 0.1 V/div time scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..5.0~s coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..dc

f. Adjust A3A8R6 OFFS for a square wave displayed on the oscilloscope. The square wave should be approximately 4 Vp-p. See Figure 3-86 for location of adjustment.

A3A8

A N A L O G - T O - D I G I T A L C O N V E R T E R

( B e n e a t h C o v e r )

R5	RE
G A I N	O F F S

Figure 3-86.

Location of Analog-To-Digital Converter Adjustments

g. Remove short from A3A8TP4 and A3A8TP5 or disconnect the SMB snap-on short from A3A8Jl.

h.Press (INSTR PRESET).

i.Press MARKER c-1, 1498 (MHz), and CSHIFT) (SINGLE) “.

j.Connect DVM to A3A8TP5 and ground to A3A8TP4. Set DVM

for V de.

k. Connect output of the Low-Noise DC Supply to A3A8Jl. Adjust the Low-Noise DC Supply for DVM indication of + 10.000 &.OOlV dc.

3.140 Adjustments