Agilent Technologies 856290216 Switch Driver Waveform Lchar, IO-8 Controller Section

1 0 . 0

V/div

0 . 0 0

v

2 0 . 0

us/div

0 . 0 0 0

s

INTEGRATE

SAMPLE

LCHAR

VECTOR

I

I

II

III

I

I I

I

I

I

I

I

I

I

I

I

I

I

I

SK194

Figure 10-5. Switch Driver Waveform LCHAR

7.All of the DAC inputs should change state two or more times within a 5 ms window. If one or more DAC bits are not working correctly, this will effect the entire display, especially the diagonal lines that go from lower left to upper right. When these lines are drawn, both the X and Y DACs are stepped one count at a time. A “stuck” bit will distort the diagonal in a repetitive manner. The quicker the repetition, the less significant the “stuck” bit. Horizontal distortions apply to the X LINE GENERATOR DAC, while vertical distortions apply to the Y LINE GENERATOR DAC. The DACS have current outputs so they are not readily observable with an oscilloscope. Continue with step 8 to observe the DAC outputs.

8.To break the effect of feedback in the line generators and to observe the output of the DACs, short J201 pin 13 (J201 pin 1) to TP3 (GND) to observe U201 pin 1 and TP2 (U203 pin 1 and TPl.) Continue with step 9.

9.Set an oscilloscope to the following settings:

Amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 V/div Sweep time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..lms/div Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..AC Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..External

10.Trigger the oscilloscope on the signal at U207 pin 8 (LBRIGHT).

11.The following waveforms should look like Figure 10-6 on the oscilloscope. The top two traces are for the X line generator and the bottom two traces for the Y line generator.

X line generator

U201 pin 1

TP2

Y line generator

U203 pin 1

TPl

IO-8 Controller Section