4 . 0 0

V/div

 

2 . 5 0 V

 

2 . 0

u s / d i v

 

9 6 . 0 0

u s

 

 

 

 

 

 

 

 

 

 

 

 

 

I

 

I

I

I

I

I

I

I

I

I

I

 

i nr

 

 

 

\III

 

 

II II

 

 

 

 

U213-13

B L A N K I N G

S K 1 9 3

Figure 10-4. Expanded Blanking Waveforms

Display Jumbled or Trace Off Screen

Refer to function blocks D and I of A2 controller schematic diagram (sheet 1 of 4) in the HP 8560 E-Series Spectrum Analyzer Component Level Information.

The two line generators are identical circuits, so the following steps apply to both. The X generator is referenced below, with Y generator references in parentheses.

1.The voltage at A2U202B pin 7 should measure 10.0 V.

2.Perform steps 1 through 5 of “Line Generators” in this chapter. If the X POS and Y POS waveforms look different from those illustrated in Figure 10-2, check the waveforms at the low-pass filter input (function block E in the component-level information binder).

3.The waveform at the low-pass filter should look like X POS in Figure 10-2 but have an amplitude from 0 V to +5 V.

4.If the waveform in step 3 is incorrect, set an oscilloscope to the following settings:

Amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 V/div Sweep time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20ps/div Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External

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

6.Compare the line-generator input signals at the following test points with those illustrated in Figure 10-5. INTEGRATE and SAMPLE waveforms are replicas of VECTOR except for polarity and amplitude. LCHAR is low when characters are drawn.

INTEGRATE:

Q202

collector

SAMPLE:

Q201

collector

LCHAR:

U207

pin 9

VECTOR:

U213

Pin 9

Controller Section 10-7

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