Agilent Technologies 856290216 Digital Signature Analysis DSA, Display Problems, Line Generators

Digital Signature Analysis (DSA)

Digital signature analysis (DSA) places microprocessor, A2U1, in a simplified known state. This simplified state consists of placing a one-word instruction, MOVE QUICK, (0111

x x 1 0 x x x x XXXO) on the data bus. The microprocessor cycles through its address range continually reading the instruction. Perform the following DSA procedure to test the operation of microprocessor, A2U 1:

1.Press (LINE) to turn the spectrum analyzer off.

2.Move the DSA jumper on J3 (1ocated in the middle of the A2 assembly) from the DISable position to the ENAble position.

3.Remove jumper A2El. A2El is a 16 pin dual-in-line package located in the middle of the A2 Assembly. Press (LINE) to turn the spectrum analyzer on.

4.Use an oscilloscope to confirm that address lines, address strobe, and chip selects are toggling at proper levels.

5.Use an oscilloscope to check the address line sequencing. The signal on each line (starting with Al and ending with A23) should be one-half the frequency of the previous line.

6.If step 4 reveals problems, microprocessor A2Ul is probably faulty.

7.Press (LINE) to turn the spectrum analyzer off. Replace jumper A2El. Move the DSA jumper from connecting E5 and E6 back to connecting E6 and E7.

Display Problems

Line Generators

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 line generators convert the digital display information to an analog output suitable to drive the Al7 CRT driver assembly. These circuits change the digital words into vectors, or lines, which move the beam of the CRT. The vectors are each 6 ps long (width of the INTEGRATE pulse) followed by a 1 ~LS SAMPLE pulse. When characters of text are being drawn, the vectors are 3 ps long.

1.On the spectrum analyzer, press (PRESET).

2.On the spectrum analyzer, press ICAL) MORE CRT ADJ PATTIE@. If the display is blank, press the bottom softkey and then the top softkey.

3. Set an oscilloscope to the following settings:

Amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 V/div Sweep time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ms/div Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External

4. Externally trigger the oscilloscope off the signal at A2U207 pin 8 (LBRIGHT).

10-4 Controller Section