Keithley 2520, Service Manual, Page: 77 / 137

Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4-5
Overall block diagram
Figure 4-1 shows an overall block diagram of the Model 2520. Circuitry may be divided
into two general areas:
• Analog circuits — includes measurement circuits for voltage, and I-V converter for
current, A/D converters, and voltage bias and current source circuits.
• Digital circuits — includes the microcomputer that controls the analog section,
front panel, and GPIB and RS-232 ports, the DSP (digital signal processor), and
associated interfacing and data storage circuits.