Digital Electronics: Principles, Devices and Applications

Troubleshooting Digital Circuits and Test Equipment 691Ph. Incr.Register(PIR)AdderPhaseAccumulatorRAMDACLPFSythesisedOutputReferenceClockLoadWaveformSamplesFigure 16.32Arbitrary waveform generator architecture.Figure 16.33Arbitrary waveform generator – typical waveform.16.16 Logic ProbeThe logic probe is the most basic tool used for troubleshooting of digital circuits. It is a small, handheldpen-like test instrument with a metallic tip on one end (Fig. 16.34). The instrument can be used toascertain the logic status of various points of interest such as the pins of digital integrated circuits ina digital circuit. The logic status is indicated by a glowing LED. There may typically be three LEDsFigure 16.34Logic probe. Reproduced with permission of Phoronix/Michael J. Larabel.