Observing ripple-counter decode glitches on an oscilloscope A glitch on a decoded output of a ripple counter is often hard to see on a scope primarily because ________.

Introduction / Context:
Ripple counters produce short-lived hazards on decoded outputs when multiple bits transition non-simultaneously. Capturing these glitches on an oscilloscope can be challenging. Understanding why helps in choosing measurement techniques and in designing mitigation strategies.

Given Data / Assumptions:

• We are observing a decoded node driven by combinational logic from ripple counter outputs.
• During state changes, intermediate codes can assert unintended outputs briefly.
• Oscilloscope persistence and bandwidth affect visibility of narrow pulses.

Concept / Approach:
The glitches arise due to propagation delay differences and are typically only a few nanoseconds wide (depending on technology). Such brief events have low energy and can be missed without adequate bandwidth, sample rate, or triggering. While decode glitches occur predictably at transitions, their brevity is the primary reason they are hard to see.

Step-by-Step Solution:
Recognize that hazard pulses are narrow in time.Realize that a scope needs sufficient bandwidth and proper edge triggering on the decoded node to capture them.Conclude that short duration (very fast) is the key difficulty.

Verification / Alternative check:
Using a high-bandwidth scope with infinite persistence or a glitch capture mode reveals the pulses more readily. A logic analyzer with glitch detection can also help.

Why Other Options Are Wrong:
Glitches are not random; they correlate with count transitions. They are indeed less frequent than the steady output, but frequency alone does not prevent viewing; the real obstacle is pulse width (speed). “All of the above” is incorrect because “random” is false.

Common Pitfalls:
Insufficient timebase or trigger settings; probing with excessive capacitance that masks high-speed content.

Final Answer:
it is very fast