In pulse and timing measurements, the rise time of a digital pulse is normally measured between which reference levels?

Introduction:
Rise time characterizes how quickly a signal transitions from LOW to HIGH. Consistent reference levels avoid distortion from overshoot, noise, and edge rounding across technologies.

Given Data / Assumptions:

• We need the conventional measurement points for rise time on a single transition.
• Assume a monotonic leading edge with possible overshoot or rounding.

Concept / Approach:
Industry convention defines rise time as the interval between when the waveform first crosses 10% of its final value and when it first crosses 90% of its final value. This avoids sensitivity to baseline noise near 0% and to final settling near 100%.

Step-by-Step Solution:

Verification / Alternative check:
Some instruments allow 20–80% as an alternative, but 10–90% is the canonical definition used for datasheets and comparisons.

Why Other Options Are Wrong:

• 0 and 100%: Too sensitive to noise and settling behavior.
• 30% and 70%: Non-standard; sometimes used in specific contexts but not the primary convention.
• 50% to 50% (leading to trailing): That is pulse width, not rise time.

Common Pitfalls:
Confusing rise time with propagation delay or pulse width; always check which metric and thresholds are specified.

Final Answer:
10% and 90% level