Digital delay elements – definition of a multitap delay line What best describes a multitap digital delay line implemented with basic logic and passive components?

Introduction / Context:
Multitap delay lines are used to create multiple well-defined timing references in digital systems (edge shaping, pulse stretching, time-stamping). Knowing their structure helps when analyzing propagation delay and jitter.

Given Data / Assumptions:

• The delay line is “digital” and “multitap.”
• We consider simple gate-level realizations using passives for timing.
• Taps provide intermediate delayed versions of the same signal.

Concept / Approach:
A common discrete implementation chains inverters, each separated by an RC network to create incremental delays. Each node (tap) outputs a progressively delayed replica. Inverters are preferred because they provide restoration, squaring, and predictable propagation; RC networks introduce the controlled time constant. RL versions are uncommon in basic CMOS/TTL design, and using NANDs is unnecessary unless adding gating logic.

Step-by-Step Solution:

Verification / Alternative check:
Timing chains in many app notes show cascaded inverters with RC shaping or controlled delay cells; ECL/CMOS ICs also implement internal variants of this concept.

Why Other Options Are Wrong:

• Inverters with RL: RL is not typical for logic-level delay; inductors are bulky and less predictable on PCBs.
• NAND + RC / NAND + RL: A NAND is not required for pure delay; it adds logic functionality rather than simple timing.

Common Pitfalls:

• Thinking any multi-gate chain is a “multitap” even without RC timing control.
• Assuming inductive elements are common in digital delay blocks; they are not.

Final Answer:
a series of inverter gates with RC circuits between each one