Multiplexed display technique: is the commonly used method in multiplexed LED/LCD displays called time-division multiplexing (periodic scanning of digits/segments) rather than “time-division modulation”?

Introduction / Context:
Driving multiple display digits efficiently often uses a multiplexed scheme: activate one digit at a time but cycle through them fast enough that human persistence of vision perceives all as continuously lit. The accepted engineering term is time-division multiplexing (TDM), not “time-division modulation.” This question clarifies terminology to reduce confusion in documentation and design discussions.

Given Data / Assumptions:

• Display comprises multiple digits/segments sharing segment lines with separate digit enables.
• Controller scans digits rapidly with suitable duty cycle.
• Brightness is controlled by duty cycle or per-segment PWM, not by changing the data meaning.

Concept / Approach:
Multiplexing is the practice of sharing a resource (segment lines) across multiple channels (digits) by allocating time slots. In display systems, each digit is given a small time window where its enable is asserted and the segment data is presented; the process repeats round-robin. While brightness control can use pulse-width modulation, the overarching mechanism is time-division multiplexing, not modulation of a carrier signal. Therefore, “time-division modulation” is imprecise for this context.

Step-by-Step Solution:

Verification / Alternative check:
MCU and driver IC app notes (MAX7219, HT16K33, TM1637) describe scanning as “multiplexed display driving” using TDM principles and optional PWM for brightness.

Why Other Options Are Wrong:
“Time-division modulation” suggests a modulation scheme; the display technique is resource sharing in time, i.e., multiplexing.
Limiting to LCDs or a fixed duty cycle is incorrect; LEDs and LCDs both use multiplexing with varied duty cycles.

Common Pitfalls:
Equating PWM brightness control with the multiplexing principle; using imprecise language that confuses modulation with multiplexing.

Final Answer:
Applies (time-division multiplexing is the standard term)