In pulse and rectangular-wave terminology (e.g., radar or digital timing), which term explicitly expresses the frequency of a rectangular pulse train?

Introduction:
Rectangular waves and pulse trains are described by several timing terms. Correctly distinguishing between frequency, period, and related descriptors is essential in communications, radar, and digital electronics.

Given Data / Assumptions:

• Uniform pulse train with constant spacing between pulses.
• Standard radar/digital nomenclature: PRF and PRT.
• We seek the term that denotes frequency specifically.

Concept / Approach:
PRF stands for Pulse Repetition Frequency, the number of pulses per second. It is the reciprocal of PRT (Pulse Repetition Time), which is the time interval between successive pulses. While Hz is the unit of frequency, PRF is the named parameter used to specify the frequency of a pulse train in context.

Step-by-Step Solution:
Define PRF: PRF = pulses per second = 1 / PRT.Define PRT: the period between pulse starts (seconds).Relate to frequency units: PRF is measured in hertz (Hz).Thus the correct term for pulse frequency is PRF.

Verification / Alternative check:
Datasheets for radar, lidar, and ultrasonic rangefinders list PRF as a key specification for update rate and ambiguity; it always denotes pulses per second, confirming the terminology.

Why Other Options Are Wrong:

• Hz: A unit, not the contextual term; PRF is the named parameter.
• Period: Time quantity, not frequency.
• PRT: Reciprocal of PRF; denotes time, not frequency.
• Duty cycle: Fraction of time the signal is high; independent of PRF for a given pulse width.

Common Pitfalls:

• Confusing units (Hz) with named parameters (PRF).
• Mixing PRF with carrier frequency in pulse-modulated systems; they are distinct.

Final Answer:
PRF