In electronics test and measurement, which single instrument is specifically designed to generate multiple standard waveforms—such as square, triangular, and sawtooth—over a selectable frequency and amplitude range?

Introduction:
A modern laboratory often needs a versatile source capable of producing different periodic waveforms for testing filters, amplifiers, and digital circuits. This question checks recognition of the instrument purpose-built to create common waveforms like sine, square, triangle, and sawtooth with controllable parameters.

Given Data / Assumptions:

• We need one instrument that outputs multiple waveform shapes.
• Output frequency, amplitude, and duty cycle (for square) are typically adjustable.
• Use cases include sweeping circuits under test and stimulating time-domain responses.

Concept / Approach:
A function generator is designed to synthesize several standard functions (waveforms). It commonly provides sine, square, triangle, ramp/sawtooth, and often pulse outputs. Controls typically include frequency, amplitude, DC offset, and duty cycle, making it the correct tool for general-purpose waveform creation.

Step-by-Step Solution:
1) Identify the requirement: multiple waveform shapes (square, triangular, sawtooth).2) Map to instruments: RF generators focus on sine at RF bands; AF generators focus on audio-band sine.3) Frequency meters/counters measure frequency; they do not generate waveforms.4) Only a function generator natively produces the requested set of waveforms.

Verification / Alternative check:
Check front panels of typical bench function generators: waveform-select buttons (sine, square, triangle, ramp), plus knobs/keys for frequency and amplitude, confirm suitability for the stated need.

Why Other Options Are Wrong:
Radio frequency generator: primarily sine at RF; not multi-waveform by default.
Audio frequency generator: primarily sine in the audio band.
Frequency meter/counter: measures frequency; no output generation.
Pulse height analyzer: analyzes pulses; does not generate standard periodic waveforms.

Common Pitfalls:
Assuming any “signal generator” provides all shapes. Many specialize in sine-only outputs; always verify waveform capability.

Final Answer:
a function generator