Match signals to their typical types: (A) Output of a signal generator, (B) Error signal from a synchro, (C) Output of a JK flip-flop, (D) Signal received by radar — with: (1) Modulated, (2) Digital, (3) Analog, (4) Stochastic (random).

Introduction / Context:
Engineering signals are broadly categorized by structure and randomness: analog vs digital, modulated vs baseband, and deterministic vs stochastic. This question matches common sources to their most representative signal type.

Given Data / Assumptions:

• (A) Signal generator output
• (B) Synchro error signal
• (C) JK flip-flop output
• (D) Radar-received signal
• Types: (1) modulated, (2) digital, (3) analog, (4) stochastic

Concept / Approach:

Laboratory/RF signal generators commonly produce modulated outputs (AM/FM/PM, pulse) in addition to pure tones, so “modulated” captures the general case. Synchros are electromechanical transducers; their error signals are continuous voltages proportional to angular misalignment → analog. A JK flip-flop is a bistable digital device with logic-level output waveforms. Radar returns are random due to thermal noise, clutter, and target fluctuations → stochastic.

Step-by-Step Solution:

Verification / Alternative check:

Datasheets for modern function/RF generators list modulation features; synchro theory defines analog differential voltages; digital logic families define flip-flop outputs; radar detection uses probabilistic models (Swerling, CFAR) grounded in stochastic processes.

Why Other Options Are Wrong:

Labeling the synchro error as modulated misstates its role; calling flip-flop outputs analog contradicts digital operation; radar signals are not purely deterministic.

Common Pitfalls:

Assuming “signal generator” always means a simple sine source; ignoring noise dominance in received RF signals.

Final Answer:

A-1, B-3, C-2, D-4