Communication techniques – Match each modulation/coding item to a hallmark concept List I A. FM (frequency modulation) B. DM (delta modulation) C. PSK (phase-shift keying) D. PCM (pulse-code modulation) List II Slope-overload (quantizer step too small for signal slope) μ-law (or A-law) companding Envelope detector Capture effect Hilbert transform Matched filter Select the correct mapping.

Introduction / Context:
Different analog and digital communication blocks are associated with classic effects or processing elements. Recognizing these pairings streamlines system design and exam problem solving.

Given Data / Assumptions:

• FM receivers exhibit the capture effect between competing co-channel signals.
• Delta modulation suffers slope-overload when the step size is too small.
• Optimal detection of PSK in AWGN uses a matched filter (or correlator).
• PCM systems commonly employ μ-law (or A-law) companding to improve SNR at low amplitudes.

Concept / Approach:

Map each technique to the best-known “signature” concept: FM ↔ capture effect; DM ↔ slope-overload; PSK ↔ matched filter; PCM ↔ μ-law companding. Envelope detection (AM), Hilbert transform (SSB analytic signals) are distractors here.

Step-by-Step Solution:

Verification / Alternative check:

Standard comms texts (e.g., Proakis) note matched filtering as the optimum linear receiver for PSK and companding for PCM telephony, while FM capture is a classic broadcast phenomenon.

Why Other Options Are Wrong:

Envelope detection applies to AM, not PSK or FM; Hilbert transform relates to SSB/analytic signals, not FM/PCM core behavior.

Common Pitfalls:

Confusing delta modulation with PCM quantization effects; mixing AM-specific blocks with PSK detection.

Final Answer:

A-4, B-1, C-6, D-2.