Question: In EVS (Enhanced Voice Services) codec, what approach is utilized for constructing a partial redundant frame specifically for unvoiced frame types (RF_NELP) to handle the wider dynamic range of the TBE gain frame?
Option 1: Adaptive Multi-Rate Wideband (AMR-WB) Coding Scheme
Option 2: Transform Coded Excitation (TCX) with Enhanced Pulse Excitation
Option 3: Low Bit-Rate Noise Excited Linear Prediction (NELP) Coding Scheme
Option 4: Algebraic Code-Excited Linear Prediction (ACELP) for Narrowband
Explanation: The correct answer is Option 3 because, according to EVS codec specifications in unvoiced coding mode, a low bit-rate Noise Excited Linear Prediction (NELP) coding scheme is employed to construct partial redundant frames for unvoiced frame types, preserving the wider dynamic range of the TBE gain frame and ensuring optimal voice quality.