Question: In the EVS codec, what is the primary purpose of applying perceptually weighted LPC coefficients to the synthesized TCX decoder output during filter memory updates?
Option 1: To enhance formant frequencies in the decoded speech signal
Option 2: To update the synthesis filter states for CELP encoding and residual signal computation
Option 3: To perform global gain decoding in the MDCT domain
Option 4: To apply temporal noise shaping to the decoded spectrum
Explanation: The correct answer highlights the key role of applying perceptually weighted LPC coefficients in updating filter memories, crucial for maintaining accurate synthesis filter states. This ensures both CELP encoding and residual signal computation are based on up-to-date, perceptually relevant filter states, directly impacting encoded voice service quality.