Question: In a 3GPP-compliant terminal equipment for Adaptive Multi-Rate (AMR) speech codec, what are the possible methods to achieve Analogue-to-Digital (A/D) conversion for uniform digital PCM representation?
Option 1: Direct conversion to 16-bit uniform PCM format
Option 2: Conversion to 8-bit A-law or μ-law compounded format, followed by an 8-bit to 13-bit conversion
Option 3: Either direct conversion to 13-bit uniform PCM format, or conversion to 8-bit A-law or μ-law compounded format, based on ITU-T Recommendations G.711, followed by the 8-bit to 13-bit conversion
Option 4: Only conversion to 16-bit A-law or μ-law compounded format without any further bit-depth conversion
Explanation: This option correctly outlines the two permissible methods for achieving A/D conversion in terminal equipment as per the provided context: - Direct Conversion: Straight to 13-bit uniform PCM format. - Indirect Conversion: First converting to an 8-bit A-law or μ-law format (as specified by ITU-T G.711) and then converting that to a 13-bit representation, as detailed in the clause referenced in the context. This ensures compatibility with both direct and indirect conversion methodologies for achieving the desired digital representation.