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TechSpec
  • Foreword
  • 1 Scope
  • 2 References
  • 3 Definitions, symbols and abbreviations
  • 4 Functional description of the GSM half rate speech codec
    • 4 Functional description of the GSM half rate speech codec
    • 4.1 GSM half rate speech encoder
      • 4.1 GSM half rate speech encoder
      • 4.1.1 High-pass filter
      • 4.1.2 Segmentation
      • 4.1.3 Fixed Point Lattice Technique (FLAT)
      • 4.1.4 Spectral quantization
      • 4.1.5 Frame energy calculation and quantization
      • 4.1.6 Soft interpolation of the spectral parameters
      • 4.1.7 Spectral noise weighting filter coefficients
      • 4.1.8 Long Term Predictor lag determination
      • 4.1.9 Harmonic noise weighting
      • 4.1.10 Code search algorithm
      • 4.1.11 Multimode gain vector quantization
    • 4.2 GSM half rate speech decoder
  • 5 Homing sequences
  • A.1 Codec parameter description
  • A.2 Basic coder parameters

1 Scope

3GPP46.020Half rate speechHalf rate speech transcodingRelease 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

The present document specifies the speech codec to be used for the GSM half rate channel. It also specifies the test methods to be used to verify that the codec implementation complies with the present document.

The requirements are mandatory for the codec to be used either in GSM Mobile Stations (MS)s or Base Station Systems (BSS)s that utilize the half rate GSM speech traffic channel.