Half Rate
In this article, the topic of Half Rate is addressed from a broad and varied perspective. Half Rate is a topic that has sparked interest and debate in various spheres of society, generating conflicting opinions and divergent positions. Throughout history, Half Rate has played a fundamental role in the evolution of different aspects of daily life, as well as in the development of culture and identity of different communities. Through a detailed and in-depth analysis, the multiple edges that make up the complexity of Half Rate will be explored, examining its impact, implications and possible future projections.
Half Rate (HR or GSM-HR or GSM 06.20) is a speech coding system for GSM, developed in the early 1990s.
Since the codec, operating at 5.6 kbit/s, requires half the bandwidth of the Full Rate codec, network capacity for voice traffic is doubled, at the expense of audio quality. The sampling rate is 8 kHz with resolution 13 bit, frame length 160 samples (20 ms) and subframe length 40 samples (5 ms).
GSM Half Rate is specified in ETSI EN 300 969 (GSM 06.20), and uses a form of the VSELP algorithm. Previous specification was in ETSI ETS 300 581–2, which first edition was published in December 1995.
For some Nokia phones one can configure the use of this codec:
- To activate HR codec use enter the following code: *4720#
- To deactivate HR codec use enter the following code: #4720#
See also
- Full Rate
- Enhanced Full Rate (EFR)
- Adaptive Multi-Rate (AMR)
- Adaptive Multi-Rate Wideband (AMR-WB)
- Extended Adaptive Multi-Rate - Wideband (AMR-WB+)
References
- ^ ETSI, EN 300 969 - Half rate speech transcoding (GSM 06.20 version 8.0.1 Release 1999), Retrieved on 2009-07-11
- ^ ETSI ETS 300 581-2 - Half rate speech transcoding (GSM 06.20 version 4.3.1), Retrieved on 2009-07-11
External links
- ETSI EN 300 969 - Half rate speech transcoding (GSM 06.20 version 8.0.1 Release 1999) - technical specification
- ETSI ETS 300 581-2 - Half rate speech transcoding (GSM 06.20 version 4.3.1) - obsoleted
- 3GPP TS06.20 - technical specification
- RFC 5993 - RTP Payload format for GSM-HR
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