Full Rate or FR or GSM-FR was the first digital speech coding standard used in GSM digital mobile phone system. Speech coding is the application of Data compression of Digital audio signals containing Speech. GSM ( Global System for Mobile communications: originally from Groupe Spécial Mobile) is the most popular standard for Mobile phones in the The bit rate of the codec is 13 kbit/s. The quality of the coded speech is quite poor by modern standards, but at the time of development (early 1990s) it was a good compromise between computational complexity and quality. The codec is still widely used in networks around the world. Gradually FR will be replaced by Enhanced Full Rate (EFR) and Adaptive Multi-Rate (AMR) standards, which provide much higher speech quality with lower bit rate. Enhanced Full Rate or EFR or GSM-EFR is a speech coding standard that was developed in order to improve the quite poor quality of GSM - Full Adaptive Multi-Rate (AMR is an Audio data compression scheme optimized for Speech coding.
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Technology
GSM-FR is specified in ETSI 06. The European Telecommunications Standards Institute ( ETSI) is an independent non-for-profit Standardization organization of the Telecommunications 10 and is based on RPE-LTP (Regular Pulse Excitation - Long Term Prediction) speech coding paradigm. Like many other speech codecs, linear prediction is used in the synthesis filter. Linear prediction is a mathematical operation where future values of a discrete-time signal are estimated as a linear function of previous samples However, unlike most modern speech codecs, the order of the linear prediction is only 8. In modern narrowband speech codecs the order is usually 10 and in wideband speech codecs the order is usually 16. Narrowband refers to a situation in radio communications where the bandwidth of the message does not significantly exceed the channel's Coherence bandwidth. In communications, wideband is a relative term used to describe a wide range of frequencies in a Spectrum.
Implementations
The free libgsm codec can encode and decode GSM Full Rate audio.
See also
External links
Half Rate or HR or GSM-HR is a Speech encoding system for GSM developed in the early 1990s Enhanced Full Rate or EFR or GSM-EFR is a speech coding standard that was developed in order to improve the quite poor quality of GSM - Full Adaptive Multi-Rate (AMR is an Audio data compression scheme optimized for Speech coding.Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic