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In this paper we address the question of how to extract the non-linearities in speech with the prime purpose of facilitating coding of the residual signal in residual rxcitetl coders. The short-term prediction of speech in speech coders is extensively based on linear models, ‘.g. the Linear Predictive Coding technique (LPC), which is one of the most basic(More)
During the years 1999 and 2000, the Telecommunication Industry Association (TIA) and the 3 Generation Partnership Project 2 (3GPP2), managed a competition and a selection process for a new speech coding standard for CDMA applications. The new speech coding standard, which is coined Selectable Mode Vocoder (SMV), will become a service option in CDMA systems(More)
This paper presents the core technology of novel enhancements to traditional CELP coding, coined eXtended CELP (eX-CELP). It is centered on a combined and selective usage of closed-loop/openloop approach, and variant algorithm structure concept. The above two concepts are complemented by new features and refined existing technologies. The eX-CELP paradigm(More)
This paper presents the 4 kbit/s speech coding candidate submitted by AT&T, Conexant, Deutsche Telekom, France Telecom, Matsushita, and NTT for the ITU-T 4 kbit/s selection phase. The algorithm was developed jointly based on the qualification version of Conexant. This paper focuses on the development carried out during the collaboration in order to narrow(More)
This paper presents a candidate for the ITU-T G.722 packet loss concealment standard. The algorithm is based on waveform extrapolation in the speech domain. The strong backward adaptive nature of G.722 makes the state update during lost frames a challenge. The paper presents methods to update the G.722 subband decoder state memory during packet loss.(More)
This paper describes the BroadVoice® speech coding algorithm, which has been standardized as PacketCable™, SCTE®, and ANSI standards for VoIP cable telephony. The BroadVoice family of codecs includes a 16 kb/s BroadVoice 16 narrowband codec and a 32 kb/s BroadVoice32 wideband codec. BroadVoice is based on two-stage noise feedback coding(More)
This paper describes new efficient Vector Quantization (VQ) techniques that enable low complexity implementations of VQbased Noise Feedback Coding (NFC). These methods offer mathematical equivalence to higher complexity methods. Furthermore, the paper presents efficient codec structures for general noise shaping as used in BroadVoice®16 – a new SCTE®(More)
This paper proposes two techniques to improve packet loss concealment (PLC). In the first technique, time-warping is used to stretch or shrink the time axis of the signal received in the first good frame after frame loss to align it with the extrapolated signal used to conceal the bad frame. This aligning procedure avoids any destructive interference that(More)