A 9.6 kb/s speech coder using the Bell laboratories DSP integrated circuit

Crochiere, R.; Cox, R.V.; Johnston, James D.; Seltzer, Linda A.

doi:10.1109/icassp.1982.1171414

Cited by 7 publications

(5 citation statements)

References 9 publications

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“…In this paper we discuss a real-time implementation of the TDHS algorithm based on the Bell Laboratories DSP integrated circuit. It is one component of a 9.6 kbit/s real-time speech coder discussed elsewhere [3], [4]. We also show that the realization of the TDHS algorithm can be accomplished with a minimum buffer size that is twice the maximum pitch period.…”

Section: Introductionmentioning

confidence: 75%

“…This system can be combined with a variety of coders in order to obtain different approaches to low bit rate speech coding [2]. Specifically, it has been used with subband coding for a real-time speech coder at 9.6 kbits/s [ 3 ] . It also has potential for use in speech enhancement systems [5].…”

Section: Discussionmentioning

confidence: 99%

“…In turn this means that input points will be used more than once. The formula for the window is similar to (3) and is given by…”

Section: A Mathematical Description and Buffer Sizesmentioning

confidence: 99%

“…For compression the input data are already in mu-law format. For expansion the input data is linear [3] . The other two subroutinesare used for reading data from high and low memory, respectively.…”

Section: Implementation Of the Shift Register Model Of Tdhs On Thementioning

confidence: 99%

“…This is because mod 120 arithmetic cannot be performed with I , J , or K registers, i.e., pointers ZX1, ZX2, and OFF are kept in regular RAM memory rather than using I , J, and K [8] . The pitch detector algorithm described in this paper was implemented as part of the 9.6 kbit/s speech coder using TDHS [3], but its applicability is not limited to TDHS. Other potential applications for the pitch/periodicity detector are in pitch predicting implementations of adaptive predictive coders [8] and subband coders [,13], as well as in other applications involving harmonic scaling…”

Section: Implementation Of the Shift Register Model Of Tdhs On Thementioning

confidence: 99%

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Real-time implementation of time domain harmonic scaling of speech for rate modification and coding

Cox¹,

Crochiere²,

Johnston³

1983

IEEE Trans. Acoust., Speech, Signal Process.

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Time domain harmonic scaling (TDHS) has been realized in real time on the Bell Laboratories digital signal processing (DSP) integrated circuit. It is an algorithm that can expand or compress the bandwidth and sampling rate of speech by taking advantage of the pitch structure in the speech signal. As such it is useful in a variety of speech applications including speech coding, speech enhancement, and rate modification. A single DSP can perform compression and a second DSP can perform expansion. Both operations require pitch information to be supplied with the input speech. Included in the system is a real-time pitch/periodicity detector which has also been implemented on a single DSP. Its design is based on a novel modification of the autocorrelation function type pitch detector. This paper presents details of both the TDHS and pitch detector implementation and discusses their performances. In particular in this paper we discuss a 2: 1 compression and expansion system that has been used as part of a 9.6 kbit/s speech coder. TDHS was previously thought to require a much larger buffer than the RAM memory available in the DSP. We show that for all the compression/expansion ratios of interest the buffer size needed is twice the maximum pitch period.

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Section: Introductionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 99%

“…In turn this means that input points will be used more than once. The formula for the window is similar to (3) and is given by…”

Section: A Mathematical Description and Buffer Sizesmentioning

confidence: 99%

Section: Implementation Of the Shift Register Model Of Tdhs On Thementioning

confidence: 99%

Section: Implementation Of the Shift Register Model Of Tdhs On Thementioning

confidence: 99%