Chip design of portable speech memopad suitable for persons with visual disabilities

Jhing Fa Wang, Jia Ching Wang, Han Chiang Chen, Tai Lung Chen, Chin Chan Chang, Ming Chi Shih

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


This paper presents the design of a speech recognition and compression chip for portable memopad devices, especially suitable for use by the visually impaired. The proposed chip design is based on several cores of which they can be regarded as intellectual property (IP) cores to be used for a variety of speech-related application systems. A cepstrum extraction core and a dynamic warping core are designed for mapping the speech recognition algorithms. In the cepstrum extraction core, a novel architecture computes the autocorrelation between the overlapping frames using two pairs of shift registers and an intelligent accumulation procedure. The architecture of the dynamic time warping core uses only a single processing element, and is based on our extensive study of the relationship among the nodes in the dynamic time warping lattice. Bit rate is the key factor affecting the memory size for speech compression; therefore, a very low bit-rate speech coder is used. The speech coder exploits a line-spectrum-based interpolation method, which yields fine quality synthesized speech despite the low 1.6 Kbps bit rate. The 1.6 K vocoder core is cost-effective, and it integrates both encoder and decoder algorithms. The proposed design has been tested via hardware simulations on Xilinx Virtex series FPGAs and a semi-custom chip fabricated by 0.35 μm CMOS single-poly-four-metal technology on a die size approximately 4.46 × 4.46 mm2.

Original languageEnglish
Pages (from-to)644-658
Number of pages15
JournalIEEE Transactions on Speech and Audio Processing
Issue number8
StatePublished - Nov 2002


  • Intellectual property (IP)
  • Low bit-rate speech coding
  • Speech compression
  • Speech recognition
  • VLSI
  • Visual disability


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