Takashi Itoh’s scientific contributions

What is this page?


This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.

Publications (1)


A LONG PLAY DIGITAL AUDIO DISC SYSTEM
  • Article

January 1979

·

13 Reads

·

11 Citations

Toshi Tada Doi

·

Takashi Itoh

·

Hiroshi Ogawa

The development of video disk systems has made long-play digital (PCM) audio disk systems possible. The bandwidth required for the two channels of digital audio signals is less than that of video signals which combined with reduction of speed, makes longer playing time possible. For further improvement in packing density, a kind of run-length-limited code is adopted. The code is known as 3PM (three-position modulation), and the packing density can attain 150% of MFM coding for the same minimum wavelength to be recorded. This is achieved at the expense of decreasing jitter margin, which is relatively easy to adjust for in optical disk systems. The resulting playing time is 2 one-half hours for one side of an optical disk with a diameter of 303 mm. The sampling rate is 44. 056 kHz and each of the two channels is coded by 16-bit linear quantization. Revolution rate is 450 r/min. Code errors are analyzed for 1800, 900, and 450 r/min for bit error rate and bit error correlation coefficient. An effective error-correcting scheme called ″cross interleave″ has been developed which makes decoding possible using various types of decoder from a simple erasure type to the complex ″crossword″ type while maintaining full compatibility.