March 96, from the digest of technical papers of the 1996 IEEE ICCE: 0-7803-3029
Abstract: We have developed a high-performance small-sized transcriber which enables us to record or transcribe a maximum of 48 hours of voice in addition to enjoying playback of hi-fi audio sound on a MiniDisc.
MD is a good potential replacement, however in its standard form it has a maximum capacity of only 148 minutes of audio.
Therefore, this new type of transcriber was developed which has all the portability and quick access benefits of MD, but which can also record up to 48 hours of voice on a single disc.
|Block Diagram of Transcriber
The RF AMP + ADIP (Address In Pre-groove Demodulator) + LPC (Laser Power Control) block was already available from previous development work, and in this project the ENC/DEC + SPP (Shock Proof Processor) and Interface + Memory Controller units were developed.
ENC/DEC + SPP: This is an LSI circuit that encodes and decodes the EFM signal and controls the Shock Proof Memory RAM. This is accomplished directly in hardware, which reduces the software load. The SPP data format is suitable for the ATRAC decoder and the Voice Codec.
Interface + Memory Controller: This unit is an FPGA (field programmable gate-array) that controls the data flow for both audio and voice, or the external Static-RAM so as to extend the interval over which recording can occur without the intervention of the micro-computer. The Interface carries out the detection and management of data errors.
On playback the transcriber automatically selects the ATRAC decoder or the Voice Codec based on the data contents of the disc. It can also playback voice coded audio at 1.6X normal speed without changing voice pitch.
|Rec/Play Time (per disc)
|9, 18, 36,48 hours (selectable)
|Voice Coding Format
|Modified Sub Band Coding (MSBC)
|Audio Coding Format
|Audio MD, MD-Data
|Voice Play Speed
Simple Fast (x1.3, x1.6, x2.0)
Simple Slow (x0.8, x0.9)
Voice Speed Converting
|Erase, Combine, Divide, Move
|Voice Operated Recording, Back Repeat, Title Editing