| 摘要 |
A digital sound system for motion picture films employs a digital time code on the film to trigger the transfer of sound data from a digital audio store to a FIFO memory. The digital audio data is read out from the FIFO memory and played back in the theater at a constant rate, with any jumps in the digital time code handled by making a corresponding jump within the digital audio store but not in the FIFO memory. Readout from the FIFO memory and clocking of the digital-to-analog converters (DACs) used for theater playback is synchronized to the AC mains that powers the theater projector, and thus allows for an uninterrupted audio playback even if time code entries on the film are obliterated. The FIFO memory need only have enough capacity to accommodate the maximum audio store access time, and can be quite small. |
