Design of Digital Voice Storage and Playback System

The traditional tape voice recording and reproducing system has many limitations due to its large volume and inconvenient use in the use of electronic and information processing. This paper presents a compact, low-power digital voice storage and playback system will be able to replace it. The basic principle of digital voice storage and playback system is the digital control of voice recording and playback. Among them, the key technology is that in order to increase the voice storage time and improve the utilization of memory, the use of non-distortion compression algorithm to compress the voice signal and then stored in the playback and then decompression while the input voice signal Filtering to suppress noise and interference, thus ensuring the reliable quality of voice playback. The system uses three methods, namely data acquisition, straight sampling, sample sampling and self-similar incremental modulation to complete the storage and playback of voice signals 32.7s, 65.5s and 147.4s respectively. The front straight AGC controls the speech signal within the controllable range of the A / D converter to ensure that the voice signal is not distorted. Bandpass filter a reasonable range effectively, filters out-of-band noise and reduces aliasing distortion. Through the post-level compensation circuit on the output of the voice signal correction, playback voice clear. The system has the functions of automatic recording, manual recording, recording and playing time display and protection of voice signal after power failure.