具有混音功能的新型语音卡设计与实现

为满足某控制系统实时记录语音和播放录音的实际需求,基于语音压缩编码技术,以现场可编程门阵列(FPGA)为控制核心,设计实现了16个通道采集语音信号,进行ADPCM编码,将语音文件以WAVE格式存储,集监听、播放指定语音通道及任意时间段录音于一体的紧凑型PCI(CPCI)板卡。该板卡区别于传统语音卡的创新点在于运用语音叠加技术使板卡具有混音功能,能够将不同通道语音混音、记录存储,同时具有压缩比可自由选择的功能。详细介绍了板卡的组成机构、工作原理、硬件设计和软件设计。最后进行实验测试,板卡语音存储、语音回放等各项功能正常,音质良好,验证了设计方案的可行性与实用性。

Design and Implementation of the New Voice Card with the functions of Audio Mixing

In order to meet the requirements of real-time recording voice and playback in a certain control system, a kind of voice card is designed based on the speech compressed coding, in which FPGA act as the control core. The design realizes 16 channels to collect speech signal which will be coded with ADPCM, and then the voice data will be stored with WAVE format. This compact PCI card can monitor and play any records in specified channel and time period. Compared with the traditional voice card, the innovative point of our design is that the card has the function of audio mixing by applying overlap-adding (OLA) technique. The card not only can record the mixing voice from different channels but also can free to choose the compression ratio. The card structure, working principle and the design of hardware and software are described in detail. Finally, the experiments show that the function of storing voice and playback are in good condition, and the quality of voice is good. These experimental results obviously confirm the feasibility and practicability of our design.