毕业设计（论文）-高保真拾音器设计.docVIP

************学士学位论文（设计）  PAGE 43 高保真拾音器设计 摘要：本文以基于HUSH电路制造的先进的音频降噪芯片SSM2000为核心，设计了一个高保真拾音器系统。通过麦克风拾音电路对混合声音信号进行采集，将采集到的混合声音信号转换成音频信号，经SSM2000的左右音频通道送入芯片，并对音频信号进行降噪处理，当输入的音频信号被处理后，即可提取所需要的信号和噪声的频率分布、幅度信息进行分析。左右声道送入的音频信号经过压控低通滤波器滤波（VCF），再经压控放大器（VCA）放大后输出。滤波器和放大器都是低失真的，而且由它们引起的噪声是可以忽略的。压控滤波器的截止频率可在1KHz到35KHz之间根据需要予以设定。VCA可被设定为衰减或放大，这可增加SSM2000 的灵活性。使用合适的控制电路可以得到合适的控制信号，并施加到VCF和VCA上， 这样可在对信号造成最小损失的同时实现多达25dB的噪声抑制。最后将降噪后的音频信号通过外接功放将其还原成声音信号。 关键词： SSM2000；高保真；麦克风；滤波器；放大器 Design of High-fidelity Pickup Abstract：A high-fidelity pickup system based on audio noise reduction chip SSM2000 fabricated by HUSH circuit is designed in this graduation project. Through a microphone pickup circuit for mixed voice signal acquisition, mixed sound signals will be changed into audio signals, sent into chip through the left and right audio channels of the SSM2000 chip and be processed for noise reduction. When the input audio signal is processed, required signal and noise frequency distribution, range of information can be extracted for analysis. Audio signal sent into left and right channels can be amplified putting out through voltage-controlled low-pass filter (VCF), and then the voltage-controlled amplifier (VCA). Filters and amplifiers are low distortion, and noise caused by them can be negligible. Voltage-controlled filter cutoff frequency can be set as needed between 1KHz to 35KHz. VCA can be set for the attenuation or amplification, which can increase the SSM2000 flexibility. A suitable control signal is available with appropriate control circuit and applied to the VCF and VCA, which can result in minimum loss of signal while achieving up to 25dB of noise suppression. Finally, the denoised signal can be restored to the sound signal through an external audio amplifier. Key words：SSM2000; Fidelity; Microphone; Filter; Amplifier 目 录  TOC \o 1-3 \f \h \z \u  HYPERLINK \l _Toc312206104 第1章 绪论  PAGEREF _Toc312206104 \h 1  HYPERLINK \l _Toc312206105 1.1 研究该课题的背景及意义  PAGEREF _