声学相关词汇_声学词汇

在接触声学知识时候，经常会有一些专有词汇，现记录下来，用于后期查阅。

1. ANC

Active Noise Cancel（主动噪音消除，或称主动降噪），主要功能是：阻止，减少外界声音传入耳朵。（即使在很嘈杂的环境中通话，含有ANC功能的一方可以很清晰听到对方的讲话）

2. ENC

Environmental Noise Cancel（环境噪音消除）

3. AEC

Acoustic Echo Cancel（回音消除）：过滤掉由喇叭声音回传到MIC（咪）的声音。

4. DRC

Dynamic Range Compression（动态范围压缩）：This function of the DRC is to adjust the signal gain in conditions where the input amplitude is unknown or varies over a wide range.

包含的一些参数如下：

• Pregain：pregain(in dB) applied before DRC effects.
• Threshold：a compressor reduces the level of an audio signal if its amplitude exceeds a certain threshold.
• Ratio：the amount of gain reduction is determined by ratio
• Attack Time：time to control how quickly it enables the compression
• Release Time：time to control how quickly it disables the compression

5、AGC

AGC：Automatic Gain Control

6. Level Dependance (Audio/DSP)

A microphone is placed on each cup and their signal is passed through to the corresponding speaker, allowing for situational awareness and ability to communicate with others without needing to remove the device.
For better voice clarity, the microphones signals are filtered, isolating and enhancing human voices while reducing wind noise and high pitched sounds.
Automatic Gain Control is applied to the microphones to protect the user from loud noise, attack time should be lower than 10ms to prevent any damage to the user’s ear
Microphone to speaker passthrough Latency should be lower than 5ms to not disorient the user and keep a natural feeling to the surround sound.

7、Sidetone

Sidetone：侧音，主要是用于over-ear的heasdset，在打电话时候，可以大致知道自己说话声音的amplitude.

8、Limiter

用于A2DP stream，控制音量在指定值以下，比如80dB。

9、Dosimeter

用于A2DP stream，保护听力，防止在大分贝下连续使用过长时间。

10、ALC

ALC：Automatic Level Control

11、A-weight

A加权/计权，一种音频测量的标准权重曲线，用于反映人耳的响应特性，用dBA表示。人耳对于不同频段的声音变化敏感程度不一样，太高或者太低都不敏感，类似正态分布图形，看起来像A字，所以叫A-weight。

12 Loudness

Loudness：响度，音量

13 NRR/SNR

 refered URL：职业健康科普：听力防护产品中的SNR和NRR

NRR：Noise Reduction Rating，降噪率，由美国环境保护组织用于衡量听力保护产品的抗噪性能标准。目前市面上出售的抗噪产品NRR大致在0-40dB范围内。

SNR：Simplied Noise level Reduction，简化的噪声减少率，欧盟对听力防护产品降噪性能测试的标准。