android 设备返回到 PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND 和 PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND 有什么特点
What features does an android device returing true to PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND and PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND have
我查看了 Android API 文档，在 AudioManager 页面中我发现了以下属性。
PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND (Added in API level 23)
String PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND
Used as a key for getProperty(String) to determine if the default microphone audio source supports near-ultrasound frequencies (range of 18 - 21 kHz).
PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND (Added in API level 23)
String PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND
Used as a key for getProperty(String) to determine if the default speaker audio path supports near-ultrasound frequencies (range of 18 - 21 kHz).
我想知道 "supports near-ultrasound frequencies"
的技术含义是什么
我在 Android 7.0 兼容性定义文档中找到了它
7.8.3。近超声
近超声音频是 18.5 kHz 至 20 kHz 频段。设备实现必须通过 AudioManager.getProperty API 正确报告对近超声音频功能的支持，如下所示：
If PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND is "true", then the following requirements must be met by the VOICE_RECOGNITION and UNPROCESSED audio sources:
The microphone's mean power response in the 18.5 kHz to 20 kHz band MUST be no more than 15 dB below the response at 2 kHz.
The microphone's unweighted signal to noise ratio over 18.5 kHz to 20 kHz for a 19 kHz tone at -26 dBFS MUST be no lower than 50 dB.
If PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND is "true", then the speaker's mean response in 18.5 kHz - 20 kHz MUST be no lower than 40 dB below the response at 2 kHz.
支持接近超声波的频率意味着麦克风可以记录 18 - 21 kHz 范围内的声音（引用自您引用的文档。）
我查看了 Android API 文档，在 AudioManager 页面中我发现了以下属性。
PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND (Added in API level 23)
String PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND
Used as a key for getProperty(String) to determine if the default microphone audio source supports near-ultrasound frequencies (range of 18 - 21 kHz).
PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND (Added in API level 23)
String PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND
Used as a key for getProperty(String) to determine if the default speaker audio path supports near-ultrasound frequencies (range of 18 - 21 kHz).
我想知道 "supports near-ultrasound frequencies"
的技术含义是什么我在 Android 7.0 兼容性定义文档中找到了它
7.8.3。近超声
近超声音频是 18.5 kHz 至 20 kHz 频段。设备实现必须通过 AudioManager.getProperty API 正确报告对近超声音频功能的支持，如下所示：
If PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND is "true", then the following requirements must be met by the VOICE_RECOGNITION and UNPROCESSED audio sources:
The microphone's mean power response in the 18.5 kHz to 20 kHz band MUST be no more than 15 dB below the response at 2 kHz.
The microphone's unweighted signal to noise ratio over 18.5 kHz to 20 kHz for a 19 kHz tone at -26 dBFS MUST be no lower than 50 dB.
If PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND is "true", then the speaker's mean response in 18.5 kHz - 20 kHz MUST be no lower than 40 dB below the response at 2 kHz.
支持接近超声波的频率意味着麦克风可以记录 18 - 21 kHz 范围内的声音（引用自您引用的文档。）