TI中文支持网Part Number:TLV320AIC3104
您好，
我们用该codec做通话的时候，发现免提那一路的底噪特别大，并且随着通话时间增加，底噪还会越来越大；
目前主要现象如下：
1. 通话的时候就会有比较大的底噪，之后随着通话时间增加，底噪越来越大声；中途一端mute后，底噪就会暂时变小，重新打开后过一段时间，又会变大了。
2. 断开mic（悬空）后也有底噪； 但将mic的正负用电阻接起来，对端就听不到底噪声。
3. 在HAL层打开mic和spk通路，录制音频，再用tinyplay播放，这时候的底噪却很小，几乎听不到。
4. 对mic静音后再打开，对端偶尔会听到电流音（滋滋）。
5. 切换到其他通路时底噪也很小，几乎听不到。
测试时是在语音房测试的，没有其他环境噪音。
麻烦帮忙看一下为什么会产生这么大的底噪呢？
附件中分别是原理图、寄存器、通路path、通话过程dump出来的音频：
原理图：
寄存器：
rk3326_m2g:/ # cat /sys/kernel/debug/regmap/1-0018/registers 00: 00 01: 00 02: 11 03: 10 04: 04 05: 00 06: 00 07: 0a 08: 00 09: 00 0a: 00 0b: 01 0c: 00 0d: 00 0e: 00 0f: 3c 10: 3c 11: ff 12: ff 13: 84 14: 78 15: f8 16: fc 17: 78 18: 80 19: 00 1a: 00 1b: fe 1c: 00 1d: 00 1e: fe 1f: 00 20: 18 21: 18 22: 00 23: 00 24: 00 25: c0 26: 00 27: 00 28: 00 29: 00 2a: 00 2b: 00 2c: 00 2d: 2f 2e: 2f 2f: 2f 30: 00 31: 00 32: 00 33: 85 34: 2f 35: 2f 36: af 37: 00 38: 00 39: 00 3a: 84 3b: 00 3c: 00 3d: 00 3e: 2f 3f: 2f 40: 2f 41: 85 42: 00 43: 00 44: 00 45: 2f 46: 2f 47: af 48: 84 49: 2f 4a: 2f 4b: af 4c: 2f 4d: 2f 4e: af 4f: 09 50: 2f 51: 49 52: 12 53: 00 54: d8 55: 26 56: 89 57: 00 58: 00 59: 92 5a: 2f 5b: 49 5c: 92 5d: 89 5e: 00 5f: 00 60: 00 61: 00 62: 00 63: 00 64: 00 65: 01 66: 02 67: 00 68: 00 69: 00 6a: 00 6b: 00 6c: 00 6d: 00
rk3326_m2g:/ # tinymix Mixer name: 'rockchip,tlv320aic3x-codec' Number of controls: 117 ctltypenumnamevalue 0INT1Left Line Mixer Line2R Bypass Volume118 1INT1Right Line Mixer Line2L Bypass Volume118 2INT1Left HP Mixer Line2R Bypass Volume118 3INT1Right HP Mixer Line2L Bypass Volume118 4INT1Left HPCOM Mixer Line2R Bypass Volume118 5INT1Right HPCOM Mixer Line2L Bypass Volume118 6INT2Line Line2 Bypass Volume71 71 7INT2HP Line2 Bypass Volume71 71 8INT2HPCOM Line2 Bypass Volume71 71 9INT2Mono Line2 Bypass Volume71 71 10INT2Mono PGA Bypass Volume71 71 11INT2Mono DAC Playback Volume71 71 12BOOL1Mono Playback SwitchOn 13INT2PCM Playback Volume127 127 14INT1Left Line Mixer PGAR Bypass Volume30 15INT1Left Line Mixer DACR1 Playback Volume80 16INT1Right Line Mixer PGAL Bypass Volume118 17INT1Right Line Mixer DACL1 Playback Volume100 18INT1Left HP Mixer PGAR Bypass Volume118 19INT1Left HP Mixer DACR1 Playback Volume118 20INT1Right HP Mixer PGAL Bypass Volume118 21INT1Right HP Mixer DACL1 Playback Volume118 22INT1Left HPCOM Mixer PGAR Bypass Volume118 23INT1Left HPCOM Mixer DACR1 Playback Volume118 24INT1Right HPCOM Mixer PGAL Bypass Volume118 25INT1Right HPCOM Mixer DACL1 Playback Volume 118 26INT2Line PGA Bypass Volume45 45 27INT2Line DAC Playback Volume100 100 28INT2HP PGA Bypass Volume71 71 29INT2HP DAC Playback Volume71 71 30INT2HPCOM PGA Bypass Volume71 71 31INT2HPCOM DAC Playback Volume71 71 32BOOL2Line Playback SwitchOn On 33BOOL2HP Playback SwitchOff Off 34BOOL2HPCOM Playback SwitchOff Off 35BOOL2AGC SwitchOff Off 36ENUM1Left AGC Target level-5.5dB 37ENUM1Right AGC Target level-5.5dB 38ENUM1Left AGC Attack time8ms 39ENUM1Right AGC Attack time8ms 40ENUM1Left AGC Decay time100ms 41ENUM1Right AGC Decay time100ms 42ENUM1Headset Handset Input Switchon 43ENUM1Handset Spk En Switchon 44ENUM1Handset Fix Spk Pop Switchon 45ENUM1Handfree Spk En Switchon 46BOOL2De-emphasis SwitchOff Off 47INT2PGA Capture Volume60 60 48BOOL2PGA Capture SwitchOn On 49ENUM2ADC HPF Cut-offDisabled Disabled 50ENUM1Output Driver Power-On time0us 51ENUM1Output Driver Ramp-up step0ms 52BYTE128ELD00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 53INT1AUDIO MODE0 54INT1AUDIO MUTE1 55ENUM1Left DAC MuxDAC_L1 56ENUM1Left HPCOM Muxdifferential of HPLOUT 57ENUM1Right DAC MuxDAC_R1 58ENUM1Right HPCOM Muxdifferential of HPROUT 59ENUM1Left Line1L Muxdifferential 60ENUM1Left Line1R Muxdifferential 61ENUM1Right Line1L Muxdifferential 62ENUM1Right Line1R Muxdifferential 63BOOL1Left PGA Mixer Line1L SwitchOn 64BOOL1Left PGA Mixer Line1R SwitchOff 65BOOL1Left PGA Mixer Line2L SwitchOff 66BOOL1Left PGA Mixer Mic3L SwitchOff 67BOOL1Left PGA Mixer Mic3R SwitchOff 68ENUM1Left Line2L Muxsingle-ended 69BOOL1Right PGA Mixer Line1R SwitchOff 70BOOL1Right PGA Mixer Line1L SwitchOn 71BOOL1Right PGA Mixer Line2R SwitchOff 72BOOL1Right PGA Mixer Mic3L SwitchOff 73BOOL1Right PGA Mixer Mic3R SwitchOff 74ENUM1Right Line2R Muxsingle-ended 75BOOL1Left Line Mixer PGAL Bypass SwitchOff 76BOOL1Left Line Mixer DACL1 SwitchOff 77BOOL1Left Line Mixer PGAR Bypass SwitchOn 78BOOL1Left Line Mixer DACR1 SwitchOff 79BOOL1Left Line Mixer Line2L Bypass SwitchOff 80BOOL1Left Line Mixer Line2R Bypass SwitchOff 81BOOL1Right Line Mixer PGAL Bypass SwitchOff 82BOOL1Right Line Mixer DACL1 SwitchOn 83BOOL1Right Line Mixer PGAR Bypass SwitchOff 84BOOL1Right Line Mixer DACR1 SwitchOn 85BOOL1Right Line Mixer Line2L Bypass SwitchOff 86BOOL1Right Line Mixer Line2R Bypass SwitchOff 87BOOL1Left HP Mixer PGAL Bypass SwitchOff 88BOOL1Left HP Mixer DACL1 SwitchOff 89BOOL1Left HP Mixer PGAR Bypass SwitchOff 90BOOL1Left HP Mixer DACR1 SwitchOff 91BOOL1Left HP Mixer Line2L Bypass SwitchOff 92BOOL1Left HP Mixer Line2R Bypass SwitchOff 93BOOL1Right HP Mixer PGAL Bypass SwitchOff 94BOOL1Right HP Mixer DACL1 SwitchOff 95BOOL1Right HP Mixer PGAR Bypass SwitchOff 96BOOL1Right HP Mixer DACR1 SwitchOff 97BOOL1Right HP Mixer Line2L Bypass SwitchOff 98BOOL1Right HP Mixer Line2R Bypass SwitchOff 99BOOL1Left HPCOM Mixer PGAL Bypass SwitchOff 100BOOL1Left HPCOM Mixer DACL1 SwitchOn 101BOOL1Left HPCOM Mixer PGAR Bypass SwitchOff 102BOOL1Left HPCOM Mixer DACR1 SwitchOff 103BOOL1Left HPCOM Mixer Line2L Bypass SwitchOff 104BOOL1Left HPCOM Mixer Line2R Bypass SwitchOff 105BOOL1Right HPCOM Mixer PGAL Bypass SwitchOff 106BOOL1Right HPCOM Mixer DACL1 SwitchOff 107BOOL1Right HPCOM Mixer PGAR Bypass SwitchOff 108BOOL1Right HPCOM Mixer DACR1 SwitchOn 109BOOL1Right HPCOM Mixer Line2L Bypass SwitchOff 110BOOL1Right HPCOM Mixer Line2R Bypass SwitchOff 111BOOL1Mono Mixer Line2L Bypass SwitchOff 112BOOL1Mono Mixer PGAL Bypass SwitchOff 113BOOL1Mono Mixer DACL1 SwitchOn 114BOOL1Mono Mixer Line2R Bypass SwitchOff 115BOOL1Mono Mixer PGAR Bypass SwitchOff 116BOOL1Mono Mixer DACR1 SwitchOn
免提MIC和SPK通路：
SPK:
tinymix "PCM Playback Volume" 127
tinymix "Line DAC Playback Volume" 100
tinymix "Right Line Mixer DACL1 Playback Volume" 100
tinymix "Right Line Mixer DACL1 Switch" 1
tinymix "Right Line Mixer DACR1 Switch" 1
tinymix "Line Playback Switch" 1
tinymix "Handfree Spk En Switch" 1
MIC:
tinymix "PGA Capture Volume" 60
tinymix "Left PGA Mixer Line1R Switch" 0
tinymix "Right PGA Mixer Line1R Switch" 0
tinymix "Left PGA Mixer Line1L Switch" 1
tinymix "Right PGA Mixer Line1L Switch" 1
tinymix "PGA Capture Switch" 1
tinymix "Left Line1L Mux" 1
tinymix "Left Line1R Mux" 1
tinymix "Right Line1L Mux" 1
tinymix "Right Line1R Mux" 1
dump出来的音频：
本地MIC通话时录制的音频：
单击此处播放此音频剪辑
(function(id)
{
var v = document.getElementById(id);var op = v.style.position, ol = v.style.left, or = v.style.right, fe = [],
checkVideo = function() {
if (!v.canPlayType || v.error) {
while (v.childNodes.length > 0) {
v.parentNode.insertBefore(v.childNodes[0], v);
}
v.parentNode.removeChild(v);
} else if (v.readyState == 0) {
window.setTimeout(checkVideo, 249);
}
},
checkVideoRendered = function() {
if (v.networkState == 1 && v.readyState == 4) {
v.style.position = op;
v.style.left = ol;
v.style.right = or;
for (var i = 0; i < fe.length; i++) {
fe[i].parentNode.removeChild(fe[i]);
}
} else {
window.setTimeout(checkVideoRendered, 249);
}
}
if (navigator.userAgent.indexOf('iPad') == -1 && navigator.userAgent.indexOf('iPhone') == -1 && navigator.userAgent.indexOf('iPod') == -1) {
window.setTimeout(checkVideo, 249);
}
})('a_981866f17b4c4be1beca5bb8e0e6a4a6');
对端送过来的音频：
单击此处播放此音频剪辑
(function(id)
{
var v = document.getElementById(id);var op = v.style.position, ol = v.style.left, or = v.style.right, fe = [],
checkVideo = function() {
if (!v.canPlayType || v.error) {
while (v.childNodes.length > 0) {
v.parentNode.insertBefore(v.childNodes[0], v);
}
v.parentNode.removeChild(v);
} else if (v.readyState == 0) {
window.setTimeout(checkVideo, 249);
}
},
checkVideoRendered = function() {
if (v.networkState == 1 && v.readyState == 4) {
v.style.position = op;
v.style.left = ol;
v.style.right = or;
for (var i = 0; i < fe.length; i++) {
fe[i].parentNode.removeChild(fe[i]);
}
} else {
window.setTimeout(checkVideoRendered, 249);
}
}
if (navigator.userAgent.indexOf('iPad') == -1 && navigator.userAgent.indexOf('iPhone') == -1 && navigator.userAgent.indexOf('iPod') == -1) {
window.setTimeout(checkVideo, 249);
}
})('a_34f70ecee1184bd4a29c469ebf00b8b7');
Amy Luo：
您好，
下面链接FAQ中列出了TI CODECs 的常见噪音问题，您可以先看下：
https://e2e.ti.com/support/audio-group/audio/f/audio-forum/901452/faq-audio-codecs-and-adcs-common-noise-issues?tisearch=e2e-sitesearch&keymatch=faq%3Atrue
MIC悬空且有设置MIC通路的话，有底噪应该是正常的，因为MIC输入端会耦合系统产生的电磁干扰；
明天我再细看一下您的问题
,
user6596902：
好的，MIC悬空我们只是测试的，实际上我们尝试过接不同的麦克风，发现都会有这个底噪
,
Amy Luo：
您直接在MIC输入端输入正弦波，查看噪声是否仍然存在？
,
user6596902：
这是录的1Khz的正弦波，麻烦您看一下单击此处播放此音频剪辑
(function(id)
{var v = document.getElementById(id);var op = v.style.position, ol = v.style.left, or = v.style.right, fe = [],checkVideo = function() {if (!v.canPlayType || v.error) {while (v.childNodes.length > 0) {v.parentNode.insertBefore(v.childNodes[0], v);}v.parentNode.removeChild(v);} else if (v.readyState == 0) {window.setTimeout(checkVideo, 249);}},checkVideoRendered = function() {if (v.networkState == 1 && v.readyState == 4) {v.style.position = op;v.style.left = ol;v.style.right = or;for (var i = 0; i < fe.length; i++) {fe[i].parentNode.removeChild(fe[i]);}} else {window.setTimeout(checkVideoRendered, 249);}}if (navigator.userAgent.indexOf('iPad') == -1 && navigator.userAgent.indexOf('iPhone') == -1 && navigator.userAgent.indexOf('iPod') == -1) {window.setTimeout(checkVideo, 249);}
})('a_0cf3a5b5ab154727a52e32e8915f8350');
,
Amy Luo：
您在MIC输入端仅输入正弦波信号，不要有音频信号输入，然后在输出端口查看输出波形看是否存在噪声？以确认是MIC的问题还是TLV320AIC3104的问题；
另外检查下MIC的偏置电压是否存在噪声？我看到您使用的外部MIC偏置电压，不是TLV320AIC3104产生的
,
user6596902：
明白您的意思了，但是我现在没有信号发生器。
MIC偏置电压测了纹波是正常的。
,
Amy Luo：
信号发生器是做电路设计经常用的仪器，需要具备一台；
我再从TLV320AIC3104方面看下原因
,
Amy Luo：
您好，不知道您的问题解决没有？您可以用同样的DAC通路播放其他的数字音频信号吗？看输出是否存在噪声？因为我想确认下噪声的产生是在ADC（录音）还是在DAC（播放）阶段
,
user6596902：
您好，感谢您的帮忙，该问题已经解决了，是由于软件上把噪声放大了导致产生自激
