ZHCADT8A December   2023  – June 2024 TAA5212 , TAC5111 , TAC5112 , TAC5211 , TAC5212 , TAD5112 , TAD5212

 

  1.   1
  2.   摘要
  3.   商标
  4. 1引言
  5. 2TAX5X1X 音频串行接口
  6. 3TAX5X1X 同步采样速率转换器
    1. 3.1 ADC 采样速率转换
    2. 3.2 DAC 采样速率转换
    3. 3.3 SRC 用例示例
      1. 3.3.1 默认模式(主 Fs - 较高速率)
      2. 3.3.2 带有录制功能的默认模式(主 Fs - 较高速率)
      3. 3.3.3 自定义模式(主 FS - 较低速率)
      4. 3.3.4 带有录制功能的自定义模式(主 FS - 较低速率)
  7. 4总结
  8. 5参考文献
  9. 6修订历史记录

带有录制功能的默认模式(主 Fs - 较高速率)

图 3-6 显示了该用例的方框图。PASI 以 48 KHz 运行,SASI 以 16 KHz 运行。在该用例中,模拟输入(MIC) 以主 Fs 进行采样,并使用 SRC 进行下采样,以降低 SASI 的速率。PASI TX 是采样的 MIC 输入与 SASI RX 或 PASI RX 的混合信号。在 DAC 侧,SASI RX 数据可以在 DAC 输出(扬声器)之前与 PASI RX 数据进行混频。

 具有录制功能的默认模式图图 3-6 具有录制功能的默认模式图

下文显示了 PASI 和 SASI 的 Audio Precision APx555 配置。在该测试用例中,混频器系数保持为默认值(满量程),输入电平会被调整为不超过允许的最大电平(例如 -9dBrG),而不是 0dBrG。

PASI APx555:

发生器:

模拟输出 (MIC):1KHz 正弦波,-9dBrG (0dBrG = 2Vrms)

分析器:

输入 1:PASI Tx 的数字音频,其中 Fs = 48 KHz、32 位深度

输入 2:DAC 输出(扬声器)的模拟输入

SASI APx555:

发生器:

数字输出:750Hz 正弦波,-9dBFS

分析器:

输入 1:SASI Tx 的数字音频,其中 Fs = 16 KHz、TDM、32 位深度

##### PASI higher rate than SASI ADC and DAC SRC Testing with Recording ######
# Target Mode, TDM, 32-bit
# Primary and Secondary ASI, multiple of 48KHz Sampling
# GPIO2=Secondary FSYNC, GPIO1=Secondary BCLK, GPI1=Secondary DIN, GPO1=Secondary DOUT for 4x4
#
w a0 00 00            # Set page 0
w a0 01 01            # Software Reset
w a0 02 09            # Wake up with AVDD > 2v and all VDDIO level
w a0 0a 10            # GPIO1 as input
w a0 0b 10            # GPIO2 as input
w a0 0d 02            # GPI1 as input
w a0 0c 71            # GPO1 as Secondary DOUT
w a0 11 a2            # Enable PASI DIN and Set GPI2A as Secondary FSYNC and GPIO1 as Secondary BCLK
w a0 12 60            # Set GPI1A as Secondary DIN
w a0 18 00            # Enable both Primary and Secondary ASI as independent
w a0 34 40            # PASI BCLK is the input clock source
w a0 19 00            # 1 data input and 1 data output for PASI and SASI
w a0 1a 30            # PASI TDM, 32 bit format
w a0 1e 00            # Tri-state PASI Ch1 to avoid conflict with mix on TDM slot 0
w a0 1f 01            # Tri-state PASI Ch2 to avoid conflict with mix on TDM slot 1
w a0 22 20            # PASI DOUT Ch5 - ASI Loopback data on TDM slot 0
w a0 23 21            # PASI DOUT Ch6 - ASI Loopback data on TDM slot 1
w a0 28 20            # PASI DIN Ch1 on TDM slot 0
w a0 29 21            # PASI DIN Ch2 on TDM slot 1
w a0 00 03            # Set page 3
w a0 1a 30            # SASI TDM, 32 bit format
w a0 1e 20            # SASI DOUT Ch1 on TDM slot 0
w a0 1f 21            # SASI DOUT Ch2 on TDM slot 1
w a0 28 20            # SASI DIN Ch1 on TDM slot 0
w a0 29 21            # SASI DIN Ch2 on TDM slot 1
w a0 00 01            # Set page 1
w a0 17 00            # Default SR-Converter with auto-detect enable
w a0 18 00            # Default auto m:n ratio
w a0 2c d0            # Enable DAC, Side Chain and Loopback Mixer
w a0 00 11            # Set page 0x11
w a0 0c 00 00 40 00   # Route Main DIN Ch1 to LDAC2 Mixer, full scale 
w a0 14 40 00 00 00   # Route Main DIN Ch2 to RDAC2 Mixer, full scale
w a0 4c 00 00 40 00   # Route Aux DIN Ch1 to LDAC2 Mixer, full scale 
w a0 54 40 00 00 00   # Route Aux DIN Ch2 to RDAC2 Mixer, full scale
w a0 5e 40 00         # ADC Loopback Ch1 to SC_LDAC2 Mixer to mix with LDAC2, full scale 
w a0 64 40 00         # ADC Loopback Ch2 to SC_RDAC2 Mixer to mix with RDAC2, full scale
w a0 00 00            # Set page 0
w a0 50 00            # ADC Ch1 diff input, 5KOhm, 2Vrms ac-coupled, audio band
w a0 55 00            # ADC Ch2 diff input, 5KOhm, 2Vrms ac-coupled, audio band
w a0 64 20            # Configure OUT1P/M as differential from DAC1
w a0 65 20            # Configure OUT1P LINEOUT 0dB audio band
w a0 66 20            # Configure OUT1M LINEOUT 0dB 2Vrms Differential 
w a0 6b 20            # Configure OUT2P/M as differential from DAC2
w a0 6c 20            # Configure OUT2P LINEOUT 0dB audio band
w a0 6d 20            # Configure OUT2M LINEOUT 0dB 2Vrms Differential 
w a0 76 cc            # Enable Input and Output Ch1 and Ch2
w a0 78 e0            # Power up ADC, DAC and MICBIAS

测试结果

以下各图显示了 SRC 之后 SASI TX 处的 ADC 输出结果。正如预期那样,频率响应 (FFT) 在 8KHz(16kHz SASI 速率的 Fs/2)处结束。

图 3-7 SRC 之后来自 MIC 输入的 SASI TX 1KHz 音调:

 SASI ADC 输出图 3-7 SASI ADC 输出

在扬声器输出端,捕获的音调是 SRC 之后 750Hz 的 SASI RX 音调。PASI RX 音调将被静音。PASI TX 是 MIC 输入与 750Hz SASI RX 音调的混合信号。

图 3-8 显示了 PASI TX 是 MIC 输入与 SRC 之后 SASI RX 的混合信号。

图 3-9 显示了来自 SRC 之后 SASI RX 的 750Hz 音调,其中 PASI 音调被静音:

 PASI ADC 输出图 3-8 PASI ADC 输出
 扬声器输出图 3-9 扬声器输出