This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

[参考译文] ADS1292:DC 导联脱落检测,带有"输入电流源"设置,但噪声为35 Hz

Guru**** 2535380 points
Other Parts Discussed in Thread: ADS1292

请注意,本文内容源自机器翻译,可能存在语法或其它翻译错误,仅供参考。如需获取准确内容,请参阅链接中的英语原文或自行翻译。

https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/1079276/ads1292-dc-lead-off-detection-with-input-current-source-setup-but-with-35-hz-noise

部件号:ADS1292
“线程: 测试”中讨论的其它部件

你好。

我们将 ADS1292用于带有 DC 导联脱落的 ECG 和配置“输入电流源”。
问题是,我们两个信道上的噪音都大约为35 Hz。 输入中使用干燥而不是湿电极。

前端电源由 LDO (LP8900TLE-333/NOPB)提供。 LDO 的输入由880 mAh 的锂聚合物电池供电,额定电压为3.8 V

我们使用的数字滤波器的范围为0.5 Hz 至40 Hz。 我们还在测试的基础上取消了这些测试,以查看35 Hz 是否是数字滤波的副作用。 不幸的是,他们没有。

35 Hz 或以上的频率是否可以从前端产生? 噪声放大器为30 µV,过渡电阻良好,1 mV,过渡电阻差。 使用心电图模拟器时,不会出现干扰。

谢谢你。

此致
勒内·陶舍

我们的示意图:

噪声示例:

我们的固件配置:

        //--- CONFIG1: Configuration Register 1 
        //--- This register configures each ADC channel sample rate
            (0x00 << 7) +       /*!<    Bit 7 SINGLE_SHOT: Single-shot conversion
                                        0 = Continuous conversion mode (default)
                                        1 = Single-shot mode */
            (0x00 << 3) +       /*!<    Bits[6:3] Must be set to '0' */
          
            (0x03 << 0),        /*!<    Bits[2:0] DR[2:0]: Channel oversampling ratio
                                  Attention! fCLK = 512 kHz and CLK_DIV = 0 or fCLK = 2.048 MHz and CLK_DIV = 1.
                                        BIT    OVERSAMPLING RATIO      DATA RATE(1)
                                        000    fMOD / 1024             125 SPS
                                        001    fMOD / 512              250 SPS
                                        010    fMOD / 256              500 SPS (default)
                                        011    fMOD / 128              1 kSPS
                                        100    fMOD / 64               2 kSPS
                                        101    fMOD / 32               4 kSPS
                                        110    fMOD / 16               8 kSPS
                                        111    Do not use Do not use */
        //--- CONFIG2: Configuration Register 2 
        //--- This register configures the test signal, clock, reference, and LOFF buffer
            (0x01 << 7) +       /*!<    Bit 7 Must be set to '1' */
            (0x00 << 6) +       /*!<    Bit 6 PDB_LOFF_COMP: Lead-off comparator power-down
                                        This bit powers down the lead-off comparators.
                                        0 = Lead-off comparators disabled (default)
                                        1 = Lead-off comparators enabled */
            (0x01 << 5) +               /*!<    Bit 5 PDB_REFBUF: Reference buffer power-down
                                        This bit powers down the internal reference buffer so that the external reference can be used.
                                        0 = Reference buffer is powered down (default)
                                        1 = Reference buffer is enabled */
            (0x00 << 4) +       /*!<    Bit 4 VREF_4V: Enables 4-V reference
                                        This bit chooses between 2.42-V and 4.033-V reference.
                                        0 = 2.42-V reference (default)
                                        1 = 4.033-V reference */
            (0x00 << 3) +
            (0x00 << 3) +       /*!<    Bit 3 CLK_EN: CLK connection
                                        This bit determines if the internal oscillator signal is connected to the CLK pin when an internal oscillator is used.
                                        0 = Oscillator clock output disabled (default)
                                        1 = Oscillator clock output enabled */
            (0x00 << 2) +       /*!<    Bit 2 Must be set to '0' */
            (0x00 << 1) +       /*!<    Bit 1 INT_TEST: Test signal selection
                                        This bit determines whether the test signal is turned on or off.
                                        0 = Off (default)
                                        1 = On; amplitude = �(VREFP � VREFN) / 2400 */
            (0x00 << 0),        /*!<    Bit 0 TEST_FREQ: Test signal frequency
                                        This bit determines the test signal frequency.
                                        0 = At dc (default)
                                        1 = Square wave at 1 Hz */
        //--- LOFF: Lead-Off Control Register 
        //--- This register configures the lead-off detection operation
            (0x00 << 5) +       /*!<    Bits[7:5] COMP_TH[2:0]: Lead-off comparator threshold
                                        Comparator positive side        Comparator negative side
                                        000 = 95% (default)             000 = 5% (default)
                                        001 = 92.5%                     001 = 7.5%
                                        010 = 90%                       010 = 10%
                                        011 = 87.5%                     011 = 12.5%
                                        100 = 85%                       100 = 15%
                                        101 = 80%                       101 = 20%
                                        110 = 75%                       110 = 25%
                                        111 = 70%                       111 = 30% */
            (0x00 << 4) +       /*!<    Bit 4 Must be set to '1' */
            (0x00 << 2) +       /*!<    Bits[3:2] ILEAD_OFF[1:0]: Lead-off current magnitude
                                        These bits determine the magnitude of current for the current lead-off mode.
                                        00 = 6 nA (default)
                                        01 = 22 nA
                                        10 = 6 uA
                                        11 = 22 uA */
            (0x00 << 1) +       /*!<    Bit 1 Must be set to '0' */
            (0x00 << 0),        /*!<    FLEAD_OFF: Lead-off frequency
                                        This bit selects ac or dc lead-off.
                                        0 = At dc lead-off detect (default)
                                        1 = At ac lead-off detect at fDR / 4 (500 Hz for an 2-kHz output rate) */
        //--- CH1SET: Channel 1 Settings 
        //--- This register configures the power mode, PGA gain, and multiplexer settings channels.
            (0x00 << 7) +       /*!<    Bit 7 PD1: Channel 1 power-down
                                        0 = Normal operation (default)
                                        1 = Channel 1 power-down(1)
                                        (1) When powering down channel 1, make sure the input multiplexer is set to input short configuration. Bits[3:0] = 001. */
            (0x01 << 4) +       /*!<    Bits[6:4] GAIN1[2:0]: Channel 1 PGA gain setting
                                        000 = 6 (default)
                                        001 = 1
                                        010 = 2
                                        011 = 3
                                        100 = 4
                                        101 = 8
                                        110 = 12 */
            (0x00 << 0),        /*!<    Bits[3:0] MUX1[3:0]: Channel 1 input selection
                                        0000 = Normal electrode input (default)
                                        0001 = Input shorted (for offset measurements)
                                        0010 = RLD_MEASURE
                                        0011 = MVDD(2) for supply measurement
                                        0100 = Temperature sensor
                                        0101 = Test signal
                                        0110 = RLD_DRP (positive input is connected to RLDIN)
                                        0111 = RLD_DRM (negative input is connected to RLDIN)
                                        1000 = RLD_DRPM (both positive and negative inputs are connected to RLDIN)
                                        1001 = Route IN3P and IN3N to channel 1 inputs
                                        1010 = Reserved
                                        (2) For channel 1, (MVDDP � MVDDN) is [0.5(AVDD + AVSS)]; for channel 2, (MVDDP � MVDDN) is DVDD / 4. Note that to avoid
                                            saturating the PGA while measuring power supplies, the gain must be set to '1'. */
        //--- CH2SET: Channel 2 Settings 
        //--- This register configures the power mode, PGA gain, and multiplexer settings channels
            (0x00 << 7) +       /*!<    Bit 7 PD2: Channel 2 power-down
                                        0 = Normal operation (default)
                                        1 = Channel 2 power-down(1)
                                        (1) When powering down channel 2, make sure the input multiplexer is set to input short configuration. Bits[3:0] = 001. */
            (0x01 << 4) +       /*!<    Bits[6:4] GAIN2[2:0]: Channel 2 PGA gain setting
                                        000 = 6 (default)
                                        001 = 1
                                        010 = 2
                                        011 = 3
                                        100 = 4
                                        101 = 8
                                        110 = 12 */
            (0x00 << 0),        /*!<    Bits[3:0] MUX2[3:0]: Channel 2 input selection
                                        0000 = Normal electrode input (default)
                                        0001 = Input shorted (for offset measurements)
                                        0010 = RLD_MEASURE
                                        0011 = MVDD(2) for supply measurement
                                        0100 = Temperature sensor
                                        0101 = Test signal
                                        0110 = RLD_DRP (positive input is connected to RLDIN)
                                        0111 = RLD_DRM (negative input is connected to RLDIN)
                                        1000 = RLD_DRPM (both positive and negative inputs are connected to RLDIN)
                                        1001 = Route IN3P and IN3N to channel 2 inputs
                                        1010 = Reserved
                                        (2) For channel 1, (MVDDP � MVDDN) is [0.5(AVDD + AVSS)]; for channel 2, (MVDDP � MVDDN) is DVDD / 4. Note that to avoid
                                            saturating the PGA while measuring power supplies, the gain must be set to '1'. */
        //--- RLD_SENS: Right Leg Drive Sense Selection 
        //--- This register controls the selection of the positive and negative signals from each channel for right leg drive derivation
            (0x00 << 6) +       /*!<    Bits[7:6] CHOP[1:0]: Chop frequency
                                        These bits determine PGA chop frequency
                                        00 = fMOD / 16
                                        01 = Reserved
                                        10 = fMOD / 2
                                        11 = fMOD / 4 */
            (0x00 << 5) +       /*!<    Bit 5 PDB_RLD: RLD buffer power
                                        This bit determines the RLD buffer power state.
                                        0 = RLD buffer is powered down (default)
                                        1 = RLD buffer is enabled */
            (0x00 << 4) +       /*!<    Bit 4 RLD_LOFF_SENSE: RLD lead-off sense function
                                        This bit enables the RLD lead-off sense function.
                                        0 = RLD lead-off sense is disabled (default)
                                        1 = RLD lead-off sense is enabled */
            (0x00 << 3) +       /*!<    Bit 3 RLD2N: Channel 2 RLD negative inputs
                                        This bit controls the selection of negative inputs from channel 2 for right leg drive derivation.
                                        0 = Not connected (default)
                                        1 = RLD connected to IN2N */
            (0x00 << 2) +       /*!<    RLD2P: Channel 2 RLD positive inputs
                                        This bit controls the selection of positive inputs from channel 2 for right leg drive derivation.
                                        0 = Not connected (default)
                                        1 = RLD connected to IN2P */
            (0x00 << 1) +       /*!<    Bit 1 RLD1N: Channel 1 RLD negative inputs
                                        This bit controls the selection of negative inputs from channel 1 for right leg drive derivation.
                                        0 = Not connected (default)
                                        1 = RLD connected to IN1N */
            (0x00 << 0),        /*!<    Bit 0 RLD1P: Channel 1 RLD positive inputs
                                        This bit controls the selection of positive inputs from channel 1 for right leg drive derivation.
                                        0 = Not connected (default)
                                        1 = RLD connected to IN1P */
        //--- LOFF_SENS: Lead-Off Sense Selection, 
        //--- This register selects the positive and negative side from each channel for lead-off detection,
        //--- Note that the LOFF_STAT register bits should be ignored if the corresponding LOFF_SENS bits are set to '1'.
            (0x00 << 6) +       /*!<    Bits[7:6] Must be set to '0' */
            (0x00 << 5) +       /*!<    Bit 5 FLIP2: Current direction selection
                                        This bit controls the direction of the current used for lead-off derivation for channel 2.
                                        0 = Disabled (default)
                                        1 = Enabled */ 
            (0x01 << 4) +       /*!<    Bit 4 FLIP1: Current direction selection
                                        This bit controls the direction of the current used for lead-off derivation for channel 1.
                                        0 = Disabled (default)
                                        1 = Enabled */
            (0x01 << 3) +       /*!<    Bit 3 LOFF2N: Channel 2 lead-off detection negative inputs
                                        This bit controls the selection of negative input from channel 2 for lead-off detection.
                                        0 = Disabled (default)
                                        1 = Enabled */
            (0x01 << 2) +       /*!<    Bit 2 LOFF2P: Channel 2 lead-off detection positive inputs
                                        This bit controls the selection of positive input from channel 2 for lead-off detection.
                                        0 = Disabled (default)
                                        1 = Enabled */
            (0x01 << 1) +       /*!<    Bit 1 LOFF1N: Channel 1 lead-off detection negative inputs
                                        This bit controls the selection of negative input from channel 1 for lead-off detection.
                                        0 = Disabled (default)
                                        1 = Enabled */
            (0x01 << 0),        /*!<    Bit 0 LOFF1P: Channel 1 lead-off detection positive inputs
                                        This bit controls the selection of positive input from channel 1 for lead-off detection.
                                        0 = Disabled (default)
                                        1 = Enabled */
        //--- LOFF_STAT: Lead-Off Status
        //--- This register stores the status of whether the positive or negative electrode on each channel is on or off.
        //--- Ignore the LOFF_STAT values if the corresponding LOFF_SENS bits are not set to '1'.
            (0x00 << 7) +       /*!<    Bit 7 Must be set to '0' */
			(0x00 << 6) +       /*!<    Bit 6 CLK_DIV : Clock divider selection
                                        This bit sets the modultar divider ratio between fCLK and fMOD. Two external clock values are supported: 512 kHz and 2.048 MHz.
                                        0 = fMOD = fCLK / 4 (default, use when fCLK = 512 kHz)
                                        1 = fMOD = fCLK / 16 (use when fCLK = 2.048 MHz) */
            (0x00 << 5) +       /*!<    Bit 5 Must be set to '0' */
            (0x01 << 4) +       /*!<    Bit 4 RLD_STAT: RLD lead-off status
                                        This bit determines the status of RLD.
                                        0 = RLD is connected (default)
                                        1 = RLD is not connected */
            (0x00 << 3) +       /*!<    Bit 3 IN2N_OFF: Channel 2 negative electrode status
                                        This bit determines if the channel 2 negative electrode is connected or not.
                                        0 = Connected (default)
                                        1 = Not connected */
            (0x00 << 2) +       /*!<    Bit 2 IN2P_OFF: Channel 2 positive electrode status
                                        This bit determines if the channel 2 positive electrode is connected or not.
                                        0 = Connected (default)
                                        1 = Not connected */
            (0x00 << 1) +       /*!<    Bit 1 IN1N_OFF: Channel 1 negative electrode status
                                        This bit determines if the channel 1 negative electrode is connected or not.
                                        0 = Connected (default)
                                        1 = Not connected */
            (0x00 << 0),        /*!<    Bit 0 IN1P_OFF: Channel 1 positive electrode status
                                        This bit determines if the channel 1 positive electrode is connected or not.
                                        0 = Connected (default)
                                        1 = Not connected */
        //--- RESP1: Respiration Control Register 1
        //--- This register controls the respiration functionality. This register applies to the ADS1292R version only. For the
        //--- ADS1291 and ADS1292 devices, 02h must be written to the RESP1 register.
            (0x00 << 7) +       /*!<    Bit 7 RESP_DEMOD_EN1: Enables respiration demodulation circuitry
                                        This bit enables and disables the demodulation circuitry on channel 1.
                                        0 = RESP demodulation circuitry turned off (default)
                                        1 = RESP demodulation circuitry turned on */
            (0x00 << 6) +       /*!<    Bit 6 RESP_MOD_EN: Enables respiration modulation circuitry
                                        This bit enables and disables the modulation circuitry on channel 1.
                                        0 = RESP modulation circuitry turned off (default)
                                        1 = RESP modulation circuitry turned on */
            (0x00 << 2) +       /*!<    Bits[5:2] RESP_PH[3:0]: Respiration phase(1)
                                        These bits control the phase of the respiration demodulation control signal.
                                        RESP_PH[3:0]    RESP_CLK = 32kHz    RESP_CLK = 64 kHz
                                        0000            0� (default)        0� (default)
                                        0001            11.25�              22.5�
                                        0010            22.5�               45�
                                        0011            33.75�              67.5�
                                        0100            45�                 90�
                                        0101            56.25�              112.5�
                                        0110            67.5�               135�
                                        0111            78.75�              157.5�
                                        1000            90�                 Not available
                                        1001            101.25�             Not available
                                        1010            112.5�              Not available
                                        1011            123.75�             Not available
                                        1100            135�                Not available
                                        1101            146.25�             Not available
                                        1110            157.5�              Not available
                                        1111            168.75�             Not available 
                                        (1) The RESP_PH3 bit is ignored when RESP_CLK = 64 kHz. */
            (0x01 << 1) +       /*!<    Bit 1 Must be set to '1' */
            (0x00 << 0),        /*!<    Bit 0 RESP_CTRL: Respiration control
                                        This bit sets the mode of the respiration circuitry.
                                        0 = Internal respiration with internal clock
                                        1 = Internal respiration with external clock */
        //--- RESP2: Respiration Control Register 2
        //--- This register controls the respiration and calibration functionality.
            (0x00 << 7) +       /*!<    Bit 7 CALIB_ON: Calibration on
                                        This bit is used to enable offset calibration.
                                        0 = Off (default)
                                        1 = On */
            (0x00 << 3) +       /*!<    Bits[6:3] Must be '0' */
            (0x00 << 2) +       /*!<    Bit 2 RESP_FREQ: Respiration control frequency (ADS1292R only)
                                        This bit controls the respiration control frequency when RESP_CTRL = 0. This bit must be written with '1' for the ADS1291
                                        and ADS1292.
                                        0 = 32 kHz (default)
                                        1 = 64 kHz */
            (0x01 << 1) +       /*!<    Bit 1 RLDREF_INT: RLDREF signal
                                        This bit determines the RLDREF signal source.
                                        0 = RLDREF signal fed externally
                                        1 = RLDREF signal (AVDD � AVSS) / 2 generated internally (default) */
            (0x01 << 0),        /*!<    Bit 0 Must be set to '1' */
        //--- GPIO: General-Purpose I/O Register
        //--- This register controls the GPIO pins.
            (0x00 << 4) +       /*!<    Bits[7:4] Must be '0' */
            (0x03 << 2) +       /*!<    Bits[3:2] GPIOC[2:1]: GPIO 1 and 2 control
                                        These bits determine if the corresponding GPIOD pin is an input or output.
                                        0 = Output
                                        1 = Input (default)*/
            (0x00 << 0),        /*!<    Bits[1:0] GPIOD[2:1]: GPIO 1 and 2 data
                                        These bits are used to read and write data to the GPIO ports.
                                        When reading the register, the data returned correspond to the state of the GPIO external pins, whether they are
                                        programmed as inputs or as outputs. As outputs, a write to the GPIOD sets the output value. As inputs, a write to the
                                        GPIOD has no effect. GPIO is not available in certain respiration modes. */

  • 请注意,本文内容源自机器翻译,可能存在语法或其它翻译错误,仅供参考。如需获取准确内容,请参阅链接中的英语原文或自行翻译。

    你好,雷恩,

    欢迎来到 E2E 论坛!!!

    根据设计输入,AFE 前端没有任何电路以35 Hz 的频率工作。 因此,干扰可能是通过高阻抗输入而不是内部 AFE 前端电路产生的噪音耦合。 通过将输入通道内部短路到共模电压(MUX2[3:0]= 0001),检查您是否看到相同的干扰可能会有所帮助。

    谢谢

    -TC

  • 请注意,本文内容源自机器翻译,可能存在语法或其它翻译错误,仅供参考。如需获取准确内容,请参阅链接中的英语原文或自行翻译。

    您好,

    感谢大家对论坛的欢迎。

    我的两个通道都设置为输入短路,零线几乎没有任何信号。

    勒内

  • 请注意,本文内容源自机器翻译,可能存在语法或其它翻译错误,仅供参考。如需获取准确内容,请参阅链接中的英语原文或自行翻译。

    你好,雷恩,

    感谢输入-短信道测试数据。 噪音耦合器很可能是设备外部的。

    谢谢

    -TC

  • 请注意,本文内容源自机器翻译,可能存在语法或其它翻译错误,仅供参考。如需获取准确内容,请参阅链接中的英语原文或自行翻译。

    您好,

    我现在还怀疑,在我们的电路板上,我没有发现在频率范围内有什么作用。
    因为我可能会进一步研究。 然后思考一下,如果您以某种方式通过改进的输入电路获得信号会怎样。

    谢谢你。

    勒内

  • 请注意,本文内容源自机器翻译,可能存在语法或其它翻译错误,仅供参考。如需获取准确内容,请参阅链接中的英语原文或自行翻译。

    你好,雷恩,

    我将结束这条线程。 如果您以后有其他问题,请重新打开此主题。  

    谢谢

    -TC