[参考译文] ADS8681：转换值中出现间歇性错误

您好 Dale、

感谢您的回复。

电路之前没有使用放大器、而50欧姆电阻器用于阻抗匹配、因为该电路旨在用作50欧姆系统的一部分。 我还尝试移除了这个电阻器、但它没有产生任何影响。

1.我尝试向 ADC 施加1V 直流信号、ADC 范围设置为+/- 2.5V。 这些干扰仍然存在、 有关转换数据、请参阅下面的内容。 遗憾的是、我无法使用目前可用的设备捕获数据信号(SCLK、CONVST、SDI、SDO)。

[0xb30d, 0xb308, 0xb30c, 0xb312, 0xb305, 0xb32b, 0xb311, 0xb32a, 0xb307, 0xb321, 0xb30e, 0xb311, 0xb316, 0xb30e, 0xb31f, 0xb327, 0xb301, 0xb325, 0xb331, 0xb31a, 0xb311, 0xb319, 0xb300, 0xb309, 0xb2fa, 0xb311, 0xb322, 0xb304, 0xb309, 0xb311, 0xb316, 0xb30c, 0xb30b, 0xb317, 0xa0d, 0x1b3, 0x11b3, 0x16b3, 0xdb3, 0x9b3, 0x18b3, 0xffb3, 0x25b2, 0x17b3, 0xdb3, 0xb30a, 0xb308, 0xb301, 0xb311, 0xb320, 0xb300, 0xb31b, 0xb329, 0xb319, 0xb325, 0xb31c, 0xb327, 0xb31e, 0xb30f, 0xb311, 0xb311, 0xb311, 0xb319, 0xb319, 0xb309, 0xb305, 0xb329, 0xb30e, 0xb311, 0xb326, 0xb300, 0xb315, 0xb32d, 0xb30f, 0xb311, 0xb30d, 0xb319, 0xb311, 0xb311, 0xb31e, 0xb2f9, 0xb32c, 0xb331, 0xb334, 0xb32f, 0xb32c, 0xb31d, 0xb319, 0xb309, 0xb309, 0xb32f, 0xb332, 0xb31b, 0xb326, 0xb305, 0xb331, 0xb311, 0xb319, 0xb317, 0xb319, 0xb331, 0xb310, 0xb326, 0xb306, 0xb314, 0xb305, 0xb309, 0xb319, 0xb305, 0xb319, 0xb2fb, 0xb311, 0xb325, 0xb30f, 0xb319, 0xb326, 0xb306, 0xb325, 0xb319, 0xb310, 0xb321, 0xb2e8, 0xb2f8, 0xb300, 0xb307, 0xb309, 0xb2f5, 0xb30d, 0xb316, 0xb318, 0xb304, 0xb317, 0xb316, 0xb30d, 0xb317, 0xb323, 0xb2f5, 0xb305, 0xb310, 0xb2f9, 0xb319, 0xb316, 0xb2f9, 0xb318, 0xb2ff, 0xb310, 0xb311, 0xb303, 0xb31c, 0xa0d, 0xf9b3, 0x11b2, 0xf8b3, 0x18b2, 0x9b3, 0x9b3, 0x1fb3, 0x24b3, 0x2cb3, 0x5b3, 0x11b3, 0x18b3, 0x19b3, 0x9b3, 0xf9b3, 0x8b2, 0x6b3, 0xf9b3, 0x2eb2, 0x13b3, 0x11b3, 0x11b3, 0x31b3, 0xf9b3, 0x19b2, 0x17b3, 0x18b3, 0xf9b3, 0x9b2, 0x32b3, 0x9b3, 0x1fb3, 0x10b3, 0x11b3, 0x33b3, 0xfb3, 0x19b3, 0x32b3, 0x16b3, 0x19b3, 0x2fb3, 0x8b3, 0x25b3, 0xdb3, 0x19b3, 0x11b3, 0x2db3, 0x10b3, 0x26b3, 0x7b3]

2.我还在施加1kHz 2Vp-p 正弦波时提供了相同的捕获数据。 我使用示波器检查了 AIN_P 上的信号、它符合预期、没有干扰。

[0x943d, 0x917b, 0x8ea5, 0x8b87, 0x8870, 0x855a, 0x8251, 0x7f47, 0x7c31, 0x7935, 0x75fc, 0x72dd, 0x6fcf, 0x6cfa, 0x6a0f, 0x674a, 0x64a5, 0x6206, 0x5fa5, 0x5d43, 0x5b1f, 0x590e, 0x5701, 0x553e, 0x53ae, 0x523f, 0x50f2, 0x4fe5, 0x4efa, 0x4e53, 0x4dc0, 0x4da6, 0x4d7f, 0x4d74, 0x4dbd, 0x4e2d, 0x4eee, 0x4fba, 0x50c9, 0x5205, 0x5383, 0x5505, 0x56e5, 0x58ca, 0x5acd, 0x5cfd, 0x5f4d, 0x61c1, 0x645b, 0x66fa, 0x69db, 0x6ca0, 0x6f83, 0x7291, 0x75b6, 0x78d4, 0x7bde, 0x7efe, 0x8204, 0x8508, 0x8826, 0x8b4a, 0x8e4b, 0x9132, 0xa0d, 0xe694, 0x7e96, 0x3299, 0x959c, 0x79e, 0x11a1, 0x38a3, 0x30a5, 0xc6a7, 0x8aa8, 0xdaa, 0xac0a, 0xad54, 0xae82, 0xaf3c, 0xb01e, 0xb082, 0xb0da, 0xb0b9, 0xb0c8, 0xb081, 0xafd1, 0xaf4f, 0xae9a, 0xad6d, 0xac4b, 0xaad1, 0xa930, 0xa75e, 0xa54e, 0xa367, 0xa11f, 0x9ee6, 0x9c60, 0x99ef, 0x972a, 0x9467, 0x9189, 0x8eb4, 0x8b9c, 0x887c, 0x8555, 0x8259, 0x7f3e, 0x7c38, 0x7927, 0x75fe, 0x72d9, 0x6fcf, 0x6d01, 0x6a11, 0x6753, 0x64ab, 0x621f, 0x5fa7, 0x5d4d, 0x5b1b, 0x5929, 0x571e, 0x5552, 0x53b2, 0x523c, 0x50f1, 0x4fd5, 0x4ef9, 0x4e4e, 0x4dbb, 0x4daa, 0x4d7a, 0x4d82, 0x4db1, 0x4e47, 0x4ee0, 0x4fcd, 0x50b4, 0x520f, 0x5369, 0x550d, 0x56e3, 0x58de, 0x5adc, 0x5d00, 0x5f55, 0x61c0, 0x6452, 0x67e2, 0x6ab1, 0x6d7d, 0x7069, 0x7373, 0x76a0, 0x79b5, 0x7cc3, 0x7fd6, 0x82e3, 0x85ea, 0x8924, 0x8c42, 0x8f38, 0x920b, 0x94fe, 0x97be, 0x9a54, 0x9cf8, 0x9f4e, 0xa1a9, 0xa3c8, 0xa59a, 0xa79a, 0xa984, 0xab13, 0xac4a, 0xadb6, 0xaec7, 0xaf74, 0xb059, 0xb0b1, 0xb0b2, 0xb0df, 0xb0ce, 0xb065, 0xaff3, 0xaf28, 0xadf9, 0xad15, 0xabc9, 0xaa62, 0xa8a0, 0xa6d3, 0xa4c1, 0xa2b7, 0xa090, 0x9e10, 0x9bab, 0x9912]

3.我没有意识到内部抗混叠滤波器的带宽只有15kHz。 我认为、由于 ADC 能够采样高达1Msps、我假设它会更大。 是否有任何方法可以将 ADC 配置 为绕过滤波器？ 如果不是、您能否建议使用类似的 IC 来捕获高达100kHz 的信号？

Luke