ads1293的Digital AC Lead-Off Detect功能怎样使用，看了datasheet，不明白EN_LOD寄存器怎样设置。里面举了个例子，开始说明了两个通道，CH1,CH2，但是后面配置时，需要配置CH3。不太明白，请高人指点？下面是例子原文。
Consider an example where the first AFE is configured through
the flexible routing switch to measure the voltage between IN1 and IN2, and the second AFE is configured
through the flexible routing switch to measure the voltage between IN2 and IN3.
In this configuration, if digital AC LOD test currents are applied to the inputs of both AFEs, the test current that is
applied to the negative input of the first AFE and the test current that is applied to the positive input of the
second AFE are both flowing through IN2. Depending on the sign of the test current in the second AFE, these
currents can add up or cancel each other. If the currents add up, the system will correctly measure the
differential input impedance on both AFE channels. If the currents on IN2 cancel, the test current will only flow
through IN1 and IN3, and the impedance of the electrode connected to IN2 cannot be measured. To apply the
digital AC LOD to CH3 and CH2, set EN_LOD[2] = 1 and EN_LOD[1] = 1. Then, by programming EN_LOD[5] = 0
and EN_LOD[4] = 1, CH3 and CH2 will receive excitation currents in-phase and anti-phase, respectively.
