Returns the maximum absoluteamplitude that was sampled since the last call to this method.
返回最大绝对振幅，取样自上次调用这个方法。该方法只能在。
2
This information normally exists in the form of signal amplitude (absolute or relative), frequency or spectral content, phase, or timing relationships with respect to other signals.
This information normally exists in the form of signal amplitude (absolute or relative) frequency or spectral content phase or timing relationships with respect to other signals.