The article states: >Extract the hidden state to recover the inaccessible data. For this, the attacker needs a clock of sufficient precision. (Surprisingly low

The article states: >Extract the hidden state to recover the inaccessible data. For this, the attacker needs a clock of sufficient precision. (Surprisingly low-resolution clocks can be sufficient, especially with techniques such as edge thresholding.) Might anyone have some good resources or links they could share on this "edge thresholding" technique?