Before revision: The delayed first-order hold, sometimes called causal first-order hold, is identical to the FOH above except that its output is delayed by one sample period resulting in a delayed piecewise linear output signal Impulse response of causal first-order hold hFOH(t).
After revision: Delayed first-order hold, sometimes called causal first-order hold, is identical to FOH above except that its output is delayed by one sample period resulting in a delayed piecewise linear output signal Impulse response of causal first-order hold hFOH(t).