Zero-order hold
（重定向自ZOH）
![Figure 1. The time-shifted and time-scaled rect function used in the time-domain analysis of the ZOH.](/Images/godic/202502/22/Zeroorderhold.impulseresponse.svg0429.png")
![Figure 2. Piecewise-constant signal xZOH(t).](/Images/godic/202502/22/Zeroorderhold.signal.svg0429.png")
![Figure 3. A modulated Dirac comb xs(t).](/Images/godic/202502/22/Sampled.signal.svg0429.png")
The zero-order hold (ZOH) is a mathematical model of the practical signal reconstruction done by a conventional digital-to-analog converter (DAC). That is, it describes the effect of converting a discrete-time signal to a continuous-time signal by holding each sample value for one sample interval. It has several applications in electrical communication.