# A reference request for zero-order hold (ZOH)

From Wikipedia:

A zero-order hold reconstructs the following continuous-time waveform from a sample sequence $x[n]$, assuming one sample per time interval $T$: $$x_{\mathrm{ZOH}}(t)\,= \sum_{n=-\infty}^{\infty} x[n]\cdot \mathrm{rect} \left(\frac{t-T/2 -nT}{T} \right) \$$ where $\mathrm{rect}()$ is the rectangular function.

I'd like to find a good bibliographic reference for it.

Thanks in advance.

• There's a reference in the Wikipedia page; is that good enough?
– MBaz
Jan 28 '16 at 15:03
• Unfortunately, this reference is not of help to me.
– Mark
Jan 28 '16 at 15:05
• Have you tried a quick search on books.google.com? I get almost 600,000 results.
– MBaz
Jan 28 '16 at 15:22
• @MBaz, yes but I'd like to get a hint of a "good" reference :)
– Mark
Jan 28 '16 at 15:24

## 1 Answer

I'd personally start with "Signals and Systems" by Oppenheim and Willsky. I have the second edition, and it has a good description of zero-order hold. This book is a must-have if you're interested in signals and systems. There is also a version that focuses on discrete signals. In addition, this book is probably available at most engineering libraries.