code> samples, on demand or never.
      </p>

      <ul>
        <li>
          If <code>N</code> is positive, the input is updated every N samples.
        </li>
        <li>
          If <code>N</code> is zero, the input is not updated.
        </li>
        <li>
          If <code>N</code> is negative, the input is updated and N becomes zero.
        </li>
      </ul>

      <p>
        In the example the output is calculated every <code>HOP-SIZE</code>
        samples. It is interesting to notice that 