| 摘要 |
<p>An analogue-to-digital converter (ADC) employs one or more ladders (fig.2: 24, 26) for receiving an input signal to be quantised, and current sources 28, 30 for providing reference currents through the ladders. The ladders are connected to comparators 321-7. The ladders comprise multiple impedances, e.g. resistors, in series. The converter also includes switching arrangements 125, 127, for connecting ladder resistors into or out of circuit. The switching is controlled by a controller 136 in dependence on the value of the quantised output signal. It is thus possible to reduce the voltage headroom required in the reference ladders, thereby allowing accurate quantisation in converters requiring low supply voltages.</p> |
