| 摘要 |
A digital-to-analog converter is described for converting (b+a)-bit code words into an analog signal by means of a b-bit auxiliary digital-to-analog converter. In order to reduce the quantizing noise introduced by the indispensible quantizing of the (b+a)-bit code words for obtaining the b-bit code words these (a+b)-bit code words are applied to an integrating network which has its output connected to an amplitude-limiting device which brings the integrated signal in the signal range of the auxiliary-D/A converter. The output signal of the amplitude-limiting device is now quantized and this quantizing signal is applied to the auxiliary D/A converter which produces analog output signal samples which are applied to, possibly, an analog output filter through a cascade arrangement of an amplitude-restorer and a difference network. The (b+a)-bit code words are assumed to occur with a frequency which is higher than the Nyquist sampling frequency associated with the analog signal represented by these (b+a)-bit code words. |
