| 摘要 |
<p>Circuit for the A/D conversion of a video RF or IF signal by means of a two-step A/D conversion using a first A/D converter with restricted dynamic resolution and a second A/D converter with high resolution the outputs of said converters being added for generating the final digitised signal. Output of first A/D converter is connected via an D/A converter to a subtracting stage lying within the analogue signal path to said second A/D converter. The circuit is simplified by inserting an analogue delay line (4) between the input of the first A/D converter and the substracting stage. As a consequence, one sample and hold circuit used in the prior art is no more needed. The circuit allows the application of low cost A/D converters. Second (fig 2) and third (fig 3) embodiments of the A/D conversion circuit comprise respectively an analogue and digital error correction circuit.</p> |
