| 摘要 |
<p>An analog-to-digital converter comprising a delta-sigma modulator (64), a multi-bit A/D converter (53), a second order differentiator (55) and an output summing element (59). The delta-sigma modulator (64) comprises two integrators (42,43), a one bit A/D converter (54), a one bit D/A converter (52) and an input summing element (41) which receives an analog input signal (40) and an output signal (48) of the one bit D/A converter (52). The output of the second integrator (43) is fed to the multi-bit A/D converter (53). The digital output (49) of the converter (53) is applied to a second order differentiator (55) where it is differentiated twice in order to digitally represent the analog output signal (57) of the input summing element (41). The second order differentiated signal (58) is digitally added to the output signal (47) of the delta-sigma modulator (64). The output (50) of the summing element (59) is a digital representation of the analog input signal (40). The analog-to-digital converter has a relatively low loop bit rate and provides a dynamic range of 120 - 140 dB.</p> |
