| 摘要 |
<p>NOISE REDUCTION METHOD /A APPARATUS FOR COMPANDED DELTA MODULATORS A noise reduction circuit and method are described for implementation in a delta modulation system for signal transmission. Under certain conditions when the delta modulator has selected the minimum step size for encoding and transmission, the present technique and apparatus are effective to change the minimum step size in a way which prevents low level noise generation from occurring in the delta modulation system. The technique and circuit can be utilized with most commonly available delta modulators which have means for changing the step size (i.e., the delta) but is used to the best effect on more stable implementations of delta modulators where an integrator is replaced by a digital accumulator and a digitalto-analog converter.</p> |
