| 摘要 |
In a delta modulation coder and decoder system, the disadvantageous effects of slope overload are eliminated by reversing the polarity of the feedback signal in the coder and the polarity of the reconstructed analog signal in the decoder whenever slope overload correction is required. This is accomplished by the addition, to both the coder and decoder, of control circuitry which determines whether slope overload correction is required. To make the determination, first the digital output signal of the coder is tested to determine whether its rate of change is equal to a maximum value. Second, the magnitude of the feedback signal is tested to see if it lies below a threshold value. If both these conditions are satisfied, slope overload correction is then performed.
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