Adaptive delta codec which varies a delta signal in accordance with a characteristic of an input analog signal
First Claim
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1. An adaptive delta codec comprising:
- delta coding means which compares the level of an analog input signal and an estimated signal, and generates a coded signal in response to the result of the comparison;
first and second control terminals which receive control signals indicative of the increase or decrease in a delta signal and the estimated signal;
first and second storing means for respectively storing the delta signal and the estimated signal;
adder/subtractor means connected to said first and second storing means in time-division manner, and which decreases an absolute value of the estimated signal in the second storing means during a first time period, changes the delta signal in said first storing means in accordance with the level at said first control terminal during a second time period, and makes an addition or subtraction of the delta signal and the estimated signal in accordance with the level at said second control terminal during a third period, the result of the addition or subtraction in the third period being stored in the second storing means as a new estimated signal.
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Abstract
A delta value generating circuit in an adaptive delta codec, comprising a delta value register, a control terminal for indicating increase or decrease of the delta value and adder/subtractor for increasing or decreasing the delta value in the register in accordance with a level at the control terminal. The adder/subtractor has first input terminals connected to the output terminals of the register and second input terminals connected to a predetermined number of upper bits of the output terminals of the register and the control terminal in accordance with a level at the control terminal.
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2 Claims
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1. An adaptive delta codec comprising:
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delta coding means which compares the level of an analog input signal and an estimated signal, and generates a coded signal in response to the result of the comparison; first and second control terminals which receive control signals indicative of the increase or decrease in a delta signal and the estimated signal; first and second storing means for respectively storing the delta signal and the estimated signal; adder/subtractor means connected to said first and second storing means in time-division manner, and which decreases an absolute value of the estimated signal in the second storing means during a first time period, changes the delta signal in said first storing means in accordance with the level at said first control terminal during a second time period, and makes an addition or subtraction of the delta signal and the estimated signal in accordance with the level at said second control terminal during a third period, the result of the addition or subtraction in the third period being stored in the second storing means as a new estimated signal. - View Dependent Claims (2)
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Specification