| 摘要 |
PURPOSE:To reduce the click noise giving an unpleasant feeling and to make smooth level adjustment smoothly, by making a suitable interpolation to a digital signal given as a level control signal. CONSTITUTION:An interplation operating device 6 and a shift register 6 are added to a normal amplitude adjuster. A level adjusting signal D outputted from a memory 4 is introduced to a subtractor 8 and a delay signal St-1 is subtracted. After the subtraction output of this subtractor 8 is multiplied by 1/2<n> through a coefficient device 9, it is applied to an adder 10 [where; (n) is a positive integer like 1, 2...]. This device 9 makes coefficient processing with the operation rounded off from the LSB side of a signal value. The adder 10 makes addition of the delay signal St-1 to the output of the device 9 to obtain an interpolation level inquiry signal St, i.e. a new gain St. This value St is inputted to a digital multiplier 5 and stored in a register 7, and it is supplied to an operation device 8 and the adder 10 at the operation at the next time. |
