| 摘要 |
PURPOSE:To simplify circuit constitution and prevent tone quality in a circuit from deterioration by increasing or decreasing current of variable current source according to fade-in or fade-out starting signals from outside. CONSTITUTION:A D/A converter main body 1 is provided with a variable current source 12, an N bit counter 2 and a current value control circuit 13, and this main body is connected to an integrator 5 with an integration capacitor C through a current cut-off switch S1. The control circuit 13 of the main body 1 inputs fade-in or fade-out signals through a fade-in/fade-out signal input terminal 10, and the current source 12 is controlled depending upon these inputted signals. The digital signal inputted from a digital input terminal 4 controls the current value which charges the capacitor C, and circuit constitution is simplified, thereby preventing tone quality of analog signals from deterioration. |
