| 摘要 |
PURPOSE:To convert a transversal filter into an IC or an LSI by replacing an analog element such as a resistance, etc. with a digital element performing D/A conversion or a memory circuit. CONSTITUTION:An input data train is fed to a shift register 5 consisting of M taps and then shifted by an N-fold clock frequency. Each tap output is connected to a specific input bit of a D/A converter 8 respectively, and the D/A converter output produces the voltage of a level equal to the voltage obtained via a conventional resistance. The accuracy of voltage depends on the bit number K, and the characteristics equivalent to a resistance can be obtained if the K is large. The outputs of the D/A converters are added together and then delivered after the higher harmonic component is deleted. In such a constitution, the logic level fluctuation of the register 5 never emerges to obtain good spectrum characteristics. Thus a circuit can be easily converted into an IC or LSI since a single polarity suffices with the output of the register 5 and no resistance is needed. |
