| 摘要 |
PROBLEM TO BE SOLVED: To provide a digital signal amplifying circuit that does not easily change the duty ratio, even if the level of the logical level 'L' in the input signals is excessive, and to provide an optical receiving circuit to apply the digital signal amplifying circuit. SOLUTION: Input signals are converted into digital signals after resetting of the level detecting circuit, which composes the automatic controlling circuit of the threshold voltage in the latter step, by the reset signal formed by means of detecting the timing that the outputs of the level detecting circuit in the master side, which composes the automatic controlling circuit of threshold voltage with the master-slave types of the first stage, begin to change from the voltage of non-signal state, and detecting the timing that the outputs of the level detecting circuit in the slave side change to the voltage different from the outputs of the level detecting circuit in the master side. |
