| 摘要 |
PURPOSE:To prevent a packaging area from being expanded even when the number of components of a circuit is increased, by providing a means which switches the output current of a rectifier to zero or a constant current. CONSTITUTION:A compander circuit is constituted by providing the rectifier and a variable gain cell. In such constitution, assuming V1=0 and V2=Vcc, since transistors(Tr)Q1 and Q6 are turned off, the output current IG of the rectifier goes to zero, and a current to be supplied to the variable gain cell goes to zero, then, the gain of the variable gain cell goes to zero. In other words, the compander circuit is set an OFF state, therefore, the output signal of the compander circuit disappears. Also, assuming V1=Vcc and V2=0, since the TrQ1 is turned on, and Trs Q2, Q7, Q8, and Q9 are turned off, the current IG goes IG=I0, which represents the constant current. And by setting the value of the current I0 at a prescribed value, the compression and expansion characteristic of the compander circuit is eliminated. Namely, the same state as the through state of the compander circuit is generated at this time. |
