| 摘要 |
<p>A logarithmic amplification circuit is provided with a first transistor 10 having its collector supplied with a first input current, a second transistor 11 having its collector supplied with a second input current and being differentially connected to the first transistor, a comparing circuit 13 for receiving the first and second input currents to supply a signal corresponding to a difference between the two input currents to a base of the second transistor, and first and second constant current circuits 21 and 25 for supplying respective collectors of the first and the second transistors with equivalent compensating current. An output voltage corresponding to a difference between a logarithmically amplified values of the first input current and a logarithmically amplified value of the second input current can be obtained.</p> |
