| 摘要 |
PROBLEM TO BE SOLVED: To provide the pre-emphasis circuit where the number of externally mounted components is reduced in the case of circuit integration. SOLUTION: An input signal is amplified by a 1st differential amplifier circuit 4, the amplified signal is fed to a 2nd differential amplifier circuit 9 via a capacitor 8 and amplified. Moreover, an output signal from the 2nd differential amplifier circuit 9 is logarithmically compressed by a 3rd differential amplifier circuit 11 and logarithmically expanded by a 4th differential amplifier circuit 16, and fed back to the 2nd differential amplifier circuit 9. An output signal from the 2nd differential amplifier circuit 9 is added to the input signal at an adder circuit 18 and logarithmically compressed and expanded respectively by the 3rd and 4th differential amplifier circuits 11, 16. Since emitter resistors of transistors(TRs) in differential connection are able to be utilized, a pre-emphasis characteristic is obtained without increasing the capacitance of the capacitor. |
