PRE-EMPHASIS CIRCUIT

PROBLEM TO BE SOLVED: To provide a pre-emphasis circuit in which external elements are reduces. SOLUTION: An input signal is attenuated by an attenuation circuit 4 and impressed later to a transistor 6a between transistors 6a and 6b consisting of a 1st differential amplifier circuit 5. The output signal of 1st differential amplifier circuit 5 is impressed to transistors 9a and 9b consisting of a 2nd differential amplifier circuit 8 and amplified. The output signal of 2nd differential amplifier circuit 8 is fed back through a capacitor 10 to the attenuation circuit 4 and transmitted through a transistor 11 to become an emitter follower circuit to a following step circuit as an output signal Vout. The output signal Vout is fed back through feedback resistors 12 and 13 to the transistor 6b. Thus, pre-emphasis characteristics can be determined by the respective characteristics of attenuation circuit 4, 1st and 2nd differential amplifier circuits 5 and 8, capacitor 10 and resistors 12 and 13 and without necessity to use the element of large value, all the elements can be made into IC.