| 摘要 |
PCT No. PCT/JP90/01284 Sec. 371 Date Jun. 5, 1991 Sec. 102(e) Date Jun. 5, 1991 PCT Filed Oct. 4, 1990.In an FM demodulator which is used in a video tape recorder and in which the linearity of input/output signals is not easily assured to increase a demodulation enable frequency, an FM signal is supplied to the base of a first transistor constituting a first differential amplifier, and a constant voltage is input to the base of a second transistor. A constant voltage is applied to the base of a third transistor constituting a second differential amplifier, and an FM signal having a phase opposite to the FM signal supplied to the first transistor is supplied to the base of a fourth transistor. A capacitor is connected between the emitters of the first and second transistors and the emitters of the third and fourth transistors. A first constant current circuit is arranged between the emitters of the first and second transistors, and a second constant current circuit having a current value twice that of the first constant current circuit is arranged between the emitters of the third and fourth transistors.
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