HIGHVISION FM RECEIVING DEVICE

Japanese Patent JPH01309596

A

PURPOSE:To prevent the deterioration of the SN ratio of a chromaticity signal (EC) at the time of an FM demodulation by FM-modulating a highvision signal with a luminance signal (EY) and the chromaticity signal (EC) as a composite signal (EM) and transmitting the FM-modulated highvision signal. CONSTITUTION:A difference frequency between the frequency of an FM modulated wave input signal 1 and the frequency of a local oscillator 3 is generated in a frequency converter 2 and added to an FM demodulator 6, and the EY having a small FM demodulation noise is extracted in a low-pass filter 7 and outputted. An antiphase IF is generated from the positive phase IF of the frequency converter 2 with a frequency converter 4 and a fixed oscillator 5. The positive-phase IF of the output of the frequency converter 2 and the antiphase IF of the output of the frequency converter 4 are added to electronic switches 14 and 15 and switched with cosomegasct of the output of a subcarrier oscillator 12 and sinomegasct of the output of a 90 deg. phase shifter 13, the outputs are respectively demodulated in FM demodulators 16 and 17, and an EC1 output 22 and an EC2 output 23 are obtained in low-pass filters 18 and 19. Thus, the title device is simple as a transmitting system for an FM modulated wave, its receiving system is simple, the device never receives the influence of a high-level noise at the time of the FM demodulation, and the SN ratio of the chromaticity signal can be satisfactory.

SAKATA HARUO

JP14082988A

December 13, 1989

June 08, 1988

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CLARION CO LTD

H04N11/00; H04B1/16; H04N7/00; H04N7/015; H04N9/64; H04N11/24; (IPC1-7): H04B1/16; H04N7/00; H04N9/64; H04N11/00

Takesaburo Nagata

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