Multiplex transmission system and signal generator therefor

Abstract

Abstract PURPOSE:To reduce a hue change on the screen of a television receiver caused by multiplexing a signal to an orthogonal DC component by modulating orthogonally video carrier by means of multiplex signal so that adjacent data goes to an inverse phase such as FM or PE codes to transmit it. CONSTITUTION:Multiplexed voice signal is added to an input terminal 111 and the voice signal is converted into digital signal in an ADC112. Digital code is digital modulated such as FM and PE in a coding circuit 114, and unnecessary high pass component is removed through a low pass filter 115. With the digital coded voice, the video signal carrier phase-shifted by 90 degrees through a phase shiftier 116 is modulated in a modulator 117. For preventing the influence of a receiver orthogonality due to the characteristic of an IF Nyquist filter in a receiver, addition is executed with the carrier modulated in video signal through an equalizer 122 having the inverted characteristic of the IF Nyquist filter by using an adder 118. As a result, the video carrier is modulated with the video signal and the digital coded voice signal in an orthogonal relation.

Inventors

• 👤 Takatoshi Shirosugi
• 👤 孝敏 城杉
• 👤 Tsutomu Noda
• 👤 勉 野田
• 👤 Takao Arai
• 👤 孝雄 荒井
• 👤 Nobutaka Hotta
• 👤 宣孝 堀田

Bibliographic Details