| 摘要 |
PURPOSE:To attain stable signal transmission while avoiding deterioration in a multiplex signal even in a transmission line system whose quality is deteriorated by applying balanced modulation to a signal subjected to base band modulation with a carrier orthogonal to a video signal and multiplexing the result onto the video signal. CONSTITUTION:A television video signal 100 is subjected to balanced modulation at a balanced modulation circuit 102 by using an output of a video carrier generating circuit 101. Plural carriers modulated by using a multiplex digital signal 103 are used to modulate the input by a QPSK modulator 104. Moreover, the QPSK of the plural carriers being an output of a signal synthesis circuit 112 is subjected to balanced modulation at a balanced modulation circuit 114 by using the carrier from a phase shift circuit 113 orthogonal to the carrier of the video signal. Then the signal applying balanced modulation to the video signal 100, a signal 116 resulting from adding carriers, and a signal balanced- modulated by the circuit 114 are synthesized by a signal synthesis circuit 115 to multiplex the digital signal onto the video signal. |
