| 摘要 |
PURPOSE:To insert character broadcast without deteriorating the characteristic of video signals, by forming a carrier chrominance signal with a character encoder from the three primary signals relating to the character broadcast signal formed at the character decoder and inserting this charrier chrominance signal to the video signal section of composite video signal via a mixer. CONSTITUTION:A gate 43 constituting an adaptor 31 is switched with gate pulses and only the information packet of desired channel for the reception of character broadcast is transmitted to a character decoder 45 from a composite video signal outputted from a circuit 42. The decoder 45 decodes the character broadcast signal into three primary color signals R', G', B' for output. The carrier chrominance signal is formed at a character encoder 46 from the three primary signals and a mixer 47 inserts it to the video signal section of required scanning line of composite video signal and the insertion timing is made with the control signal of the decoder 45. Thus, the composite video signal with character broadcast can be formed without deteriorating the characteristics of the video signal. |
