DIFFERENTIAL PCM TRANSMISSION SYSTEM

• Main Author: WAKAMATSU KUNIO
• Format: Patent
• Language: English
• Published: 22.03.1986
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION; TRANSMISSION

PURPOSE:To eliminate the delay of a rise part of a picture signal and to attain transmission of signals of high quality, by inserting a PCM signal of a prescribed bit which performs no DPCM coding directly to the rise part of each scan cycle of the picture signal when the picture signal undergoes the differential PCM coding at the transmission side and at the same time giving no DPCM decoding to the prescribed bit of the rise part of each scan cycle of the signal received and demodulated at the reception side and using a PCM signal as it is for reproduction. CONSTITUTION:When the transmission of picture signals is started, a switch circuit 17 is changed to the side of a frame memory 12 according to the output of a counter 18 just for a period equivalent to several bits from a rise time point of each scan line of the picture signal. Thus the PCM signal delivered from the memory 12 and underwent the DPCM coding is supplied as it is to a modulation circuit 14. For a receiver 20, the PCM signal underwent the DPCM decoding is supplied to a frame memory 23 since a switch circuit 29 is switched to the side of a modulation circuit 31 by a counter 30 just for a period of serveral bits from the rise time point of each scan line of the signal sent from a transmitter 10. Then said PCM signal is used for reproduction of picture signals through a D/A converter 24.