| 摘要 |
PURPOSE:To transmit a signal coincident with the screen accuracy of a receiving terminal and to improve the transmission efficiency by producing a still picture signal which is transmitted in response to a screen accuracy designating signal of the receiving terminal and transmitting a signal that controls the writing of the receiving terminal to a memory together with said picture signal. CONSTITUTION:A transmission controller 22 at the center side controls the screen accuracy of a transmission signal produced by a transmission signal generator 21 in accordance with the screen accuracy designating signal of a receiving terminal. For instance, the information is extracted every second picture element in both vertical and horizontal directions to produce a transmission signal. At the same time, the generator 21 produces a signal that controls the writing of the receiving terminal to a memory and transmitted together with the transmission signal. At the reception side the same information is written every two picture elements in both vertical and horizontal directions for the reception signal. Thus it is possible even for a receiving terminal having high picture accuray to receive the signal without increasing the transmission time. The signal which controls a memory of the receiving terminal writes the same information to a memory with every four picture elements of the receiving terminal on the basis of the screen accuracy designating signal sent from the receiving terminal. |
