| 摘要 |
PURPOSE:To prevent a picture with deteriorated quality from being transmitted by providing a circuit discriminating deterioration in picture quality due to a communication line, discriminating the picture quality by this circuit prior to the end of reception of one original and interrupting the reception on the way of communication if the quality of picture is deteriorated. CONSTITUTION:When a head forced white picture element section 21 or a tail forced white picture element section 23 counts more number of black picture elements than a prescribed reference value, a noise is generated on the communication line and it is discriminated that the picture quality is deteriorated. A pulse generator 12 receives a picture signal from a demodulator 11 and generates a pulse 24 or 25 at each scanning line. The pulse 24 is generated at the front edge of the head forced white picture section 21 and the pulse 25 is generated at the tailing edge. The counter 13 receives an output of the demodulator 11, counts the number of block picture elements and outputs the count value to a comparator circuit 14 in the form of a binary parallel signal. This counter 13 receives the pulse 24 of the front edge of the head forced white picture element section 21 generated at the pulse generator 12 in its reset input and resets the contents of count by the pulse 24. The comparator circuit 14 compares the contents of count of the counter 13 with an output of a setting circuit 15 and outputs ''1'' or ''0''. |
