| 摘要 |
PURPOSE:To observe an eye pattern of a modulator and demodulator installed at a remote station by storing an output series of a demodulator in the 1st modulator and demodulator, using a subchannel so as to transmit the stored series signal to the 2nd modulator and demodulator and displaying a series signal in the 2nd modulator and democulator. CONSTITUTION:In case of the octal phase modulation in the CCITT recommendations V.27, 1,600 of values a, b are obtained respectively for 1sec. Thus, the information of eye pattern for 1sec is stored with a capacity of 1,600X2= 3,200 words as the capacity of a storage circuit 9. Since 200 pieces of information are obtained in average for one eye pattern at 1sec in case of the octal phase modulation, the accuracy of observation is enough. The information stored in the storage circuit 9 is transmitted to a display device 12 further via transmission/reception circuits 10, 11 of the subchannel and the display device 12 displays the eye pattern of a modulator and demodulator 1. Thus the state of the transmission line and the modulator and demodulator is supervised in the rate of once per about 4min. |
