| 摘要 |
PURPOSE:To ensure an accurate reception for both the double frequency combination signal and the single frequency signal via one unit of the receiver by deciding normal and accepting the signals in case both the 1st and 2nd digits feature the same signal type and on the other hand deciding erroneous and deleting the signals in case the signal type differs between the two digits. CONSTITUTION:When the signal sent from the pushphone is received as the 1st digit of the signal, relay MF operates to keep the operation. In case the single frequency signal is received when the pushphone signal is received at the 1st digit with the operation of relay MF kept, i.e., while the second and subsequent digits of the pushphone signal are being received, alarm relay AL is actuated to alarm the malfunction. |
