MULTIIFREQUENCY SIGNAL TRANSMISSION SYSTEM

摘要

PURPOSE:To secure transmission of the multi-frequency signals to the continous time slots with a reduced amount of the hardware by producing and memorizing all multi-frequency signals via the time slots and in a nonsynchronising way and then selecting one signal designated from outside among those multi-frequency signals for transmission. CONSTITUTION:The type of the multi-frequency signal to be transmitted to the time slot is written into order memory 16 via the external device and based on the address of memory 16 corresponding to the time slot number. Also the single-frequency signals are generated through control circuit 14 for all conceivable combinations of the single-frequencies previously in order to select two units of the single- frequency signals via selectors 9a and 9b. These selected signals are then mixed up at adder 10 to produce the multi-frequency signal. This multi-frequency signal is multiplied by multiplier by the level signal sent from register 13 to be written into buffer memory 18. After this, memory 16 is read out via circuit 14 and with every time slot through selector 15, and the multi-frequency signal to be sent to the time slot is read out from memory 18 based on the contents of memory 16.