| 摘要 |
PURPOSE:To control the automatic changeover of frequencies to evade automatically interference, by automatically detecting the occurrence of interference from the received output of a radio receiver. CONSTITUTION:Input signals from an input terminal (in) are inputted in pulsing circuits 1 and 2 and outputs of the circuit 2 are supplied to clock terminals CK of FFs 4 and 5 through a delay circuit 3, then, outputs of the circuits 1 and 2 are supplied to data terminals of the FFs 4 and 5. Outputs of the FFs 4 and 5 are supplied to counters 8 and 9 through filter circuits 6 and 7 and outputs of the counters 8 and 9 are inputted in an NAND circuit 10. Moreover, the input signals are inputted in a busy detecting circuit 11 and the detected output is used for cleaning the FFs 4 and 5 and, at the same time, supplied to one side of an AND circuit 13 after invertion at an inverter circuit 12. In addition, the output of an oscillator 14 are supplied to the other side of the circuit 13 and the output of the circuit 13 is inputted in a counter 15. The output of the counter 15 is inputted in an FF16 and output of the FF16 is used for clearing the counters 8, 9, and 15. Interference of received outputs is evaded by processing the output of each counter 8, 9, and 15 by means of the FFs 16 and 17. |
