| 摘要 |
A RECEIVING CIRCUIT MAINLY AVAILABLE IN A DIGITAL MODULATION TYPE COMMUNICATION SYSTEM HAVING A PLURALITY OF CHANNELS, WHICH IS CAPABLE OF REDUCING POWER IN A RECEIVING SYSTEM, SIMPLIFYING THE CIRCUIT AND REDUCING THE POWER CONSUMPTION. UPSIDE AND DOWNSIDE FREQUENCIES CORRESPONDING TO A CENTRAL VALUE BETWEEN CHANNELS ARE SEPARATELY SUPPLIED FROM A LOCAL FREQUENCY SIGNAL GENERATING CIRCUIT (4) TO FIRST AND SECOND FREQUENCY CONVERTING CIRCUITS (2, 3) SO THAT TWO OUTPUT SIGNALS ARE DEVELOPED WITH RESPECT TO ONE OF A DESIRED WAVE, UPSIDE CHANNEL AND DOWNSIDE CHANNEL. THE DESIRED WAVE PRESENT IN COMMON IN THE FIRST AND SECOND FREQUENCY CONVERTING CIRCUITS (2, 3) IS EXTRACTED IN A COMMON WAVE EXTRACTING CIRCUIT (5), AND A FREQUENCY OFFSET OF *O EXISTING IN THE OUTPUT OF THE COMMON WAVE EXTRACTING CIRCUIT (5) IS REMOVED A FREQUENCY OFFSET CIRCUIT (6) AND FURTHER AN UNNECESSARY FREQUENCY COMPONENT IS FILTERED BY A FILTER (8). IN ADDITION, THE COMMON WAVE EXTRACTING CIRCUIT (5) HAS TRANSFORMERS AND, USING ITS INDUCTANCES, RAISES THE DIFFERENCE BETWEEN THE COMMON WAVE AND THE NON-COMMON WAVE WITHIN THE CIRCUIT TO MORE THAN TWO TIMES THAT OF A PRIOR ART (FIG.1)
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