| 摘要 |
PURPOSE:To prevent the interference to the radio unit in the vicinity, by preventing the spread of the carrier frequency spectrum with amplitude modulation, through the provision of the delay circuit taking longer the leading and trailing time of rectangular waves and through the intermission of carrier with the output of delay circuit. CONSTITUTION:When the transistor 21 of the delay circuit IV taking longer the leading and trailing of the rectangular waves of the rectangular wave osicllation circuit V is ON, electromagnetic waves are radiated since miximum carrier current flows to the bar antenna coil 6 of the carrier power amplifying circuit II. When the transistor 21 is OFF, the transistor 9 is OFF, no current flows to the bar antenna coil 6 and no electromagnetic waves are radiated. Since the leading and trailing of the amplitude modulation signal constitute exponential curve having the time constant of the (resistor 23)X(capacitor) 22 of the delay circuit IV, the harmonics included in the amplitude modulation signal is less and the giving of electromagnetic wave interference is less. |
