| 摘要 |
PURPOSE:To prevent spurious radiation and to transmit a picture with good quality by providing respectively a pin diode to plural output circuits of a voltage controlled oscillator and selecting a pin diode to be conducted among the pin diodes by means of a selecting device. CONSTITUTION:The voltage controlled oscillating section has a terminal 49 receiving a control voltage from an active LPF and after an input signal from the terminal 49 is driven and amplified 50, the signal is fed to the voltage controlled oscillators 52 and 54. The frequency variable range of the oscillator 52 is 254- 400MHz and that of the oscillator 54 is 400-674MHz. Further, the anode of the pin diodes 56, 62 and 70 is connected to a contact 84a of a changeover switch 84 via high frequency blocking coils 78, 80 and 82, and the anode of pin diodes 60, 64 and 74 is connected to a contact 84b of the switch 84 via high frequency blocking coils 86, 88 and 90. Then a signal having a desired frequency band is transmitted by selecting the contact of the switch 84. |
