| 摘要 |
PURPOSE:To obtain a broad band frequency modulator using a video signal as its modulation signal by connecting 1st and 2nd transistors(TRs) in a differential form and applying the oscillated voltage excited in the resonance circuit to bases of the 1st and 2nd TRs. CONSTITUTION:The 1st and 2nd TRs 11, 12 are connected in a differential form and an oscillated signal is fed to bases of the 1st and 2nd TRs 11, 12 to allow a frequency modulator to give a balanced output. Since the impedance of resonance coils 120, 123 is regarded to be sufficiently smaller than that of varactor diodes 121, 122, the frequency modulator is driven by a low impedance and the modulation signal is entirely applied to the varactor diodes 121, 122 as its control voltage. Thus, the frequency modulation is attained by using a broad band signal such as a video signal. |
