| 摘要 |
PURPOSE:To simplify a phase detection circuit and to enhance stability, by constituting each of gates of phase shifter, phase selector and a local frequency source by a digital circuit and gating the local frequency source by a phase controlled pulse. CONSTITUTION:A phase detection circuit is constituted of a high frequency amplifier 2, a mixer 3, local frequency sources 4, 13, an intermediate frequency amplifier 5, phase detectors 6, 7, audible frequency amplifiers 8, 9, filters 10, 11, a data processing apparatus 12, a frequency divider 14, a phase selector 15 and gates 16, 17. The frequency of the local frequency source 13 is divided by the frequency divider 14 and the divided frequency are converted to ones mutually shifted in a 90 deg.-phase by the phase selector 15 and modulated to pulse like ones by the gates 16, 17 to be sent to the phase detectors 6, 7. By this method, the complicated adjustment of an analogue circuit is reduced to simplify the circuit and the stable phase detection circuit can be obtained. |
