Nippon Telegraph and Telephone Public Corporation

Tatsuro Masamura

Masahiro Morikura

Takayoshi Maki

An improved oscillator which can adjust phase and frequency of the output signal independently from each other without time delay is disclosed. The oscillator is used for instance as a clock signal generator in a TDMA satellite communication system. The oscillator (FIG. 3) comprises a fixed oscillator (13) for providing a fixed frequency signal, a quadrature hybrid circuit (14) for providing a pair of quadrature phased signals from the output of said fixed oscillator (13), a control signal generator (17) for providing a pair of quadrature phased signals which satisfy b cos (2.pi..DELTA.f.sub.D t+.DELTA..phi..sub.D) and b sin (2.pi..DELTA.f.sub.D t+.DELTA..phi..sub.D), where b is a constant, .DELTA.f.sub.D is a desired frequency change, and .DELTA..phi..sub.D is a desired phase change, a pair of mixers (15,16) for providing products of each output of the quadrature hybrid circuit (14) and each output of the control signal generator (17), and an in-phase power combiner (20) for combining the outputs of the mixers (15,16 ) to provide a controlled output signal which satisfies ab sin [2.pi.(f.sub.O +.DELTA.f.sub.D)t+(.phi..sub.O +.DELTA..phi..sub.D)], where a, f.sub.O and .phi..sub.O are constants.

Growing community of inventors

Kanagawa, Japan

Tatsuro Masamura