| 摘要 |
The present invention provides a phase shifting apparatus and method. The phase shifting apparatus comprises a signal generator and a converting device. An input signal is converted by the offset signals from the signal generator, thereby producing an output signal with the same frequency as that of the input signal. The phase of the output signal is determined by the difference of the offset signals applied to the converting device. In particular, when two offset signals are in quadrature, the output signal becomes in quadrature with the input signal. When the two offset signals have the same phase, the output signal has the same phase as that of the input signal. Preferably, the converting device includes two cascaded offset means, each having a multiplier and a filter coupling to the multiplier. A plurality of converting means may be coupled in parallel to the signal generator. On the basis of the offset signals applied to respective converting means, the phase shifting apparatus provides a plurality of outputs having different phase shifts. The frequency range of the input signal is very width and the phase shifting apparatus may operate in analog and digital forms.
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