| 摘要 |
<p>A circuit is disclosed which can be used in quadrature analysis of modulated waveform, in a modulation system for generating the waveform or in a filter circuit which uses both demodulation and modulation. The demodulation system generates in-phase and quadrature-phase values respectively of the waveform, by repeatedly sampling in respective ones of a plurality of sampling time periods an amplitude of the waveform and generating a series of sequential output values dependent upon the sampled amplitude, with each output value being associated with a respective one of the sampling time periods. The sampling means comprises a switch which is responsive to a periodic timing signal to determine said sampling time periods. Further switches are provided for switching communication of the output values for switched time periods alternately between output terminals, the switches also being responsive to a periodic timing signal to determine said switched time periods. The timing signals are generated such that the sampling switch is actuated such that each sampling time period is shorter than the respective switched time period, commences after the start time of the respective switched time period and ceases prior to the end time of the respective switched time period.</p> |
