| 摘要 |
<p>PROBLEM TO BE SOLVED: To accurately measure a high speed signal by holding a first signal to be sampled, modulating a second signal according to a difference between the first and second signals, generating a signal representing the difference, and adding the difference to the held signal value. SOLUTION: A light pulse PF from a laser pulse source 30 is passed through a polarizer 40 so as to be converted into a light signal Pin, a polarization plane is turned clockwise by means of a light modulator 20A to which a signal Vin is given from a signal source 10, and output is carried out to a light modulator 20B receiving a sample hold signal HD from a holding circuit 80. Electric fields of electrodes in the light modulators 20A, 20B are opposed to each other in the opposite directions mutually. A polarization plane of the light signal Pin is turned counterclockwise by means of the light modulator 20B, an output light signal Pout corresponding to a difference between a signal Vin and the previously sampled signal Vin is photoelectrically converted by means of a photodetector 60 via an analyzer 50, and an electric signalΔHD representing the difference is outputted from a detection circuit 70. An addition circuit 90 adds a sample holding signal HD of the holding circuit 80 and the differenceΔHD together so as to sequentially update a sample holding signal HD.</p> |
