Frequency converter for varying the frequency of a local signal over a wide band
AssigneeAdvantest Corporation
InventorShoji Niki
Life of this patent
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Abstract
An input signal of a frequency f.sub.0 is supplied to one end of a photodiode. Optical signals of frequencies F.sub.0 and F.sub.0 +.DELTA.F from two light sources are combined by a semitransparent mirror and the resulting interference light is applied to the photodiode. The interference light is converted by the photodiode to an electrical local signal of a frequency .DELTA.F. The electrical local signal and the input signal are frequency mixed in accordance with the nonlinear characteristic of the photodiode and an intermediate-frequency signal of a frequency corresponding to the frequency difference between them is provided at an output terminal.
Claims5
A frequency converter comprising:
- an electrical input terminal for receiving an input electrical signal having a frequency f.sub.0 ;
- photodetector means, connected to said electrical input terminal, for receiving said input electrical signal, said photodetector means having a nonlinear characteristic;
- local light source means for simultaneously applying two optical signals having different frequencies F.sub.0 and F.sub.0 +.DELTA.F to said photodetector means;
- and
- signal extracting means for electrically extracting an electrical intermediate frequency signal from said photodetector means, the electrical intermediate-frequency signal having a frequency which is the difference between the frequency f.sub.0 of said input electrical signal and a frequency difference .DELTA.F between said two optical signals.
Dependencies are inferred from the claim text.