Frequency compression and expansion using an electrooptical processor
US4236043A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 13, 1979 |
| Grant date | Nov 25, 1980 |
| Priority date | — |
| Expiry date | Apr 13, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06E3/005
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of compressing or expanding the frequency of signals while keeping the signals' original gross temporal relationship relies upon an electrooptical processor. An apertured mask is interposed between an area-array charge coupled device (CCD) and a light emitting diode (LED). Optical signals are emitted from the LED at a clock rate which is the same as the vertical shift rate of charge packets in the CCD. Sampling the CCD's horizontal shift register output at varying rates allows a changing of the frequencies of the optical signals or a reoccurring reversal of sequential portions. Weighting the apertured mask to define at least one Gaussian curve or triangular waveform smooths and eliminates breaks in the compressed or expanded frequencies. Sampling the CCD output at a slower rate than the vertical clock rate compresses the frequency of the representative optical signals and if the CCD output is sampled at a faster rate then the signals will be expanded or rearranged in a sequentially reoccurring order. Thus, the electrooptic processor accomplishes a compression or expansion of signals with the signal's original gross temporal relationship and does not rely upon any mechanica…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.