The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 05, 1977
Filed:
May. 27, 1975
Melvin E Pedinoff, Canoga Park, CA (US);
Hughes Aircraft Company, Culver City, CA (US);
Abstract
There is disclosed a pulse processing method and apparatus for compressing or changing the time scale of signal information represented by the modulation of a pulse of carrier energy which method and apparatus utilizes a crystal through which both a pulse of radio frequency acoustic energy and a pulse of polarized optical energy are simultaneously and colinearly transmitted to scatter energy in the optical pulse from one polarization state into the orthogonal polarization state. The crystal output is thus comprised of two optical pulses. One is the pulse having the original state of polarization and the other is the pulse resulting from the energy scattered to the orthogonal polarization state. The optical energy of rotated polarization is modulated in a fashion reproducing the modulation of the ultrasonic wave by which it is scattered. Furthermore, a short optical pulse can pass through the ultrasonic wave in a time short compared to the duration or length of the ultrasonic wave in the crystalline device. In so doing it reads the modulation of the acoustic pulse and transfers it to a time compressed pulse scale on the scattered optical output pulse. It is shown that the compression ratio is equal to the ratio of the velocity of light divided by the product of the velocity of sound in the crystal times the absolute value of birefringence of the crystal. If both the optical and acoustic pulses are passed through the crystal colinearly and in the same direction, the device takes a time function represented by the acoustic pulse, reverses it in time and compresses it by the ratio of light velocity to sound velocity thus producing a compressed inverse function. If the acoustic pulse and the light pulses are transmitted through the crystal colinearly but in opposite directions, the device takes a time function and without reversing it, compresses it in substantially the same ratio. The device may be applied, for example as a means of improving the signal-to-noise ratio, detection ratio and range resolution in radar systems or the like.