Browse Prior Art Database

Optical PCM Coder

IP.com Disclosure Number: IPCOM000091708D
Original Publication Date: 1968-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Frei, AH: AUTHOR [+2]

Abstract

This solid-state, word-at-a-time PCM coder converts a wideband signal, e.g., frequency division multiplex, within a communication system. The coder uses light source 1 emitting ribbon-like light beam 2 of about 1 mu m thickness and with a width corresponding to the number of bits to be coded in parallel. The width can be of the order of 300 mu m. Light source 1 preferably emits coherent light in order that the signal-to-noise ratio be kept high. It is turned on by the application of sampling pulses. Light beam 2 is deflected in accordance with an analog value applied to deflection device 3 consisting of birefringent material, e.g., KH(2)PO(4), or the like. After passing device 3, light beam 2 is directed onto reception frame 4 holding optical sensors 5 such as photodiodes or photomultipliers.

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Optical PCM Coder

This solid-state, word-at-a-time PCM coder converts a wideband signal, e.g., frequency division multiplex, within a communication system. The coder uses light source 1 emitting ribbon-like light beam 2 of about 1 mu m thickness and with a width corresponding to the number of bits to be coded in parallel. The width can be of the order of 300 mu m. Light source 1 preferably emits coherent light in order that the signal-to-noise ratio be kept high. It is turned on by the application of sampling pulses. Light beam 2 is deflected in accordance with an analog value applied to deflection device 3 consisting of birefringent material, e.g., KH(2)PO(4), or the like. After passing device 3, light beam 2 is directed onto reception frame 4 holding optical sensors 5 such as photodiodes or photomultipliers. Frame 4 can hold the input ends 6 of optical fibers 7 or other light waveguides. In order to achieve a parallel-to-serial conversion of the light pulses emanating from output ends 8 of fibers 7, the latter have different lengths L1...LN in accordance with the delays required for the respective light pulses. Ends 8 of fibers 7 can be arranged on spherical shell 9 directing the output light pulses onto a common central photoelectric device 10.

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