Keying

About: Keying is a research topic. Over the lifetime, 6598 publications have been published within this topic receiving 82943 citations.

Electronic keying scheme for locking data

Abstract: A data locking system which modifies data in accordance with a renewable key variable derived from the exclusive ORing of a pseudorandom combination number from an external source means with an altered key variable.

Spectral efficiency of coded phase-shift keying for fiber-optic communication

Abstract: Several optical modulation and detection schemes are compared by computing their spectral efficiencies over additive white Gaussian noise channels. The bandwidth savings of differential quadrature phase-shift keying (D-QPSK) over both direct-detection on-off keying and differential binary phase-shift keying suggest that D-QPSK can improve the reach and efficiency of wavelength-division multiplexing systems. To test the theory, Reed-Solomon and low-density parity-check forward error correction codes are designed and evaluated. The codes generally behave as expected, except that for D-QPSK the gains are hampered by the differential detector. It is further shown that neither multiple-symbol differential detection nor decision-feedback detection is attractive when using strong codes.

54 Gbit/s OOK transmission using single-mode VCSEL up to 2.2 km MMF

Abstract: Successful 54 Gbit/s on–off keying (OOK) transmission over 2.2 km of multimode OM4 fibre is demonstrated. The decisive advantages of the single mode over multimode vertical cavity surface emitting laser (VCSEL) in transmission experiments are shown.

Light mountable on a mounting rail

Abstract: Mounting arrangement (50) includes clamping arrangement (50), or keying arrangement (60), or both. Clamping arrangement (50) includes fixed clamp member (52) and movable clamp member (54) that is movable towards and away from fixed clamp member (52) and is biased (58) towards fixed clamp member (52), so as to grip mounting rail (200) therebetween. Keying arrangement (60) employs interchangeable keying members (62) that may be disposed in recess (42) and that may have different keying features (64) for use with different mounting rails. Circuit structure (300, 300') for light (10) includes first and second circuit portions (310, 330) in different planes, first circuit portion (310) having a peripheral shape corresponding to the shape of mounting surface(48), and second circuit portion (330) including switch (106) for selectively energizing light source (360).

Wireless internet access system and method

Abstract: A wireless Internet access system and method supports the transmission and reception of multiple types of traffic between mobile subscriber units and existing networks. A frame structure is used that can support the transmission of multiple types of traffic and adapt to changes in the traffic types needed and the amount of data for a particular traffic type. In addition, data transmission is performed using orthogonal frequency division multiplexing and differential phase shift keying to avoid intersymbol interference. Receiving units in the mobile subscriber units and existing networks include antenna arrays to provide a multipath transmission.