Keying

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

Coherent detection of phase-shift keying signals using digital carrier-phase estimation

Abstract: We describe a phase-diversity optical homodyne receiver for demodulating M-array phase-shift keying (PSK) signals, which is based on digital carrier-phase estimation. Bit-error rate measurements in 2-, 4- and 8-PSK systems are demonstrated with such receiver.

Vehicle mounting apparatus of an automatic vehicle location system

Abstract: A vehicle mounting apparatus for an automatic vehicle location system having a omni-directional antenna, a transmitting and receiving switch, an oscillator frequency converters, a frequency-shift keying demodulator, post office committe standard associate group decoder, a pseudorandom noise signal generator, a phase-shift keying modulator, a transmitting signal generator, a power amplifier, and a power supplier. The vehicle mounting apparatus receives a referencing signal from a control center and transmits an answer signal relating to location of a vehicle to be located.

Coherent Digital Polarization Diversity Receiver for Real-Time Polarization-Multiplexed QPSK Transmission at 2.8 Gb/s

Abstract: This letter presents a coherent digital polarization diversity receiver for real-time polarization-multiplexed synchronous quadrature phase-shift keying transmission with distributed feedback lasers at a data rate of 2.8 Gb/s. The tolerance against fast polarization changes and polarization-dependent loss is evaluated for different filter widths in the carrier recovery circuit. The minimum achieved bit-error rate is 3.4 times 10-7.

A Stream Cipher Based on Linear Feedback over GF(28)

Abstract: Embedded applications such as voice encryption in wireless telephones can place severe constraints on the amount of processing power, program space and memory available for software encryption algorithms. Additionally, some protocols require some form of two-level keying which must be reasonably fast. This paper introduces a mechanism for creating a family of stream ciphers based on Linear Feedback Shift Registers over the Galois Finite Field of order 2n, where n is chosen to be convenient for software implementation. A particular stream cipher based on this methodology, SOBER, is presented and analysed.

Virtual studio system

Abstract: A method of providing a visual representation of a scene to a participant in a studio is provided, wherein the studio is arranged to be viewed by a camera to provide a camera image and has at least a portion of a background object arranged to be keyed out of the camera image by a keying process. The method includes obtaining an estimate of the viewpoint of the participant; rendering an image of the scene based on the viewpoint of the participant; and projecting at least a portion of the rendered image onto the background object to provide a projected image portion visible to the participant. The projected image portion is projected so as to be keyed out of the camera image by the keying process.