Keying

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

Burst frequency shift keying data communication system

Abstract: A communications system for transmission of low density digital data from a plurality of transmitters to a common receiver. It is a burst-mode frequency shift keying (FSK) communication system useable with a master antenna television (MATV) system that minimizes mutual interference between outputs of a large number of transmitters individually located with TV sets. The transmitters are combined with converters for transmission of programs through the system to individual TV sets as controlled by the users, and with information such as TV channel in use, room number identification, and specialized information such as completion of maid service, fire, and burglary alarms transmitted back through the system. In one system the transmitters use a carrier frequency of 12MH z , a frequency at the lower end of the passband of a coax system with FSK modulation at an equivalent switching rate of 20KH z and modulation index of 5 accepting a RF channel loading of up to 700 simultaneous users.

Dispersion-tolerant transmission using a duobinary polarization-shift keying transmission scheme

Abstract: We demonstrate a novel dispersion-tolerant transmission scheme based on a three-level duobinary-encoded polarization-shift keying (PoISK) transmission format. Simulations over standard single-mode fiber demonstrate an improvement in the chromatic dispersion-limited transmission distance from /spl sim/65 km, using conventional nonreturn to zero intensity modulation to /spl sim/195 km for duobinary PoISK.

Direct detection differential polarization-phase-shift keying based on Jones vector

Abstract: In this paper, differential polarization-phase-shift keying (DPolPSK) is proposed for digital lightwave communication, in which information is encoded in both polarization and phase. The DPolPSK symbols are demodulated by optical delayed interference and electrical multilevel detection, without using any polarization control or polarization selection at the receiver. Simulation results show that single-channel error-free transmission at 20 Gb/s (10 Gsymbol/s) through 25 spans of 100 km standard single-mode fiber is possible. Unlike for DPSK, the Gaussian BER estimation method is found to be reasonably accurate for this new modulation format. The constellation diagram of DPolPSK can be represented by a set of Jones vectors. Hence DPolPSK can also be called differential Jones-vector shift keying (DJSK).

Color-Shift Keying for Optical Camera Communication Using a Rolling Shutter Mode

Abstract: An optical camera communication (OCC) is a special type of a visible light communication that uses a complementary metal-oxide semiconductor as a receiver. However, it is difficult to apply a high-order modulation scheme to such communications because of strong intersymbol interference. In this paper, we propose and demonstrate an OCC system using an 8-color color-shift keying scheme. We used an RGB-based LED light panel as a transmitter and analyzed the properties of the rolling shutter. We discuss the demodulation process and perform bit error rate (BER) tests at different ambient illuminances and sampling positions. A net data rate of 8.64 kbps and a pixel efficiency of 3.75 pixels per bit were achieved while keeping the BER below 3.8E-3, which meets the FEC's 7% forward error correction requirement. In addition, the system shows good robustness for indoor applications.

Performance of coherent optical polarization shift keying modulation in the presence of phase noise

Abstract: The performance of optical coherent modulation schemes using the state of polarization of light as the modulating parameter (POLSK, POLarization Shift Keying) is analyzed, in the presence of laser phase noise. First, we compare three different analysis methods to account for the effects of phase noise in the binary case, and choose the one offering the best trade-off in terms of accuracy/complexity. Successively, we derive a tight upper bound to the performance of multilevel POLSK systems with postdetection filtering. Then, we include phase noise using the best method as tested in the binary case and extensively discuss the performance of binary and various multilevel POLSK constellations, optimized with respect to the IF filter bandwidth. The results show that binary POLSK has a very low sensitivity to phase noise and that multilevel POLSK is even less sensitive than the binary scheme. >