Keying

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

Encoding device and method and decoding device and method

Abstract: An encoding device in a data transmission/reception system includes a first convolutional encoder that encodes an outer code, an interleaver that permutes input data, a second convolutional encoder that encodes an inner code, and a muti-level modulation mapping circuit that performs signal-point mapping based on eight-phase shift keying. When the encoding device uses the second convolutional encoder having two or more memories, the first convolutional encoder uses, as the outer code, a code with a minimum output distance greater than the maximum input distance at which the minimum-distance inner code is generated.

Photonic generation of microwave frequency shift keying signal using a single-drive Mach–Zehnder modulator

Abstract: We propose and experimentally demonstrate a new scheme for photonic generation of microwave frequency shift keying (FSK) signal by employing one single-drive Mach-Zehnder modulator (MZM) In the proposed method, an electrical signal with different radio frequency (RF) amplitudes and direct current (DC) components for bit '0' and bit '1' is generated After amplification, the signal is fed into a single-drive MZM which is biased at the quadrature and null points of its transmission curve for bit '0' and bit '1', respectively Due to the different RF amplitudes, a microwave FSK signal can be obtained after photodetection, where the space frequency is the same as the RF frequency and the mark frequency is twice as large as the RF frequency The feasibility of the proposed scheme is verified by a proof-of-concept experiment 5/10-GHz and 10/20-GHz microwave FSK signals with different bit rates are successfully demonstrated

Digital coherent phase demodulator

Abstract: A digital system for demodulating coherent phase shift keyed signals. Maximum likelihood estimates of the unmodulated phase and rate of change of the unmodulated phase of the received signal relative to a local oscillator signal are used to improve the demodulation process. The maximum likelihood estimates are obtained from measurements of the phase of the received signal relative to the local oscillator signal over a predetermined set of keying intervals. The digital demodulation process permits rapid "lock-on" at low signal-to-noise ratios.

Design of Visible Light Communication Receiver for On-Off Keying Modulation by Adaptive Minimum- Voltage Cancelation

Abstract: In this paper, a new design of visible light communication (VLC) receiver for on-off keying (OOK) modulation is proposed. The design is based on the cancelation of minimum offset voltage of the received OOK signal, using a novel minimum-voltage detection circuit. This circuit is capable of tracking the minimum voltage of an input signal even if its value increases with time. Experimental results show that the proposed receiver is immune to the interference from sunlight and indoor fluorescent lights.

A polarization shift-keying system for underwater optical communications

Abstract: A compact and simple setup for testing polarization modulation in the underwater channel is demonstrated. The results from this system compare favorably to a non-polarization modulation system utilizing on-off keying modulation. This system will allow future work to explore using polarization in optical communication systems underwater. The advantages of such systems include ability to monitor the water quality of the channel during transmission and reduction of receiver shot noise.