Telefonaktiebolaget Lm Ericsson (Publ)

Benedek Kovács

Zsolt Kenesi

Gabor Nemeth

János Ladvánszky

Zsolt Kis

Márton Czermann

Sándor Jókai

László Bacsárdi

Kornél KOMÁROMI

Zoltán Elzer

Quantum key distribution, QKD, transmitter apparatus including a beam splitter configured to receive an initial pulse train of optical pulse pairs, a first photodetector, an optical storage line, a phase modulator, a polarisation rotation mirror, a second photodetector and processing circuitry configured to:

Auto compensated quantum key distribution transmitter, receiver, system and method

A demodulation system for demodulating an input signal is provided. The input signal includes a carrier wave modulated with data symbols selected from a plurality of candidate complex symbol values. The system includes a carrier recovery module, operative to compensate for a carrier frequency of the carrier wave and output a demodulated data signal. The carrier recovery module includes: a first complex-signal conversion module, operative to convert the input signal into a complex-valued input signal; a voltage-controlled oscillator; a mixer, for mixing the complex-valued input signal and a complex-valued output signal of the voltage-controlled oscillator, and generating a mixer output signal; a low-pass filter, coupled to the mixer, operative to filter the carrier frequency from the mixer output signal, and output a signal corresponding to the demodulated data signal; and a folding module, operative to apply a folding algorithm to the output signal of the low-pass filter.

Methods and apparatus for signal demodulation

A technique for transmitting data is described. The data is represented by a modulation symbol comprising an in-phase component and a quadrature component. Considering a method aspect of the technique, the modulation symbol () is split into at least two different baseband signals (), which are in phase with each other and jointly representative of the modulation symbol (). The at least two baseband signals () are up-converted from a baseband frequency to a transmission frequency. Each of the at least two up-converted signals () is transmitted on a different physical channel ().

Technique for coherent data communication

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Budapest, Hungary

Benedek Kovács