A frequency modulation demodulation device and a control method thereof are provided. The frequency modulation demodulation device includes an input terminal, a phase converter, a phase-locked loop circuit, and a frequency offset/shift detector. The phase converter receives an input signal to obtain a phase signal. The phase-locked loop circuit generates a phase adjustment signal according to the phase signal and adjusts the phase signal according to the phase adjustment signal to perform demodulation of the input signal. The phase-locked loop circuit performs signal alignment and signal compensation on the phase signal to generate a filtered phase signal. The phase adjustment signal provides a feedback of and adjusts the phase signal. The frequency offset/shift detector generates a frequency offset/shift determining signal according to the phase adjustment signal. The frequency offset/shift determining signal is related to a phase frequency offset/shift of the input signal.

A coherent detection-based high-speed chaotic secure transmission method includes: at a transmit terminal in a chaotic secure transmission system, optically coupling an optical chaotic carrier and transmission information by using an orthogonal basis to mask the transmission information by using a noise-like feature of the chaotic carrier, so as to obtain a chaotic masked signal; adding a fast phase disturbance and a fast polarization disturbance to the chaotic masked signal and transmitting the chaotic masked signal over an optical fiber transmission link; and at a receive terminal, obtaining the chaotic masked signal through coherent detection, compensating the chaotic masked signal for linear and nonlinear effects through digital signal processing, and using a polarization orthogonal basis- or phase orthogonal basis-based chaotic decryption algorithm to separate the chaotic carrier from the signal so as to complete decryption.

A frequency modulation demodulation device and a control method thereof are provided. The frequency modulation demodulation device includes an input terminal, a phase converter, a phase-locked loop circuit, and a frequency offset/shift detector. The input terminal receives an input signal. The phase converter is coupled to the input terminal and receives the input signal to obtain a phase signal. The phase-locked loop circuit is coupled to the phase converter to generate a phase adjustment signal according to the phase signal, and the phase-locked loop circuit adjusts the phase signal according to the phase adjustment signal to perform demodulation of the input signal. The frequency offset/shift detector is coupled to the phase-locked loop circuit and generates a frequency offset/shift determining signal according to the phase adjustment signal obtained from the phase-locked loop circuit. The frequency offset/shift determining signal is related to a phase frequency offset/shift of the input signal.

A frequency modulation demodulation device and a control method thereof are provided. The frequency modulation demodulation device includes an input terminal, a phase converter, a phase-locked loop circuit, and a frequency offset/shift detector. The input terminal receives an input signal. The phase converter is coupled to the input terminal and receives the input signal to obtain a phase signal. The phase-locked loop circuit is coupled to the phase converter to generate a phase adjustment signal according to the phase signal, and the phase-locked loop circuit adjusts the phase signal according to the phase adjustment signal to perform demodulation of the input signal. The frequency offset/shift detector is coupled to the phase-locked loop circuit and generates a frequency offset/shift determining signal according to the phase adjustment signal obtained from the phase-locked loop circuit. The frequency offset/shift determining signal is related to a phase frequency offset/shift of the input signal.

An electronic device and a method performed by an electronic device are provided. A number of frequency bands of a plurality of carriers to be used in a plurality of communication circuits for communication is determined. The plurality of communication circuits process carrier signals in different frequency bands. A switching operation, performed by at least one switch, is controlled based on the number of frequency bands and a specified condition that is based on frequency bands able to be processed by an LNA included in each of the plurality of communication circuits. The carrier signals of the plurality of carriers is processed using at least one communication circuit. The at least one switch is alternately connected to two communication circuits and is configured to provide a reception carrier signal from at least one antenna to one of the two communication circuits based on a switching operation.

An electronic device and a method performed by an electronic device are provided. A number of frequency bands of a plurality of carriers to be used in a plurality of communication circuits for communication is determined. The plurality of communication circuits process carrier signals in different frequency bands. A switching operation, performed by at least one switch, is controlled based on the number of frequency bands and a specified condition that is based on frequency bands able to be processed by an LNA included in each of the plurality of communication circuits. The carrier signals of the plurality of carriers is processed using at least one communication circuit. The at least one switch is alternately connected to two communication circuits and is configured to provide a reception carrier signal from at least one antenna to one of the two communication circuits based on a switching operation.

Disclosed are systems, methods, and structures for DSP-free coherent receiver architectures applicable for short-reach optical links. Operationally, a received optical signal is down-converted by mixing it with a local oscillator (LO) laser signal using a 90-degree hybrid followed by balanced photodiodes. Other receiver functions are performed using analog signal processing thereby avoiding power-hungry, high-speed analog-to-digital converters and high-speed digital signal processing. Carrier phase recovery is performed by an electrical phase-locked loop employing a multiplier-free phase estimator stage that—while designed for quaternary phase-shift keying signals—may be employed in designs exhibiting higher modulation formats. Since carrier phase recovery is performed in the electrical domain, LO laser frequency modulation or LO laser integration is not employed. Polarization demultiplexing—if employed—may be performed by the addition of an optical polarization controller prior to the hybrid and may advantageously be realized by cascading multiple phase shifters driven by low-speed circuitry.

Disclosed are systems, methods, and structures for DSP-free coherent receiver architectures applicable for short-reach optical links. Operationally, a received optical signal is down-converted by mixing it with a local oscillator (LO) laser signal using a 90-degree hybrid followed by balanced photodiodes. Other receiver functions are performed using analog signal processing thereby avoiding power-hungry, high-speed analog-to-digital converters and high-speed digital signal processing. Carrier phase recovery is performed by an electrical phase-locked loop employing a multiplier-free phase estimator stage that—while designed for quaternary phase-shift keying signals—may be employed in designs exhibiting higher modulation formats. Since carrier phase recovery is performed in the electrical domain, LO laser frequency modulation or LO laser integration is not employed. Polarization demultiplexing—if employed—may be performed by the addition of an optical polarization controller prior to the hybrid and may advantageously be realized by cascading multiple phase shifters driven by low-speed circuitry.

An electronic device and method for supporting carrier aggregation are provided. An electronic device may include a communication circuit including a plurality of local oscillators; and a processor configured to determine an operation mode of at least one local oscillator among the plurality of oscillators based on at least one of a number of uplink carriers and a number of downlink carriers; and control the at least one local oscillator to operate based on the determined operation mode.

An electronic device and method for supporting carrier aggregation are provided. An electronic device may include a communication circuit including a plurality of local oscillators; and a processor configured to determine an operation mode of at least one local oscillator among the plurality of oscillators based on at least one of a number of uplink carriers and a number of downlink carriers; and control the at least one local oscillator to operate based on the determined operation mode.