7 results about "Quadrature modulation" patented technology

The application discloses a single-channel signal detection design method suitable for a multi-feed antenna, and relates to the field of satellite communication.The method comprises the following steps: S1, a modulator is used to perform orthogonal modulation on multiple-channel signals generated by the multi-feed source, and a combiner is used to form a combined signal; S2, the combined signal is converted into an L-band combined signal by a low-noise down converter (LNB); S3, the L-band combined signal is converted into a zero intermediate frequency baseband digital signal by a tracking receiver; S4, a baseband processing unit is used to complete frequency coarse estimation on the baseband digital signal by using a multi-path parallel frequency search method, so that signal detection is realized; and S5, the baseband processing unit is used to perform frequency coarse correction, FFT frequency offset estimation, phase-locked tracking and power estimation on the signal, so that signal tracking of the multi-feed antenna is completed.The application adopts a code domain synthesis scheme, has low requirements on the antenna feed part of the multi-feed source, can reduce the system cost by using a single-channel receiver, and can improve the reliability of the system.In addition, the multi-path parallel frequency search method is simple in calculation and high in detection precision, and is suitable for signal detection and tracking of a multi-feed antenna system which is cost-sensitive, low in complexity and high in precision.

This invention belongs to the field of optical communication technology and discloses a coherent optical communication system driven by an integrated electro-optic frequency comb, comprising: a continuous wave laser (1), an electro-optic frequency comb chip (2), a radio frequency signal source (3), a radio frequency signal distribution module (4), a first fiber amplifier (5), an arbitrary waveform generator (6), a dual-polarization in-phase quadrature modulator (7), a second fiber amplifier (8), a single-mode fiber (9), a third fiber amplifier (10), a tunable bandpass filter (11), a local oscillator continuous wave laser (12), a coherent receiver (13), and an offline digital signal processing module (14); wherein, the electro-optic frequency comb chip (2) is loaded with a radio frequency signal and can perform electro-optic modulation on the continuous wave optical signal to generate a broadband, flat-top electro-optic frequency comb. By integrating an electro-optic frequency comb chip into the coherent optical communication system, this invention can significantly improve the system integration and greatly reduce the system cost.

The application provides a signal processing method, device, equipment, medium and product, and belongs to the technical field of signal processing. Data flow of a digital baseband signal is separated into a first signal and a second signal, then a first modulation signal and a second modulation signal are respectively generated by combining a first digital carrier and a second digital carrier which are strictly orthogonal through a multiplier in a digital domain, signal synthesis operation is performed by a digital adder to output a first complex signal, and finally the synthesized single data flow is sent into a single digital-to-analog converter to be converted into a first analog signal. In this process, the link which is prone to defects in the orthogonal modulation process is all transferred to the digital domain which is composed of absolute accurate 0 and 1. Since there is no physical direct current bias in the digital domain, and the digital multiplication operation eliminates the parasitic capacitance crosstalk under the high-frequency electromagnetic field, the local oscillator leakage generated when operating with the carrier is directly avoided in the data bottom logic, and the radio frequency signal distortion is avoided.

This invention discloses an optoelectronic fusion millimeter-wave ultra-wideband image suppression receiver device, applied in the field of ultra-wideband communication and radio frequency reception technology. It addresses the problem that existing receiver technologies cannot meet the requirements of multi-band, high-fidelity ultra-wideband reception applications. This invention achieves continuous tuning of the local oscillator frequency from several GHz to hundreds of GHz by independently setting an optically generated local oscillator module with wide tuning capability, adapting to multi-band reception requirements. The multi-wavelength parallel processing capability of the optical comb technology allows for baseband signal extraction without complex channelization. Furthermore, by increasing the signal amplitude through intermediate frequency conversion, it effectively adapts to the driving requirements of electro-optic modulators. Combined with orthogonal mixing and electro-optic quadrature modulation architecture, it achieves excellent image suppression performance. This invention simultaneously solves four core problems: difficulty in adapting large instantaneous bandwidth modulation drives, poor high-frequency local oscillator phase noise performance, poor image suppression effect, and insufficient multi-band adaptability. It has significant engineering application value and technological innovation.

This invention discloses an automatic adjustment control method, system, device, and storage medium for coaxial video signals, comprising the following steps: acquiring an analog coaxial video signal; adjusting the amplitude of a set frequency signal therein so that its gain can be controlled by control parameters to obtain an adjusted analog coaxial video signal; converting the adjusted analog coaxial video signal into a discrete digital coaxial video signal; and extracting a reference level value from the digital coaxial video signal according to the quadrature modulation signal demodulation principle. Beneficial effects: It can match the actual attenuation degree of the coaxial video signal under different transmission distances and cable losses without manual intervention, completely solving the signal problems caused by insufficient or excessive compensation in existing fixed gain schemes, accurately offsetting the amplitude attenuation of high-frequency signals caused by long-distance transmission, and ensuring the brightness edge sharpness and color stability of the decoded video image.

This invention relates to the field of wireless communication technology, and more particularly to an IQ imbalance compensation system based on orthogonal modulation. The system first analyzes the transmitter system circuit topology to identify key imbalance regions and deploys acquisition units. Next, it acquires baseband signals from each region for feature identification, extracting region-level imbalance parameters. Then, based on these parameters, it performs multi-bandwidth interference analysis on the output signal to determine interference parameters. Subsequently, it establishes an adaptive compensation channel, dynamically setting compensation coefficients based on communication scenario requirements, device sensitivity, and channel environment. Finally, it uses these coefficients to perform compensation analysis on the interference parameters, generating adaptive compensation parameters and executing dynamic control. This method, through refined region monitoring and multi-bandwidth analysis, achieves precise compensation that dynamically adjusts according to the scenario, effectively solving the problems of inaccurate positioning and poor adaptability of traditional methods, and significantly improving signal quality and system reliability.

This invention discloses a high-efficiency orthogonal demodulation method and apparatus based on envelope signals. The method, applied at a receiving end, includes: recovering the amplitude and phase based on the envelope information of the orthogonal modulation signal; subtracting the recovered phase from the phase of the low-frequency local oscillator signal used for digital down-conversion to obtain the phase of the baseband signal, thereby achieving equivalent digital down-conversion; and reconstructing the I and Q components of the baseband signal based on the recovered amplitude and the baseband signal phase. This invention significantly simplifies the calculation process and improves processing speed and efficiency.