12 results about "Quadrature modulator" patented technology

This invention belongs to the field of communication and signal processing technology, specifically relating to a GMSK quadrature modulator. It comprises a bidirectional counter, a four-curve data table, an in-phase component processor, and a quadrature component processor, forming a quadrature modulation baseband generator. A binary symbol sequence and a system clock are input to this generator. The system clock is divided to generate a symbol frequency multiplier clock, driving the bidirectional counter to oscillate and count repeatedly. The in-phase and quadrature component processors process and generate curve selection types and curve symbols. The output of the bidirectional counter is used as the curve lookup table address. A quadrature modulation baseband signal is generated by looking up the pre-stored four-curve data table, and then input to a digital up-converter (DUC) circuit to produce a GMSK modulated signal. Compared to existing technologies, this invention is more resource-efficient, has higher accuracy, and lower spurious emissions, making it highly suitable for embedded system or programmable device design and implementation.

The application provides a device and a method for realizing PON rate adjustment based on Polar modulation, and relates to the technical field of passive optical networks.The device comprises a first external cavity laser, a second external cavity laser, a dual-polarization phase quadrature modulator, an arbitrary waveform generator, an erbium-doped fiber amplifier, a single-mode optical fiber, a variable optical attenuator, a coherent receiver and an oscilloscope.The method comprises the following steps: dynamically adjusting the number of information bits A, splicing check bits to form total information bits, optimizing the distribution of information bits and frozen bits according to the optical signal channel sorting result, performing polar encoding on the signal at the encoding end, and mapping the signal into a 16QAM code symbol sequence by using the Polar modulation technology; at the receiving end, calculating the LLR, calculating the path metric value of all paths and performing a pruning operation when the list width reaches a set value, and detecting the L candidate paths by using the CRC check after the decoding is completed.The application realizes flexible regulation and control of the transmission rate of different optical network units.

A signal transmission link and method, a transceiver link, an integrated circuit, and an electromagnetic wave device are disclosed. The signal transmission link is applied in a radar system. The signal transmission link includes: a transmitting baseband digital module, a digital-to-analog converter (DAC) module, a transmitting local oscillator, and a transmitting quadrature modulator. The DAC module includes two identical DACs. The transmitting baseband digital module is configured to generate two orthogonal transmitting digital baseband signals and send the two orthogonal transmitting digital baseband signals to one DAC respectively. The DAC module is configured to convert the two orthogonal transmitting digital baseband signals into two transmitting analog baseband signals. The transmitting local oscillator is configured to provide a transmitting local oscillator signal. The transmitting quadrature modulator is configured to perform frequency shifting and phase shifting operations on the transmitting local oscillator signal based on the two transmitting analog baseband signals to form a predetermined phase-shifted FMCW radio frequency transmission signal.

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.

An over-the-air measurement system for testing a device under test is provided. The over-the-air measurement system includes at least two quadrature modulators and at least two antennas. Each of the antennas is connected to a dedicated quadrature modulator, thereby establishing at least two measurement modules. The at least two quadrature modulators are rotated with respect to each other, thereby providing different measurement polarizations of the at least two measurement modules with respect to a common reference plane.

A transmitter includes: processing circuitry which, in operation, performs correction processing on a first signal of a pair of transmission signals mapped to frequency resources symmetric with respect to a center frequency by using a second signal of the pair of transmission signals; and a quadrature modulator which, in operation, performs quadrature modulation on the pair of transmission signals after the correction processing.

To improve the performance of radio communication.SOLUTION: The transmitter includes a processing circuit that uses one of the transmission signals mapped to the symmetric frequency resources with respect to the center frequency to perform correction processing on the other of the transmission signals mapped to the symmetric frequency resources, and a quadrature modulator that performs quadrature modulation on the transmission signal after the correction processing.SELECTED DRAWING: Figure 5

The application discloses a physical layer security waveform generation method, comprising the following steps: step 1, obtaining and constructing a symbol-related prime set and a chip-related prime set; step 2, processing the symbol-related prime set and the chip-related prime set respectively to obtain a symbol vector and a chip vector; step 3, performing point multiplication operation on the symbol vector and the chip vector to obtain a signal vector; step 4, filtering the signal vector as an input through a baseband shaping filter; and step 5, moving the filtered result to a corresponding frequency point through a quadrature modulator to obtain a final result. The method obtains the concealment characteristics of the waveform and the security characteristics of the transmission information based on randomization time-varying physical layer waveform parameters, and can obtain a short-time stable data transmission rate, thereby meeting the actual requirements of a wireless communication system.

The invention discloses a broadband microwave vector signal source system and an implementation method thereof, relates to the technical field of microwave signals, and is characterized in that a digital technology and an analog technology are combined, a digital modulation signal is generated by utilizing an FPGA (Field Programmable Gate Array), and a fixed quadrature modulation analog output signal is generated through a DAC (Digital-to-Analog Converter) (containing a quadrature modulator); according to the broadband microwave vector signal source system, the frequency of the broadband microwave vector signal source system is reduced, the frequency of the broadband microwave vector signal source system is reduced, the frequency of the broadband microwave vector signal source system is increased, the frequency of the broadband microwave vector signal source system is increased, the frequency of the broadband microwave vector signal source system is increased, and the consistency of indexes is well guaranteed.

A radio frequency (RF) transceiver includes a reference signal source to generate a reference signal, a local RF source to generate a local RF signal, and a mixed signal phase / frequency detector to compare the reference signal to the local RF signal and generate a difference signal from the comparison, wherein the difference signal includes a modulation component and an error component. The transceiver further includes a receiver front end to receive an angle modulated RF signal and downconvert the angle modulated RF signal to a baseband signal, and a quadrature modulator configured to angle modulate the reference signal source with the baseband signal.

The utility model provides a transmitting terminal unit and a multi-carrier wireless communication system, and the transmitting terminal unit comprises an optical comb signal generation module which is used for generating an optical comb signal and outputting the optical comb signal to a wavelength division multiplexer; the orthogonal frequency division multiplexer outputs signals to the first rectangular filter and the second rectangular filter, the first rectangular filter outputs signals to the first orthogonal modulator, the first orthogonal modulator outputs modulated signals to the first dual-port Mach-Zehnder modulator, and the second dual-port Mach-Zehnder modulator outputs modulated signals to the second dual-port Mach-Zehnder modulator. The first dual-port Mach-Zehnder modulator outputs a signal to the Gaussian filter; the second rectangular filter outputs a signal to a second quadrature modulator, the second quadrature modulator outputs the modulated signal to a second dual-port Mach-Zehnder modulator, and the second dual-port Mach-Zehnder modulator outputs a signal to a third rectangular filter; and the Gaussian filter output signal and the third rectangular filter output signal are used for outputting filtered signals to the first combiner. The multi-carrier wireless communication system is provided with the transmitting terminal unit. According to the utility model, the efficiency of optical signals can be improved.

In some implementations, a controller may apply a set of phase dithers to a first inner Mach-Zehnder (MZ) interferometer and a second inner MZ interferometer, the first inner MZ interferometer and the second inner MZ interferometer being included in an outer MZ interferometer, the set of phase dithers including a first in-phase dither state and a second in-phase dither state and including a first anti-phase dither state and a second anti-phase dither state. The controller may determine an initial error term based at least in part on the set of phase dithers. The controller may adjust, based on the initial error term, the outer MZ interferometer to a target phase associated with a target error term, wherein respective branches of at least one of the first MZ interferometer or the second MZ interferometer are adjusted differentially.