17 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.

The present invention discloses a secure communication method and system based on chaotic prediction and interleaving coding in a reserve pool. The chaotic encryption module includes a light source output by a first continuous wave laser (CW), which is modulated by a parallel quadrature modulator (IQM) to convert the signal output by an arbitrary waveform generator (AWG) for transmission. The signal is pseudo-randomly interleaved and encoded. The transmitted signal is loaded onto a chaotic carrier through a first optical coupler (FC) to achieve chaotic hiding. The chaotic optical carrier is then transmitted through an information transmission module. The chaotic optical carrier is predicted in advance by the reserve pool in the chaotic decryption module and modulated onto the continuous optical carrier output by a second continuous wave laser (CW) through a Mach-Zehnder modulator (MZM). The signal is then decrypted by a 90° mixer to initially restore the original transmitted signal. Finally, the resulting signal is processed by a local oscillator (LO) and a coherent receiver, and digital information processing (DSP) is performed to compensate, recover, and decrypt the digital signal, thereby realizing chaotic secure coherent optical communication.

A balanced power amplifier includes a first power amplifier configured to apply a first gain having a first predetermined magnitude and a first programmable phase adjustable phase to generate a first amplified signal, the first programmable phase being adjustable to either a first phase or to a second phase that is 180° phase shifted relative to the first phase; a second power amplifier configured to apply a second gain having a second predetermined magnitude and a second programmable phase to generate a second amplified signal, the second programmable phase being adjustable to either the first phase or to the second phase; and a 90° hybrid coupler configured to receive the first amplified signal and the second amplified signal and generate and output a first output signal or a second output signal based on a combination of the first amplified signal and the second amplified signal.

The invention relates to a digitally-controlled quadrature modulation laser single side band frequency shift and phase locking device and method, a field programmable logic gate array of the device is connected with four digital-to-analog converters, every two digital-to-analog converters are connected with a quadrature modulator, the two quadrature modulators are also connected to an optical quadrature modulator, and the optical quadrature modulator is connected with the four digital-to-analog converters. The output of the laser source realizes single side band frequency shift through an optical quadrature modulator, part of optical signals are converted into electric signals through a third beam splitter, and parameters of the optical modulator are adjusted in real time through a voltage control port. And the other path of laser is interfered with the frequency-shifted optical signal in the beam combiner through the first beam splitter, demodulated by the orthogonal down-conversion mixer, fed back with phase information, and transmitted back to the field programmable logic gate array through the three-channel analog-to-digital converter to form closed-loop control. According to the invention, the influence of sideband signals generated by adjustment is reduced; moreover, the frequency shift bandwidth can be higher, the influence of a spatial light path is reduced, and the stability is improved.

The present invention relates to the field of clock synchronization, and more specifically to a broadband arbitrary reference adaptive clock synchronization device. An input signal is amplified and shaped to generate two signals. One signal is sent to an FPGA, and the other is sent to an orthogonal power splitter. The mixed signal is then mixed with a local oscillator signal through an orthogonal modulator to generate a mixed signal. The mixed signal is then passed through a fixed frequency divider to generate a frequency-divided signal. This mixed signal is then phase-detected with a DDS output signal to generate an error voltage, which is then passed through a low-pass filter to control a crystal oscillator. The crystal oscillator's output is passed through a coupler to generate two signals. One signal serves as the global system clock, and the other signal is passed through a fixed frequency multiplier to obtain a multiplied signal. The multiplied signal passes through a filter amplifier and then to a power splitter. The power splitter splits the multiplied signal into two signals. One signal serves as the reference clock and generates a corresponding frequency point under the control of the FPGA to generate an output signal. The other signal is passed through an amplifier and serves as the local oscillator signal of the orthogonal modulator. The present invention is suitable for adaptive clock synchronization devices.

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.

The invention relates to the field of clock synchronization, in particular to a broadband arbitrary reference adaptive clock synchronization device. An input signal is amplified and shaped to generate two paths of signals, one path of signals is sent to an FPGA, the other path of signals is sent to an orthogonal power divider and then is mixed with a local oscillator signal through an orthogonal modulator to obtain a frequency mixing signal, the frequency mixing signal passes through a fixed frequency divider to obtain a frequency division signal, the frequency division signal and a DDS output signal are subjected to phase discrimination to generate error voltage, and the error voltage passes through a low-pass filter to control a crystal oscillator. The output of the crystal oscillator passes through the coupler to generate two paths of signals, one path is used as a global system clock, the other path passes through the fixed frequency multiplier to obtain a frequency-doubled signal, the frequency-doubled signal passes through the filter amplifier to the power divider, the power divider divides the frequency-doubled signal into two paths of signals, one path is used as a reference clock, and the other path is used as a reference clock; a corresponding frequency point generation output signal is generated under the control of the FPGA, and the other path of signal is used as a local oscillator signal of the quadrature modulator after passing through the amplifier. The invention is applicable to the self-adaptive clock synchronization device.

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.