240results about "Optical transmission for RF signal generation/processing" patented technology

Aspects of the disclosure relate generally to a circuit for sustaining an radio frequency (RF) modulated optical signal. The circuit may comprise a self injection locking component having a fiber optic delay line over which a portion of the optical signal propagates. The circuit may also comprise a self phase locked loop component having at least two fiber optic cables having different lengths and over which another portion of the optical signal propagates and a phase detector coupled to the at least two fiber optic cables and configured to determine a phase difference between the signals propagating over one of the respective fiber optic cables. The circuit may further comprise a voltage controlled oscillator configured to generate a stable oscillating signal in response to signals generated by each of the self injection locking and self phase locked loop components, the stable oscillating signal being configured to sustain the optical signal.

An electromagnetic transmission and reception system comprises a transmitter section and a receiver section. The transmitter section has a first signal source, a second signal source at a lower frequency than the first signal source, and means for generating from the first and second signal sources a plurality of signals with fixed frequency spacing derived from the second signal source frequency. One or more pairs of the plurality of signals are selected, and for the or each pair, the signals of the pair are combined to derive an output signal having a frequency derived from the difference between the frequencies of the signals of the pair. The receiver section combines a received signal, which comprises a received version of the output signal, with a local oscillator signal for frequency down-conversion of the received signal. This local oscillator signal is generated by the transmitter section. This provides a system in which the generation of signals of the desired frequency is achieved by mixing signals of specific frequencies. The reception uses frequency down-conversion using the same signal sources as used for the transmission. This enables a low noise system to be implemented.

An RF channelizer comprising: a master laser for generating a reference beam; a splitter for splitting the reference beam into first and second beams; first and second modulator modules for converting the first and second beams into first and second modulated beams; first and second seed tone generators for deriving first and second seed tones; first and second parametric mixers for converting the first and second seed tones into first and second combs; a signal modulator for modulating a received RF signal onto the first comb; first and second optical filters for separating the first and second combs into pluralities of first and second filtered beams with center frequencies corresponding to the second comb lines; and a coherent detection array for selecting, combining, and detecting corresponding pairs from first and second filtered beams providing at the output a contiguous bank of channelized signals covering the bandwidth of the RF signal.

A frequency tunable terahertz continuous wave generator controls the number of feedbacks of an optical signal output from an optical intensity modulator by adding a feedback loop between input and output terminals of the optical intensity modulator, thereby simply tuning a frequency of a terahertz continuous wave.

A communications device includes a transmitter device having an optical source configured to generate an optical carrier signal, a first E/O modulator coupled to the optical source and configured to modulate the optical carrier signal with an input signal having a first frequency, and a second E/O modulator coupled to the optical source and configured to modulate the optical carrier signal with a reference signal. The communications device includes an optical waveguide coupled to the transmitter device, and a receiver device coupled to the optical waveguide and including an O/E converter coupled to the optical waveguide and configured to generate an output signal comprising a replica of the input signal at a second frequency based upon the reference signal.

Systems and methods for precision phase noise measurements of radio frequency (RF) oscillators are provided. An RF signal under test can be modulated on a continuous wave (cw) laser carrier frequency via generation of modulation sidebands using an appropriate modulator. A photonic delay line can be implemented as a self-heterodyne detection system for the phase noise, allowing for photonic down-conversion of the phase noise measurement to direct current (DC). The self-heterodyne detection system allows detection outside of any 1/f noise issues. Ultra-low phase noise detection for RF frequencies in a range from below 1 GHz to beyond 100 GHz is enabled with a low noise floor in the whole frequency range. Higher-order modulation sidebands can further reduce the noise floor of the system. Ultra-low noise RF (microwave) output can be generated. The RF signal under test can be generated by a dielectric resonance oscillator or opto-electronic oscillator.

A receiver architecture for physically-assisted computing of transforms, such as discrete Fourier transforms (DFT) and discrete Hilbert transforms (DHT), employs mutually-coherent optical frequency combs for detection of the coherent beating between an optical signal and a reference optical tone generated by a local oscillator (LO). A signal replication mixer generates a plurality of signal optical tones having a frequency pitch with an input signal mapped thereon. A reference mixer (local oscillator) generates a plurality of reference optical tones having an offset frequency pitch relative to the signal tones. A receiver backplane detects coherent beating between the signal optical tones and the reference optical tones. The input signal may be in the optical domain or in the radio-frequency domain.

The present invention is to provide an optical modulating system for generating a signal of a frequency (f₀+2f_m) and a signal of a frequency (f₀−2f_m) and suppressing a signal of a frequency (f₀) by a DSB-SC modulator.

A fourth harmonic generating system for solving the above problem comprises a first DSB-SC modulator (2) a second DSB-SC modulator (3) and a signal control section (5) for controlling a modulating signal from a signal source (4) for generating modulating signals applied to the first and second DSB-SC modulators (2,3) so that a lower side-band signal (f₀) generated by modulating the upper side-band signal of the DSB-SC modulator (2) by the DSB-SC modulator (3) and an upper side-band signal (f₀) generated by modulating the lower side-band signal of the DSB-SC modulator (2) by the DSB-SC modulator (3) cancel each other.

An analog signal receiver includes photonic sampling and electronic quantization. The receiver includes timing control circuitry configured to receive a series of optical pulses and output a plurality of timing signals based on the series of optical pulses to synchronize optical switches that receive a sampled optical signal to time deinterleave the optically sampled signal. The time deinterleaved signals are then sent to a plurality of demodulators wherein each demodulator receives at least one time deinterleaved optically sampled signal and at least one time deinterleaved optical reference signal to produce electrical signals based on the demodulated optical signals.

The present invention provides a wideband modulated signal generating device capable of realizing an always stable operation and obtaining an intended wideband modulated signal in spite of a shift in the optimal bias voltage due to DC drift occurring in an optical intensity modulation section. In the wideband modulated signal generating device, a DC power supply control section 50 controls a first DC power supply 51 and a second DC power supply 52 for applying first and second bias voltages to an optical intensity modulation section 30 based on a signal level detected by a level detecting section 70, and controls a third DC power supply 53 for applying a third bias voltage to an optical intensity modulation section 30 based on a distortion level detected by a distortion level detecting section 81, thus compensating for a shift in the optimal bias voltage occurring due to DC drift.

An apparatus for generating a frequency spectrum of an RF signal comprising a gate switch for generating a series of pulses from a laser of wavelength lambda modulated by an input RE signal, a first fiber optical loop for circulating a first percentage of a first pulse of the series of pulses from the gate switch, for a predetermined number of cycles n where each cycle takes time t1, a second fiber optical loop for conducting a second percentage of the first pulse for predetermined number of cycles “k”, where each cycle takes time t2, where t2*k=t1*n, a first switch with a first state for coupling the first pulse from the gate switch to a coupler, the coupler coupling the first pulse into the first fiber optical loop and tapping replicas of the pulse from the first fiber optical loop, and a second state for coupling the second percentage of the first pulse to the coupler to increase intensity of the tapped replica pulses, a processor for correlating the replicas of the pulse with each other to produce a set of data points comprising a plurality of multiplexed correlated pulses and transforming the data points into a channelized frequency spectrum of the input RF signal.

The invention discloses a photon microwave down conversion device and method, and belongs to the technical field of microwave signal processing. In the device, an electro-optic modulator, an optical narrow band notch filter, a photoelectric detector and an electric mixer form an oscillating loop, the device has a function of generating microwave local oscillation, and the frequency of a local oscillation signal can be flexibly adjusted by changing the frequency of output optical waves of a variable length adjustable laser. Due to a phase modulation function of the electro-optic modulator, a radio frequency signal is output from an output end of the down conversion photoelectric detector, thus having complete radio frequency isolation advantages. The down conversion device has flexible regulation and control ability, can not only perform down conversion on the radio frequency signals with different frequency to intermediate frequency signals with the same frequency, but also can performdown conversion on the same radio frequency signal to the intermediate frequency signals with different frequency. The photon microwave down conversion device solves the problems of complex structure, poor radio frequency isolation, flexible tuning difficulty and the like of microwave down conversion in the prior art.

A wide band digital RF receiver includes an RF front end configured to convert a RF signal into an IF signal. A wide band digital receiver also includes a photonic Analog-to-Digital Converter (pADC), and a digital processor. The pADC includes a photonic sampler that phase-encodes a stream of optical pulses with the IF signal to obtain phase-encoded optical pulses, and that amplitude-encodes an identical stream of optical pulses with the IF signal to obtain amplitude-encoded optical pulses. The pADC also includes a photonic processor and an electronic quantizer. The photonic processor processes the phase-encoded optical pulses by way of an I channel and a Q channel, and processes the amplitude-encoded optical pulses by way of an amplitude channel.

A waveguide assembly for a use with, for example, a microwave receiver. The waveguide assembly includes: a waveguide; a tapered structure disposed within the waveguide, the tapered structure tapering in thickness from a first end with a zero height to a second end where the tapered structure has a height which nearly fills, but does not completely fill, the waveguide, to thereby define a modulator receiving space between the tapered structure and an adjacent wall of said waveguide. The second end of the tapered structure is preferably disposed adjacent an open circuited end of the waveguide. An electro-optic modulator is disposed on a dielectric substrate, the dielectric substrate being disposed at least partially within the modulator receiving space and the electro-optic modulator being disposed so that it is located, in use, at an antinode of a standing wave of the waveguide assembly.

A filter and a method of filtering a high frequency electrical signal using photonic components is disclosed. The filter has a serially fiber-coupled laser source, a modulator, a filter, and a photodetector. The electrical signal is applied to the modulator. The modulated light propagates through the filter which is constructed to pass not only a modulated sideband, but also at least a fraction of light at the carrier frequency of the laser. The photodetector detects a signal at the beat frequency between the carrier and sideband signals, after both signals have propagated through the filter. As a result, a separate optical branch for light at the carrier frequency is not required, which considerably simplifies the filter construction and makes it more stable and reliable.

The invention relates to a distributed antenna system, method and device. The distributed antenna system comprises a digital-to-analog expansion unit and a far-end cascade chain. The far-end cascade chain comprises a plurality of far-end units which are in cascade connection through radio frequency cables, and the head-stage far-end unit of the far-end cascade chain is connected with the digital-to-analog expansion unit through the radio frequency cables. And the digital-to-analog expansion unit is used for carrying out baseband processing operation on the received external signal and carrying out mutual conversion operation on the analog radio frequency signal and the digital radio frequency signal. Based on this, the digital-to-analog expansion unit and the remote unit adopt a daisy chain topological structure based on cable connection, so that the cost of a transmission link can be effectively reduced while the transmission bandwidth is improved. Moreover, the digital-to-analog expansion unit executes baseband processing, and the far-end unit does not need baseband processing equipment, so that the device cost and the operation power consumption of the system can be effectively reduced. The system has the characteristics of supporting multi-mode and multi-frequency, cell splitting and the like, and is easy to expand the capacity and low in construction difficulty.

A method of and system of processing a phase-modulated optical signal includes performing, by demodulators, demodulation of the phase-modulated optical signal and outputting optical demodulated signals. The processing further includes performing, by pairs of gated photo detectors respectively connected to the I/Q demodulators, photo detection of the demodulated signals. The processing further tracks and holds electronicversions of the demodulated signals with a track and hold amplifier.

A detection system includes a photonic module, a radio frequency (RF) module and processing circuitry. The photonic module may be configured to generate an optical tone for modulation in an optical domain prior to conversion to the RF domain. The RF module may be configured to interface with the photonic module to receive a transmission signal converted from the optical domain. The processing circuitry may be configured to interface with the photonic module and RF module to enable an operator to control of the photonic module and the RF module at least with respect to selectively determining a carrier frequency of the optical tone and a modulation technique to be employed with respect to the transmission signal converted from the optical domain.

The invention provides a beamforming (BF) weight assigning method and a BF weight assigning device, used for reducing power dividing insertion loss of the BF, and avoiding electromagnetic interference between a power dividing network and each base band port-antenna unit channel. The device provided by the embodiment of the invention comprises M optical carrier modules, M electro-optical modulation modules, M optical delay modules, a branch wavelength division multiplexer (WDM), N photovoltaic conversion modules, and an antenna array with a k*N antenna unit, wherein M and N are integers more than or equal to 1; the optical carrier modules are used for generating N optical carriers with different wavelengths; the electro-optical modulation modules are used for modulating electrical signals to the optical carriers to acquire a modulated optical signal; the optical delay modules are used for adjusting delay of the modulated optical signal; the branch WDM is used for shunting according to the wavelength of the modulated optical signal after the delay is adjusted to acquire N optical sub-signals; the photovoltaic conversion modules are used for converting the N optical sub-signals into N electric sub-signals; and the antenna array is used for forming a plurality of beams with adjustable direction according to N radio frequency electric signals.

This invention discloses a photonic system to beamform the electric field yield by a phased array antenna. The system function relies on a photonic tunable delay line, which consists on an optical Mach-Zehnder interferometer with a predefined time delay difference between arms. The time delay is tuned by adjusting the coupling ratio between the power applied to each one of the interferometer's delay lines. Three embodiments are proposed, wherein one of them just uses a single delay line and a single monchromatic light source, independently of the quantity of the array elementary antennas.

The invention relates to a method for manufacturing a filter containing single-crystal piezoelectric radio-frequency (RF) resonators. The method comprises the following steps: acquiring one removablecarrier with a releasing layer; manufacturing a piezoelectric film on the releasing layer; depositing a first electrode layer on the piezoelectric film; manufacturing a back film on a silicon cover; attaching a wafer back film onto an electrode; separating the removable carrier; necessarily measuring piezoelectricity and modification; selectively corroding the piezoelectric film to form an island;corroding a coating and a silicon crystal film in order to form SiO2; coating a passivation layer above a corrosive groove and around and above a piezoelectric island; applying a top electrode; adding a coupler used for connecting an adapter plate; selectively removing electrode material in order to leave out coupled resonators; manufacturing a gasket; peeling the silicon cover; manufacturing a cavity in SOI (otherwise using the SOI having the cavity); cutting; acquiring the adapter plate; manufacturing an epoxy resin dam structure; and connecting the resonators onto a substrate of the adapter plate (a flip-chip); encapsulation and separation.