|| List of recent Phase Shift-related patents
| Radiation redirecting elements for portable communication device|
An antenna or set of antennae for a wireless device is provided by embedding the antennae into the battery case or generally the surface area of a wireless phone. The antenna connections are through the battery's connections to the wireless device.
| Method and system for a low-voltage integrated silicon high-speed modulator|
Methods and systems for a low-voltage integrated silicon high-speed modulator may include an optical modulator comprising first and second optical waveguides and two optical phase shifters, where each of the two optical phase shifters may comprise a p-n junction with a horizontal section and a vertical section and an optical signal is communicated to the first optical waveguide. A portion of the optical signal may then be coupled to the second optical waveguide.
| Beamforming with phase compensation|
A method and a base station for phase compensation in beamforming in a multi-antenna time division duplex (tdd) communication network. In a first transmission mode, the base station estimates a first phase shift between a first antenna port and a reference antenna port in uplink based on a measurement of a first sounding reference signal (srs).
| System and method for analyzing the energy consumption of electric loads in a consumer network|
The method for analyzing and displaying the energy consumption of electric loads according to the invention comprises, in principle, the following steps: providing at least one consumer network comprising a plurality of interconnected electric loads; sampling the total current, voltage and phase shift of the consumer network with a sampling rate of less than 5 hz; transmitting the sampled measured data through the internet to a means for load recognition; receiving the sampled measured data through the internet by the means for load recognition; determining individual loads in the measured data by the means for load recognition, comprising: determining temporal regularities of individual loads by means of a spectral analysis of the measured data, and/or generating load models for individual loads by modelling individual phenomena in the measured data by means of classifiers, and visualizing the energy consumption in the consumer network.. .
| Broadband butler matrix device|
A broadband butler matrix device includes a 90° branch-line hybrid coupler having an input terminal provided at one side thereof and configured to receive an input signal through the input terminal, and distribute and output the received signal such that the distributed signals have a phase difference of 90°. Further, the broadband butler matrix device includes a 45° broadband phase shifter configured to change the phases of the signals outputted through the 90° branch-line hybrid coupler, using an open and short stub having an electrical length of 45°..
| Power dividing phase shifter|
A power divider phase shifter is a structure of a hybrid ring formed of a power divider ring and two coupling rings. The input end of the power divider ring serves as the input of the power dividing phase shifter, while the output end of the power divider ring is connected with two parallel coupling rings, the output end of which each serves as the output of the power divider phase shifter..
| Modulating device and modulation method|
A modulating device including: a first convertor configured to generate a converted analog signal by analog conversion on a input digital signal, a modulator configured to generate a modulated signal by quadrature modulation, a phase shifter configured to generate a phase shift signal by phase rotation, a demodulator configured to generate a demodulated signal by quadrature demodulation, a second convertor to generate a converted digital signal by digital conversion, a calculating circuit configured to estimate a the first direct current offset based on the input digital signal and the converted digital signal, the first direct current offset being a noise of digital current component generated between the input digital signal inputted to the first convertor and the output signal inputted to the demodulator, and a correcting circuit configured to correct at least one among from the input digital signal to the output signal based on the first direct current offset.. .
| Electronic oscillation circuit|
An electronic oscillator circuit has a first oscillator, for supplying a first oscillation signal, a second oscillator, for supplying a second oscillation signal, a first controller for delivering the first control signal as a function of a phase difference between a first controller input and a second controller input of the first controller; a second controller for delivering the second control signal as a function of a phase difference between a first controller input of the second controller and a second controller input of the second controller; a resonator; at least a second resonance frequency, with a first phase shift dependent on the difference between the frequency of a second exciting signal and the second resonance frequency and processing means, for receiving the first oscillator signal and the second oscillator signal, determining their mutual proportion, looking up a frequency compensation factor in a prestored table and outputting a compensated oscillation signal.. .
| Method and magnetic resonance system for magnetic resonance thermometry|
In magnetic resonance (mr) thermometry, first and second magnetic resonance data that are acquired sequentially, from which a phase shift is determined between a measurement phase and a reference phase. In a first region of an examined person, the measurement phase is determined from the second magnetic resonance data and the reference phase is determined from the first magnetic resonance data.
| Gyro sensor driver and pulse translation device used therefor|
Disclosed herein are a gyro sensor driver and a pulse translation device used thereof. The gyro sensor driver, includes: a phase shifter that delays a signal output from an output terminal of a vibrating sensor to output a phase-shifted signal; a comparator that inverts a signal output from the phase shifter to output a clock signal; a reference voltage generator that generates and outputs reference voltage; and a pulse translator that receives the reference voltage output from the reference voltage generator and the clock signal output from the comparator to generate and output a signal of a predetermined pulse, thereby generating a desired driving signal with low current..
| Method for determining the acoustic characteristics of a mud filter cake|
A pressure response to low frequency harmonic pressure oscillations generated in a borehole by at least one oscillation source is registered by at least one acoustic sensor. A phase shift of stationary pressure oscillations registered by the acoustic sensor relatively to the low frequency harmonic pressure oscillations of the oscillation source and a ratio between an amplitude of the stationary pressure oscillations registered by the acoustic sensor and an amplitude of the low frequency harmonic pressure oscillations of the oscillation source are determined.
|Feed-forward linearization without phase shifters|
A method and system for providing a finite impulse response, fir, filter in a power amplification system are disclosed. An fir filter includes a first signal path having a first delay, τ1.
|Reduction of second order distortion in real time|
In a radio receiver, a method of reducing second order distortion components, involves at a first mixer, mixing an input signal with an oscillator signal to generate an i component of a received radio signal; at a second mixer, mixing the input signal with a phase shifted oscillator signal to generate a q component of the received radio signal; where the i and q components of the received signal have a receive bandwidth; computing an estimate of second order distortion components as a power output of the i and q components between approximately the receive bandwidth and twice the receive bandwidth of the received radio signals; and adjusting an operational parameter of the radio receiver to reduce the estimated value of second order distortion components. This abstract is not to be considered limiting..
|Estimation and reduction of second order distortion in real time|
A radio receiver method of reducing second order distortion components involves at a first mixer, mixing an input signal with an oscillator signal to generate an i component of a received radio communication signal; at a second mixer, mixing the input signal with a phase shifted oscillator signal to generate a q component of the received radio communication signal; computing an estimate of second order distortion as a function of the i and q components of the received radio communication signal; and adjusting an operational parameter of the radio receiver to reduce the estimated value of second order distortion components. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract..
|Extending beamforming capability of a coupled voltage controlled oscillator (vco) array during local oscillator (lo) signal generation through fine control of a tunable frequency of a tank circuit of a vco thereof|
A method includes implementing a coupled voltage controlled oscillator (vco) array with a number of vcos, and arranging a number of switched capacitor elements in a geometric proportion in a tank circuit of each vco to provide for finesse in control of a tunable frequency of the tank circuit. The method also includes utilizing a voltage control input of a varactor element of the tank circuit solely for achieving phase separation between the each vco and another vco of the coupled vco array based on the provision of finesse in the control of the tunable frequency of the tank circuit, and mixing local oscillator (lo) signals generated through the number of vcos of the coupled vco array with signals from antenna elements of an antenna array to introduce differential phase shifts in signal paths coupled to the antenna elements during performing beamforming with the antenna array..
|High frequency mixer, method and system|
A thin film circuit, particularly desirable for satellite communications, mixes rf and an lo giga-hertz-range input signals to yield an if signal by splitting the lo and rf signals into two, with a 180 degree phase shift introduced into one of the resulting signals. The lo and rf signals are then each mixed in parallel mixers.
|Method for improving cd micro-loading in photomask plasma etching|
Embodiments of the present invention provides methods to etching a mask layer, e.g., an absorber layer, disposed in a film stack for manufacturing a photomask in euv applications and phase shift and binary photomask applications. In one embodiment, a method of etching an absorber layer disposed on a photomask includes transferring a film stack into an etching chamber, the film stack having a chromium containing layer partially exposed through a patterned photoresist layer, providing an etching gas mixture including cl2, o2 and at least one hydrocarbon gas in to a processing chamber, wherein the cl2 and o2 is supplied at a cl2:o2 ratio greater than about 9, supplying a rf source power to form a plasma from the etching gas mixture, and etching the chromium containing layer through the patterned photoresist layer in the presence of the plasma..
|Aircraft predictive active noise cancellation|
An improved user experience is provided for passengers of a transportation vessel, such as an airplane. A passenger's experience is enhanced by allowing the passenger to enjoy media provided by an entertainment device without ambient noise.
|Phase interpolator with linear phase change|
Some embodiments relate to a phase interpolator. The phase interpolator includes a control block to provide a plurality of phase interpolation control signals which are collectively indicative of a phase difference between a first clock and a second clock.
|Circuit architecture for i/q mismatch mitigation in direct conversion receivers|
An electrical circuit includes a local oscillator configured to generate a first reference signal and a second reference signal having a predetermined phase shift with the first reference signal, an i-channel mixer configured to inject the first reference signal to an incoming signal and generate a first output, a compensation mixer configured to multiply the first output with a constant factor to generate a second output, a first low pass filter configured to approximately attenuate frequencies in the second output to generate a third output, and a first correcting filter configured to filter the third output to generate a fourth output. The first correcting filter is configured to reduce a channel impulse response mismatch between the first low pass filter and a second low pass filter, which is configured to attenuate frequencies in a q-channel of the incoming signal.
|Adaptive sampling filter process for scalable video coding|
A sampling filter process is provided for scalable video coding. The process provides for re-sampling using video data obtained from an encoder or decoder process of a base layer (bl) in a multi-layer system using adaptive phase shifting to improve quality.
|Distributed feedback (dfb) brillouin fiber lasers|
A brillouin fiber laser uses a distributed feedback (dfb) fiber bragg grating with a discrete π-phase shift, which is offset from the physical center of the grating as a resonator. Lasing is achieved by using the sbs gain in the dfb from narrow-linewidth laser pump radiation with an optical frequency that is higher than the central pass band of the grating by an amount nominally equal to the stokes's frequency shift, νb.
|Low-power and all-digital phase interpolator-based clock and data recovery architecture|
The proposed invention is about an improved method for serial-in and serial-out transceiver applications. The proposed system includes a dual loop phase locked loop (pll) architecture having a pll and a phase rotator (pr)-based delay locked loop (dll).
|Multiphase dc/dc converters|
A multiphase dc/dc power converter includes an input, an output, at least a first converter and a second converter coupled in parallel between the input and the output, an inductor coupled to the first and second converters, an output capacitor coupled between the first and second converters and the output, and a control circuit coupled to the first converter and the second converter. The first and second converters each include a power switch.
|Polarization converting dielectric plate|
A dielectric plate for use with a source of electromagnetic radiation of a predetermined frequency propagating along a propagation path is provided. The dielectric plate may include alternating elongate parallel first and second dielectric elements and a frame supporting the first and second dielectric elements distributed in a first plane.
|Indoor positioning with radio frequency chirp signal propagation delay measurement|
A radio frequency locator system and method. First, second and third reference devices are operable to transmit a plurality of spread spectrum chirp signals frequency offset from one another.
|Simple 2d phase-mode enabled beam-steering means|
System and apparatus embodiments are provided for beam-steering. In an embodiment, an apparatus includes a first hybrid splitter/combiner connected to a 0-th phase-mode feed of an array of antenna elements, a second hybrid splitter/combiner, a first pair of variable phase shifters connecting the first hybrid splitter/combiner to the second hybrid splitter/combiner, wherein the first pair of variable phase shifters control a steering direction of a main output beam radial with respect to an array axis by adjustments of respective phases of the variable phase shifters, and wherein the array axis is perpendicular to a plane of the array, and a third variable phase shifter connecting a 1-st phase-mode feed of an array of elements to an input of the first hybrid splitter/combiner, wherein the third variable phase shifter is configured to independently control a direction of the main output beam in a direction circumferential with respect to the array axis..
|Electronically steerable planar phase array antenna|
A two-dimensional (2-d) beam steerable phased array antenna is presented comprising a continuously electronically steerable material including a tunable material or a variable dielectric material, preferred a liquid crystal material. A compact antenna architecture including a patch antenna array, tunable phase shifters, a feed network and a bias network is proposed.
|Extending beamforming capability of a coupled voltage controlled oscillator (vco) array during local oscillator (lo) signal generation through accommodating differential coupling between vcos thereof|
A method includes implementing a coupled voltage controlled oscillator (vco) array with a number of vcos, and mixing local oscillator (lo) signals generated through the number of vcos of the coupled vco array with signals from antenna elements of an antenna array to introduce differential phase shifts in signal paths coupled to the antenna elements during performing beamforming with the antenna array. The method also includes accommodating differential coupling between the vcos to improve immunity to noise and/or interference during the beamforming compared to the vcos accommodating single-ended coupling therebetween..
|Phase shift based improved reference input frequency signal injection into a coupled voltage controlled oscillator (vco) array during local oscillator (lo) signal generation to reduce a phase-steering requirement during beamforming|
A method includes injecting a reference input signal into each voltage controlled oscillator (vco) of a number of vcos forming a coupled vco array to reduce a level of injection energy required therefor. The reference input signal is configured to control operating frequency of the coupled vco array.
|Extending beamforming capability of a coupled voltage controlled oscillator (vco) array during local oscillator (lo) signal generation through a circular configuration thereof|
A method includes separating phase of local oscillator (lo) signals generated by individual voltage controlled oscillators (vcos) of a coupled vco array through varying voltage levels of voltage control inputs thereto. The method also includes coupling the individual vcos of the coupled vco array to one another in a closed, circular configuration to increase phase difference between the phase separated lo signals generated by the individual vcos compared to a linear configuration of the coupled vco array.
|Extending beamforming capability of a coupled voltage controlled oscillator (vco) array during local oscillator (lo) signal generation through frequency multiplication|
A method includes separating phase of local oscillator (lo) signals generated by individual voltage controlled oscillators (vcos) of a coupled vco array through varying voltage levels of voltage control inputs thereto. The method also includes frequency multiplying an output of each individual vco of the coupled vco array to increase a range of phase differences between the phase separated lo signals generated by the individual vcos.
|Steerable transmit, steerable receive frequency modulated continuous wave radar transceiver|
Apparatus, method, and system example embodiments provide an improved integrated circuit rf front end to simultaneously transmit and receive signals for radar imaging. In an example embodiment, an apparatus comprises a transceiver coupled to a circularly polarized antenna assembly, capable of transmitting circularly polarized signals that are a component of a multi-signal radar beam; a power amplifier configured to amplify a transmit signal, coupled through isolation couplers to the circularly polarized antenna assembly; a phase shifting block circuit configured to perform phase shifting of a local oscillator signal, in response to the receipt of phase control signals, to perform phased-array beam steering of the multi-signal radar beam when the component circular signals are associated with signals transmitted from other transceivers receiving the phase control signals.
|System and method for calibration and built-in self test of automobile radar system|
An i/q mixer and processing method for a radar system include an rf input and an lo input. Phase shifters apply a selectable phase shift to the lo signal to produce a first phase-shifted version of the lo signal and a second phase-shifted version of the lo signal, the first and second phase-shifted versions of the lo signal being in quadrature.
|Inherently balanced phase shifting autotransformer|
A device and method of use for a phase shifting autotransformer is disclosed which has inherently balanced impedance characteristics. This is achieved by having the coil windings structured such that the following two requirements are met.
|Amplifier phase distortion correction based on amplitude distortion measurement|
This application discloses correction circuitry for correcting a phase distortion in an amplification circuit by measuring an amplitude distortion and controlling a phase shifting component based upon the measured amplitude distortion. In one embodiment, a first amplitude distortion sensor is coupled to a first node of an amplification circuit, and a first phase shifter is coupled to a second node of the amplification circuit.
|Logarithmic amplifier with universal demodulation capabilities|
A logarithmic amplifier (lda) is described that includes an amplifier configured to oscillate a modulated input signal, a feedback establishing a 180 degree phase shift between the amplifier input and the output and maintaining oscillation of the input signal, a parallel resonant circuit connected to the amplifier output causing the amplifier to resonate at or around a center frequency, and a controller connected to the amplifier input cyclically terminating oscillation of the input signal each time a pre-determined threshold of current is detected, the controller including a low pass filter configured to generate a second output signal having a repetition frequency. The lda may be used for am with or without a pll and/or a superhetrodyne.
|Frequency quadruplers at millimeter-wave frequencies|
Methods for increasing a signal frequency include generating two or more signals having a fundamental mode and one or more harmonics; phase shifting bifurcated components of the two or more signals in transmission lines; and combining the bifurcated components to create an output signal that cancels a fundamental mode, a second harmonic, and a third harmonic in the signals to produce a frequency-multiplied output signal.. .
|Method and apparatus for magnetic resonance imaging|
The method and system for correcting motion-induced phase errors in magnetic resonance imaging (mri) use a phase shift of the non-phase encoded reference echo-signal accumulated during the diffusion-weighting in order to characterize bulk motion and tissue deformation and to compensate their effect for correcting the diffusion/perfusion-weighted image. The sequences unbalanced with respect to the first motion derivative are used for distinguishing the perfusion component.
|Ion trap device|
An ion trap device is disclosed. The device includes a series of electrodes that define an ion flow path.
|Methods and systems for phase shifted pressure ventilation|
This disclosure describes systems and methods for providing pressure ventilation with a shifted pressure profile during ventilation of a patient. The disclosure describes a novel breath type that phase shifts the rise time of the delivered pressure profile to improve patient comfort and patient-ventilator synchrony..
|Magnetic flowmeter with automatic adjustment based on sensed complex impedance|
A magnetic flowmeter comprises a pipe section for process flow, a coil for generating a magnetic field across the pipe section, a current source for energizing the coil to generate the magnetic field at a coil drive frequency, and electrodes for sensing voltage induced across the process flow by the magnetic field. A processor calculates a function of the sensed voltage and generates a flow output based on the function.
|Parameter estimation in vamous receivers|
A desired signal and interfering signal are transmitted in the same timeslot and on the same frequency using an adaptive quadrature phase shift keying (aqpsk) modulated carrier. When the sub-channel power imbalance ratio (scpir) for the aqpsk modulated carrier is large and favors the interfering signal, the interfering signal is demodulated first to obtain demodulated soft bits.
|Waveguide with phase shifting portions|
An apparatus includes a plasmonic transducer with first and second oppositely disposed outer edges. A waveguide is configured to receive light from a light source, the waveguide have first and second portions that deliver first and second portions of the light to the first and second edges of the plasmonic transducer.
|Coherent dual parametric frequency comb for ultrafast chromatic dispersion measurement|
A wide-band optical frequency comb is provided to estimate an optical phase shift induced in a dispersive material. In contrast to the conventional techniques that rely on a single tunable laser for extracting the dispersion parameter at different frequencies, the wide-band optical frequency comb uses multiple comb lines for simultaneously evaluating the dispersion induced phase shifts in different frequencies.
|Inconspicuous tag for generating augmented reality experiences|
A system and method for generating virtual objects, the data for the virtual object is retrieved at least in part from a tag. The tag comprises a transparent physical surface and a visually imperceptible structure constructed in the transparent physical surface.
|Phase shift and attenuation circuits for use with multiple-path amplifiers|
Embodiments of circuits for use with an amplifier that includes multiple amplifier paths include a first series circuit and a second series circuit in parallel with the first series circuit. The first series circuit includes a first input coupled to a first power divider output, a first output coupled to a first amplifier path of the multiple amplifier paths, and a first adjustable phase shifter and a first adjustable attenuator series coupled between the first input and the first output.
|Power amplifier spurious cancellation|
This disclosure relates generally to power amplification devices and methods of operating the same. The power amplification devices are capable of reducing (and possibly cancelling) modulation of a ripple variation of a supply voltage level of a supply voltage onto a radio frequency (rf) signal.
|Phase-sensitive two-dimensional neutron shearing interferometer and hartmann sensor|
A neutron imaging system detects both the phase shift and absorption of neutrons passing through an object. The neutron imaging system is based on either of two different neutron wavefront sensor techniques: 2-d shearing interferometry and hartmann wavefront sensing.
|Diagnostic system for detection of fluid changes|
A diagnostic system for monitoring changes in a medium is disclosed. The system includes a transmitter configured to generate and transmit a time-varying magnetic field into a medium responsive to a first signal.
|Method for observing at least one object, such as a biological entity, and imaging system associated therewith|
The method further comprises, prior to the illumination step, addition of at least one marker in contact with the object(s), said or each marker being adapted to bind onto a corresponding object, the binding of said marker onto said object being adapted for increasing at least one characteristic quantity from among the absorption and the optical phase shift of said object.. .
Methods and apparatus for determining phase shift information between the first and second microphone signals for a sound signal, and determining an angle of incidence of the sound in relation to the first and second positions of the first and second microphones from the phase shift information of a band-limited test signal received by the first and second microphones for a frequency range of interest.. .
|Redundant operation of a backlight unit of a display device under open circuit or short circuit led string conditions and including dynamic phase shifting between led strings|
Disclosed embodiments relate to techniques for operating a backlight unit of a display device in a redundant mode and a non-redundant mode in the event of an open circuit condition or short string condition. For instance, in a redundant mode, multiple led strings are driven to provide a first quantity of light, such that the combined output from all led strings is capable of providing a total light output corresponding to a maximum brightness setting for the display device.
|High-precision ghz clock generation using spin states in diamond|
Techniques for obtaining a frequency standard using the crystal field splitting frequency of nitrogen vacancy center in diamond are disclosed. In certain exemplary embodiments, a microwave field is applied to the diamond and optically exciting the diamond under green light.
|Electro-optic silicon modulator with longitudinally nonuniform modulation|
A device, such as a silicon modulator, in accordance with the present disclosure employs pn diodes without sacrificing the modulation depth, while achieving lower loss and better impedance matching to 50-ohm drivers. In one embodiment, the device includes an input waveguide, an input optical splitter coupled to the input waveguide, first and second optical phase shifters coupled to the input optical splitter, an output optical splitter coupled to the first and second phase shifters, and an output waveguide coupled to the output optical splitter.
|Optical modulator with automatic bias correction|
An optical modulator uses an optoelectronic phase comparator configured to provide, in the form of an electrical signal, a measure of a phase difference between two optical waves. The phase comparator includes an optical directional coupler having two coupled channels respectively defining two optical inputs for receiving the two optical waves to be compared.
|Phased array antenna and associated methods|
A phased array transmitter is disclosed comprising a vector modulator, a true time delay block coupled to the vector modulator, a local oscillator phase shifter and rf-converter block coupled to the true time delay block, and an antenna. The vector modulator applies vector modulation to a baseband signal and provides an intermediate frequency signal to the true time delay block.
|Variable link sensorless brushless direct current motor controller for space and hardened applications|
A sensorless motor controller includes a variable link control, including a radiation-hardened field programmable gate array (fpga) and a back electromotive force (emf) decoder circuit. The back emf decoder infers the position of a rotor of the motor.
|Method and apparatus for reactive power capable inverters|
A system, method, and apparatus for converting dc input power to ac output power, including a dc-ac inverter employing: a first feedback loop for determining a maximum power point (mpp) and operating the dc-ac inverter proximate the mpp. A second feedback loop for determining a difference between a first power measurement and a second power measurement, producing an error signal indicative of the difference, and coupling the error signal to the first feedback loop to adjust at least one operating parameter of the dc-ac inverter to drive toward the mpp, where the first power measurement and the second power measurement are each determined based on a phase shift between an ac output voltage from the dc-ac inverter and an ac output current from the dc-ac inverter..
|Recovering data from quadrature phase shift keying modulated optical signals|
Systems, devices and techniques for processing received qpsk modulated optical signals include sampling the received signal at twice the baud rate, thereby producing samples that are then processed as 9-qam symbols using a decision directed least squares optimization method. Data bits are then recovered from the resulting symbol estimates.
|System and method for monitoring and control of an optical modulator for an m-qam transmitter|
A system includes an optical power meter operable to generate an optical power signal corresponding to the optical power of a received output signal generated by an optical iq-modulator. The system further includes a processor operable to receive the optical power signal and determine, based on a minimization algorithm and the received optical power signal, a first bias voltage to be applied to a first sub-modulator of the optical iq-modulator and a second bias voltage to be applied to a second sub-modulator of the optical iq-modulator.
|Optical modulator module and modulation method for optical signal|
An optical modulator module includes an optical modulator including an optical waveguide which conducts an inputted optical signal, and m modulator regions on the optical waveguide; and m discrete driving circuits serially connected to one another. The discrete driving circuits include a driving circuit which outputs a signal obtained from a digital input signal with a synchronization signal to one of the modulator regions, and a phase shifting circuit which outputs a signal resulting from giving a delay to a signal branched from the synchronization signal.
|Apparatus and method of differential iq frequency up-conversion|
A balanced transmitter up-converts i and q baseband signals directly from baseband-to-rf. The up-conversion process is sufficiently linear that no if processing is required, even in communications applications that have stringent requirements on spectral growth.
|Phase modulation apparatus|
A phase modulation apparatus has a light source outputting continuous light, two phase modulators, and an intensity modulator. The phase modulation apparatus is provided with an rz phase modulation circuit, in which the phase modulators phase-modulate the continuous light from the light source with data signals input to the phase modulators and generate two phase modulation optical signals, a phase shifter shifts the phase of one phase modulation optical signal by π/2, and an intensity modulator intensity-modulates a multiplexed signal, combined with the other phase modulation optical signal, with an input clock signal clk to convert the signal into an rz signal, and, thus, to output the rz signal, and a phase control circuit which adjusts the phases of the phase modulation optical signals generated by the phase modulator of the rz phase modulation circuit so that the output of the rz phase modulation circuit is maximum..