Abstract: A mixed waveform configuration for wireless communications including a first portion that is modulated according to a single-carrier modulation scheme and a second portion that is modulated according to a multi-carrier modulation scheme. The waveform is specified so that a channel impulse response (CIR) estimate obtainable from the first portion is reusable for acquisition of the second portion. The first portion includes a preamble and header and the second portion typically incorporates the payload.

Abstract: A peak-to-average ratio (PAR) of a signal is reduced by clipping the signal at a threshold level and replacing desired frequency tones of the clipped signal with set of frequency tones of the signal. In one embodiment, the PAR of a signal is reduced by adding a peak cancellation signal to the received signal. The peak cancellation signal is generated by clipping the received signal at a threshold level and generating a difference signal by subtracting the received signal from the clipped signal. The peak cancellation signal thus generated is scaled by a scaling factor and added to the received signal to reduce the PAR of the received signal. The scaling factor is adjusted to maintain the desired quality of the received signal. In one embodiment, the PAR of an orthogonal frequency division multiplexed (OFDM) signal may be reduced.

Abstract: The invention relates to a method of estimating symbols carried by a digital signal that is received by a receiver over a communication channel (5), said symbols being multiplexed on orthogonal frequency sub-carriers. The inventive method comprises the following steps in relation to each symbol carried by the digital signal, consisting in: performing at least two transforms towards the frequency domain (8,9) on a portion of the received signal essentially corresponding to the symbol, said transforms being performed with a determined time lag (10) therebetween; estimating the parameters (r0, r1, . . . , rn, r?0, r?1, . . . , r?n) of the communication channel from pre-determined binary information contained in the digital signal; and estimating the symbol from a combination of the result of each of the transforms performed and the estimated communication channel parameters.

Abstract: A method and apparatus for providing channel feedback is provided herein. During operation a covariance matrix at time t (R) is calculated as a function of a received downlink signal. Matrix Ct is also calculated and is based on a previous quantized covariance matrix (Rqt?1), the covariance matrix (R) at time t, and a forgetting factor (?) that is applied to Rqt?1. The Ct is then used to create a DERC feedback message (signal or waveform) and may be transmitted with pilots on a proper feedback channel to a base unit. The base unit receives the feedback (Ct) as a DERC waveform on a proper feedback channel. The base unit uses non-coherent or coherent detection to detect the DERC values send by the remote unit and uses the DERC values with a previous quantized covariance matrix estimate, a forgetting factor, and a weighting value to compute a covariance matrix estimate to use for beamforming.

Abstract: An access point is disclosed herein that comprises a wireless network adapter configured to support a backhaul connection for a peer node to a network; a processing system configured to calculate precoding matrices that define spatial streams; and a transceiver configured to transmit data to the nodes on the spatial streams.

Abstract: A method for mapping data in a wireless communication system. The method includes generating a precoding matrix for multi-antenna transmission based on a precoding matrix indicator (PMI) feedback from at least one remote receiver where the PMI indicates a choice of precoding matrix derived from a matrix multiplication of two matrices from a first code book and a second codebook. The method further includes precoding one or more layers of a data stream with the precoding matrix and transmitting the preceded layers of data stream to the remove receiver.

Abstract: An apparatus and method for generating a codebook in a wireless communication system are disclosed. The codebook generation method includes determining one or more dominant singular vectors in a channel matrix for antennas and setting each of the dominant singular vectors as a random non-zero vector, generating a first codebook having codewords, a minimum distance between the codewords being maximized, using the random non-zero vector in a region that includes unit norm vectors each having a Euclidean distance to each of the dominant singular vectors, equal to or less than a predetermined value, generating a second codebook corresponding to a unitary matrix that rotates the random non-zero vector toward the dominant singular vectors, and generating a final codebook using the first and second codebooks.

Abstract: Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

Abstract: An apparatus and method for interference alignment and cancellation in a wireless communication system of a multi-user communication environment are provided. The apparatus includes a plurality of receivers, each receiver including a plurality of antennas for receiving signals from a plurality of transmitters. Each of the receivers detects signals of multiple users in a designed order and performs a specific interference alignment on the remaining signals. Also, each of the receivers transmits information about the detected user signal to other receivers to enable the other receivers to cancel the received user signal and perform a user signal detection and a specific interference alignment operation. Accordingly, it is possible to present various types of transmitter/receiver structures that can reduce the complexity while implementing the maximum capacity in an interference environment between a multi-user and single-user TX/RX pair.

Abstract: Transmissions are received on a plurality of uplink physical resource blocks. An acknowledgement or negative acknowledgement for each of the received transmissions is mapped to a downlink channel, such that linear increasing sequential indices of the physical resource blocks map to linear increasing sequential indices of n groups of the downlink channel which repeat until all the physical resource blocks are mapped, in which the downlink channel comprises a plurality of n groups.

Abstract: A feedback method for interference alignment in wireless network having K transmitters and K receivers, the method including: transmitting, by a transmitter n?1, a precoding vector of the transmitter n?1 (n being an integer between 2 and K?1) to a receiver n+1; calculating, by the receiver n+1, a precoding vector of a transmitter n using the precoding vector of the transmitter n?1; and transmitting, by the receiver n+1, the precoding vector of the transmitter n to the transmitter n.

Abstract: An apparatus includes an interleaver configured to interleave encoded data and to output a series of interleaved bits to be transmitted via a 1 MHz orthogonal frequency-division multiplexing (OFDM) transmission. The apparatus also includes a modulator configured to modulate the interleaved bits and a transform module configured to transform the modulated bits. A transmit module of the apparatus is configured to transmit the transformed bits included in one or more spatial streams of the 1 MHz OFDM transmission.

Abstract: A linearizer reduces nonlinear intermodulation distortion in radio frequency and microwave systems by first directly generating in-phase and quadrature nonlinear intermodulation products of the system input. Controllable amounts of each phase are then added back into the system such that the vector sum of nonlinear intermodulation products at the output is reduced or eliminated by destructive interference, while the fundamentals are substantially unaffected. The quadrature distorted signals are generated with two lightly-biased and thus overdriven differential pairs having gain-determining degeneration impedances that are in quadrature with each other. The amount of each quadrature phase summed to the output is controlled with electronically tunable four-quadrant variable attenuators. The quadrature phasing enables rapidly convergent tuning to minimize distortion using conventional scalar spectral analysis. The advantages of a linearizer using rectangular vector coordinate system are significant.

Abstract: An inband signaling modem receives digital user data for transmission to a remote location, via wireless and land line telecommunication networks. The modem converts the user data into audio tones for transmission, and encodes the audio tones into digital form suitable for transmission through a voice channel call session of a digital wireless network. After establishing a voice channel call session on a digital wireless network, the modem disables any echo cancellation or echo suppression means that may be encountered in the voice channel call session; and then transmits the user data audio tones. Preferably, disabling the echo cancellation or echo suppression means comprises transmitting a predetermined tone in the voice channel call session. Further, the modem preferably repeats the tone, to again disable echo cancellation or echo suppression means, at the beginning of each data burst during the call session.

Abstract: A method for adaptively driving data transmission and a communication device using the same are provided. The proposed method includes following procedures. Detection result is generated after detecting a receiving signal on a receiving path of the communication device. Driving parameter is generated according to the detection result. Finally, a transmitting signal on a transmitting path is adjusted according to the driving parameter.

Abstract: A method of communicating a chirp signal from a transmitter suitable for receipt at a proximal receiver and a distal receiver, the chirp signal including a plurality of packets, each packet including at least one symbol, each symbol including one or more identical chirps, the method including: generating the chirp signal by interleaving constituent packets of: (i) a first set of packets encoded with first data, each packet including one or more symbols having a first time period t1, and (ii) a second set of packets encoded with second data, each packet including one or more symbols having a second time period t2, where t1<t2; and transmitting the generated chirp signal.

Abstract: A distortion compensation circuit for compensating for the distortion characteristics of an amplifier, includes a distortion compensating coefficient calculating element and a distortion compensating operation element. The distortion compensating coefficient calculating element calculates a distortion compensating coefficient to be used for compensation of the distortion characteristics by comparing an input signal with the output signal amplified by the amplifier. The distortion compensating operation element performs a distortion compensating operation on the input signal, using a variably set bit format and the distortion compensating coefficient calculated by the distortion compensating coefficient calculating element.

Abstract: The present invention provides for a circuit with slicing wherein a gain asymmetry variation is decreased across the plurality of mixer slices. In one or more embodiments, a calibration unit can be provided to determine the characteristics of gain asymmetry variation; and a digital compensation unit can be provided to adjust the gain of the circuit over frequency.

Abstract: A method for providing a first modulation scheme based on a second modulation scheme, the second modulation scheme including a first constellation point associated with a first bit pattern and a second constellation point associated with a second bit pattern. The method includes mapping the second bit pattern from the second constellation point to the first constellation point, wherein an energy associated with the second constellation point is greater than an energy associated with the first constellation point.

Abstract: An apparatus comprises a direct digital synthesizer, a mixer having first and second input ports and an output port, and a numerically-controlled oscillator. The direct digital synthesizer has a first output coupled to the first input port of the mixer and a second output coupled to a control input of the numerically-controlled oscillator, and the numerically-controlled oscillator has an output coupled to the second input port of the mixer. The mixer provides a quadrature modulated signal at its output port, and the first and second outputs of the direct digital synthesizer control respective portions of the quadrature modulated signal. For example, the first and second outputs of the direct digital synthesizer may control respective amplitude and phase portions of the quadrature modulated signal.

Abstract: A digital broadcasting transmission/reception system having improved receiving performance and signal processing method thereof. A digital broadcasting transmitter according to the present invention includes a data pre-processor which processed robust data and generates robust data packet of predetermined format, a TS stream generator which combines robust data packet with a normal data packet to generate a TS stream of a predetermined format, a randomizer which randomizes the TS stream output from the TS stream generator, a convolution encoder which performs convolution encoding with respect to the robust data of the data output from the randomizer, and a RS encoder which performs RS encoding with respect to the data output from the convolution g encoder. Accordingly, digital broadcasting receiving performance can be improved in a poor multipath channel, while maintaining compatibility with existing transmission/reception system.

Abstract: A receiver includes a first local oscillator (LO), with a pair of in-phase and quadrature (IQ) mixers coupled to the first LO and configured to generate complex IQ signals having an IQ imbalance. The receiver also includes a second LO, with a complex mixer coupled to the second LO and configured to mix the complex IQ signals and generate intermediate frequency (IF) signals based thereon. A controller is coupled between the pair of IQ mixers and the complex mixer and configured to set the first LO and the second LO so that the complex IQ signals and an interfering signal generated due to the IQ imbalance of the complex IQ signals have a same sign and non-overlapping bands at an input of the complex mixer.

Abstract: A method for detecting a format of a frame in a communication system is presented. An embodiment of the method includes receiving the frame comprising a plurality of orthogonal frequency division multiplexing (OFDM) symbols. The plurality of OFDM symbols may include at least one signal field symbol. The method further includes determining a modulation associated with the at least one signal field symbol. The modulation may be a first modulation or a second modulation. Also, the method includes estimating a position of the at least one signal field symbol among the plurality of symbols, and extracting a coding rate of the received frame. The method then includes detecting the format of the received frame based on the determined modulation and the estimated position of the at least one signal field symbol, and the extracted coding rate of the received frame.

Abstract: An interpolation circuit includes: a generation circuit configured to generate interpolated data based on a plurality of pieces of input data in time sequence; a first analog digital converter configured to convert first interpolated data at a data point of the interpolated data into first digital data; and a second analog digital converter configured to convert second interpolated data at a change point into second digital data of the interpolated data, a second number of quantization bits of the second analog digital converter being smaller than a first number of quantization bits of the first analog digital converter.

Abstract: An apparatus to process an input signal received via a power line in a power line communication system includes a jammer remover and a jammer detector. The jammer remover removes interference resulting from transmission of electricity and the input signal over the power line from the input signal. The jammer remover generates a jammer-canceled signal using an adaptive filtering procedure. The jammer detector is coupled to the jammer remover to detect the interference.

Abstract: A method for carrier frequency tracking of a received signal having a burst structure includes dividing each burst into a number of segments. The carrier frequency offset of a first segment within a burst is measured to obtain a first segment carrier frequency offset measurement value. The carrier frequency offset of a second segment within the burst is corrected by a second segment carrier frequency offset correction value based on the first segment carrier frequency offset measurement value.

Abstract: Techniques are provided for detecting a coded signal in the presence of interference. In an embodiment, a primary transmitter corresponds to a desired transmitter, and one or more secondary transmitters correspond to interfering transmitters. Received symbols, which include interference and additive noise, are filtered to recover a set of original message bits. An estimate of the set of original message bits may be determined using an ordered successive interference cancellation (SIC) decoder that uses either a SIC detector or an AWGN-based detector, depending on the signal-to-interference ratio at a primary receiver.

Abstract: In a data carrier (1) which includes receiving means (5) for receiving a modulated carrier signal (MTS) which contains a data signal (DS1) encoded in conformity with an encoding method (MA, PW, MI, RTZ, FSK, PSK), demodulation means (9) for demodulating the received modulated carrier signal (MTS) and for outputting the encoded data signal (DS1) contained therein, decoding means (10, 20) for decoding the encoded data signal (DS1) and for outputting data (D1, D2), and data processing means (11) for processing the data (D1, D2) output by the decoding means (10, 20), the decoding means (10, 20) are provided with at least a first decoding stage (12) and a second decoding stage (13), the first decoding stage (12) being arranged to decode a data signal (DS1) encoded in conformity with a first method (RTZ) whereas the second decoding stage (13) is arranged to decode a data signal (DS1) encoded in conformity with a second method (MI).

Abstract: Disclosed is a method for receiving control information by a terminal in a wireless communication system. More specifically, the method comprises the steps of receiving setup information on component carriers which are allocated to a terminal from a base station, determining one of 1st decoding and 2nd decoding modes as a decoding mode for receiving the control information by using the setup information, and receiving control information corresponding to each component carrier according to the determined decoding mode.

Abstract: An apparatus, a method and a machine-readable storage medium to accommodate both high function and low cost wireless devices in a wireless network. An exemplary apparatus includes a receiver to wirelessly receive a first packet comprising first and second shifting pilot signals amidst first data symbols transmitted via multiple subcarriers in symbol sets; a transmitter to wireless transmit a second packet; and logic to track a phase shift using the first and second shifting pilot signals, to configure the receiver to compensate for the shift in phase, to refrain from using reception of the first and second shifting pilot signals to update an initial channel estimate derived from a preamble of the first packet, and to transmit third and fourth shifting pilot signals amidst second data symbols of the second packet.

Abstract: An embodiment of a decoder is disclosed. For this embodiment of the decoder, a first estimation unit and a second estimation unit are for iterative decoding. A scheduler is to receive a mode select signal to provide either an indication of first scheduling information or second scheduling information to the first estimation unit and the second estimation unit responsive to the mode select signal.

Abstract: A method of communication parameter detection for detecting a temporal length of a guard interval of cyclic messages in a communication is provided. The method includes: searching peaks of an autocorrelation signal in the communication signal, and providing a peak for each cyclic message; sorting a time difference between two consecutive peaks to one of bins of a histogram, and determining the temporal length of the guard interval according to a result of the histogram; while a peak is found, providing a signal average according to an average of the autocorrelation signal over an average calculating period, comparing whether a ratio of the peak to the signal average is greater than a threshold, and accordingly detecting whether the communication signal carries valid information.

Abstract: According to embodiments herein an ambiguity problem when compensating for frequency offset may be solved by compensating a received reference symbol according to two different frequency offset hypotheses; the estimated frequency offset and the a mirrored version of the same. Then by comparing the compensated reference symbol of the different frequency hypotheses with a target reference symbol, which is known at the receiver node 12, the frequency offset hypothesis which is most likely is used to compensate a received data symbol.

Abstract: A DAA (Detection And Avoidance) apparatus for use in a UWB receiver includes a frequency offset unit for adding a preset frequency offset to a UWB signal including a victim signal and an FFT unit for performing a fast-Fourier-transformation on the UWB signal with the frequency offset added thereto. The DAA apparatus further includes a DAA unit for detecting a victim signal from the fast-Fourier-transformed UWB signal and, when reception power of the victim signal is higher than a predetermined reference power level, changing a communication channel for the UWB signal to avoid interference.

Abstract: A receiver includes a plurality of receive antennas configured to receive radio signals from a plurality of transmit antennas, and a plurality of sets of RAKE fingers configured to generate first signals, wherein each set of RAKE fingers is coupled to a respective one of the plurality of receive antennas. The receiver further includes a weighting factor generator configured to generate weighting factors for weighting the first signals, wherein at least one of the weighting factors is generated by using first signals that are generated by at least two of the plurality of sets of RAKE fingers and received from at least two of the plurality of transmit antennas.

Abstract: One embodiment of the present invention relates to a combined mixer filter circuit. The circuit includes a sampler, a plurality of filter branches, and a coefficient generator. The sampler is configured to provide a sampled signal by sampling a received signal at a specified rate. The plurality of filter branches has selectable filter coefficients. The plurality of filter branches are configured to receive the sampled signal and generate a mixed and filtered output signal without a separate mixer component. The coefficient generator is coupled to the plurality of filter branches. The coefficient generator is configured to assign filter coefficient values to the selectable filter coefficients to yield a selected mixing function for the mixed filtered output signal.

Abstract: A method of adjusting the transmission time of a signal in a radio link, the method being performed by a transmitter configured to transmit the signal over the radio link to a receiver and comprising the steps of ascertaining an accuracy that the receiver assumes for the transmitter's clock, calculating an assumed drift of the transmitter's clock based on the assumed accuracy of that clock and the time since a previous correlation between the transmitter's clock and the receiver's clock; and transmitting the signal at a time dependent on the assumed drift.

Abstract: A system and a technique for recovering data from an input data stream without synchronization of an input sampling circuit to the input data stream determines a count of incoming samples (or frames) without generating a signal that is frequency-locked to the input data stream. A first clock is generated comprising a frequency that is greater than or equal to an expected frequency of the input data stream. A sample count is incremented in response to a sample received in the input data stream, and is decremented in response to a second clock signal. The second clock is generated the first clock signal by passing the first clock signal if the sample count of the sample counter does not equal a predetermined sample count value and by blocking the first clock signal if the sample count equals the predetermined sample count value.

Abstract: Mechanisms and techniques to evaluate data for a high speed I/O receiver logic. In an embodiment, a receiver circuit shifts a bit into a shift circuit in response to a rising edge of a data signal, where a count is started in response to the bit being subsequently shifted out of the shift circuit. Based on a value of the count, the receiver circuit generates a control signal for preparing physical layer receiver logic to transition to a burst mode of operation. In another embodiment, a receiver circuit includes a frequency divider to operate based on a data signal and a clock signal, wherein, based on operation of the frequency counter, a control signal is generated to indicate a line reset for physical layer receiver logic. The receiver circuit provides a feedback signal, based on the control signal, which is to limit activation of the frequency divider.

Abstract: An output signal adjustment system includes a signal adjustment unit, a reference slope generating unit, a slope detecting unit, a voltage-to-current conversion unit, and a control unit. The slope detecting unit compares the slope of the rising and falling edges of the output signal of the reference slope generating unit with that of the signal adjustment unit and outputs a voltage signal. The voltage-to-current conversion unit converts the voltage signal into a current signal. Based on the current signal, the control unit outputs a control signal for controlling the adjustment of the signal adjustment unit to the slope of the rising and falling edges of the output signal. The output signal adjustment system can automatically adjust the slope of the rising and falling edges of the output signal, so that the output signal is insensitive to the packaging, the printed circuit board, the transmission line and other sender loads.

Abstract: Embodiments of the present disclosure provide a transmitter, a receiver and methods of operating a transmitter and a receiver. In one embodiment, the transmitter has at least three transmit antennas and includes a feedback decoding portion configured to recover at least one group-based channel quality indicator provided by a feedback signal from a receiver, wherein each group-based channel quality indicator corresponds to one of a set of transmission layer groupings. The transmitter also includes a modulator portion configured to generate at least one symbol stream and a mapping portion configured to multiplex each symbol stream to at least one transmission layer grouping. The transmitter further includes a pre-coder portion configured to couple the transmission layers to the transmit antennas for a transmission. The receiver includes a decoder portion which is configured to use decoded signals from at least one group to decode the other groups.

Abstract: A storage rack for nuclear fuel assemblies, comprising a rigid structure defining a plurality of adjacent cells, and comprising in each cell a sleeve defining a cavity intended to receive a nuclear fuel assembly, the sleeve having, in cross-sectional orthogonal to the longitudinal direction, a generally polygonal shape whereof the sides are produced using plates made from a neutron-absorbing material. According to the invention, the sleeve also includes: profiles each forming a corner piece, arranged on at least several angles of the generally polygonal cross-section, these profiles serving as a mounting bracket for the plates made of a neutron-absorbing material; and a structure for maintaining the profiles therebetween.

Abstract: The present invention relates to an alternate feedwater injection system to at least partially mitigate the effects of an aircraft impact on a light water nuclear reactor positioned in a reactor building. The light water nuclear reactor has a primary system and a reactor core. The alternate feedwater injection system includes a water storage tank, an injection point into the primary system, a pump capable to transfer water from the water storage tank to the injection point and ultimately to the reactor core. The water storage tank and pump are located external to a reactor building and outside of an identified aircraft impact area or inside the identified aircraft impact area and provided with a means of protection from the aircraft impact.

Abstract: A power module includes a containment vessel completely submerged in a pool of liquid, and a support structure located at or above an approximate midpoint of the containment vessel, or center of gravity of the power module. The power module is supported by the support structure in combination with a buoyancy force of the pool of liquid acting on the containment vessel.

Abstract: A method and a system for catalytic recombination of hydrogen, which is carried in a gas flow, with oxygen, has the gas flow passed through a reaction zone with a number of catalytic converter elements, with steam being added to the gas flow before it enters the reaction zone. The method and system ensure a particularly high operational reliability of the recombination device, even in varying operating conditions or with varying operating methods, in particular with regard to a hydrogen feed, which is provided as required, in the steam/feed water circuit of the installation. For this purpose, the feed rate of the steam to be added is adjusted in dependence on a measured value which is characteristic of a current actual temperature in the reaction zone.

Abstract: A preventive maintenance/repair device 10 of the present invention includes: a device body 11, and holding mechanisms 13a and 13b connected to the device body 11, the holding mechanisms 13a and 13b being configured to hold the device body 11 on an outer circumferential surface of a cylindrical structure 19. Further, the device body 11 is equipped with a traveling and driving part configured to be circumferentially movable along the outer circumferential surface of the cylindrical structure 19. Furthermore, each of the holding mechanisms 13a and 13b is equipped with a maintenance/repair mechanism 16 configured to maintain and repair the cylindrical structure 19.

Abstract: Some embodiments include a counter having a first generator to generate signals having different frequencies, and a second generator to generate counter values of the counter. Each of the counter values may be based at least in part on a number of transitions of a respective signal among the signals. Other embodiments are described.

Abstract: An X-ray or infrared imagery apparatus that performs a large sweep while reducing the irradiation or illumination dose. It comprises a support, an X-ray or light ray source that emits a beam through a slit of a dose limiter which is driven in translation, a detector irradiated or illuminated by the beam in order to detect an intensity attenuated along the X-ray or light ray propagation path through the body, an analog-to-digital converter to convert the detected intensities into data in order to determine an attenuation of the X-rays or light rays by the body, and a programmed computer to process the data in order to obtain an image representing the attenuation of the X-rays or light rays. The dose limiter either is driven in translation at a speed proportional to the detector or driven in translation at the same speed than the detector in front of a reflector.

Abstract: An X-ray CT apparatus is provided. The X-ray CT apparatus includes an X-ray tube configured to apply an X-ray onto a subject, a scan device configured to rotate the X-ray tube about the subject to perform an X-ray CT scan, a first control device configured to switch an X-ray output of the X-ray tube from a first level to a second level smaller than the first level when the X-ray tube is placed at a first view angle, and configured to switch the X-ray output from the second level to the first level when the X-ray tube is placed at a second view angle, and a second control device configured to set the first view angle and the second view angle such that an X-ray exposure dose reduced by setting the X-ray output of the X-ray tube smaller than the first level becomes even on right and left sides.

Abstract: A system acquires images in the presence of a contrast agent of relatively long persistence using a synchronization processor, image acquisition device and imaging controller. The synchronization processor provides an image acquisition trigger signal for acquiring images at a particular point within both a cardiac and a respiratory cycle in response to signals representing cardiac and respiratory cycles. The image acquisition device includes an assembly comprising a radiation emitter and detector rotatable about a patient for acquiring images of a portion of patient anatomy at different angles. The imaging controller initiates acquisition of data representing multiple images in the presence of a contrast agent of relatively long persistence by repetitively, initiating rotation of the assembly to an angle, acquiring an image at the angle in response to the trigger signal and incrementally increasing the angle.