30 results about "Homodyne receiver" patented technology

A transceiver includes a transmitter and a homodyne receiver, wherein the receiver is used to process both antenna-received and antenna-reflected signals. Thus, during a receive mode, for example, the receiver downconverts antenna-received signals to baseband signals, which are then processed to recover receive signal information. Then, during a transmit mode for example, antenna-reflected transmit signals are fed back to the receiver, which is retuned to the desired transmit frequency, and thus downconverts the reflected transmit signals to baseband signals. These baseband signals are then processed to obtain a characterization of impedance mismatch between the transceiver's transmitter and the associated antenna. An adjustable matching network disposed in the transmit signal path thus may be adjusted based on the characterization to reduce the mismatch. Such configurations may be used with either single-band or multi-band embodiments of the transceiver, and the transceiver may be used in both TDMA and CDMA communication systems.

A low cost close range RFID Reader / Writer which is operatively connected to a control device which contains a transmitter and is configured to function as a homodyne receiver. The device can be constructed from low cost parts and can function in close ranges to other tags. The present invention provides increased RFID identification and isolation properties and is suitable for inclusion and operative use with a variety of applications.

The embodiments of the present invention provide a configurable homodyne / heterodyne RF receiver including first and second mixers. The configurable homodyne / heterodyne RF receiver functions as a homodyne receiver when the first and second mixers are configured to operate in parallel, and as a heterodyne receiver when the first and second mixers are configured to operate in series. The embodiments of the present invention further provides an RFID reader employing the configurable homodyne / heterodyne RF receiver to facilitate a listen-before-talk function.

Various embodiments of a coherent receiver including a widely tunable local oscillator laser are described herein. In some embodiments, the coherent receiver can be integrated with waveguides, optical splitters and detectors to form a monolithic optical hetero / homodyne receiver. In some embodiments, the coherent receiver can demodulate the full phase information in two polarizations of a received optical signal over a range of optical wavelengths.

The receiver comprises a first optical fibre input element (2) through which an information carrying element (S1) circulates, a local laser unit (3), an optical detection unit (4) and a differential demodulation unit (5). Characterised in that the information carrying signal (S1) of the input optical fibre (2) and the light beam (h1) generated by the local laser unit (3) are connected and detect in an optical detection block (4), which converts the information carrying signal (S1) into an electrical information carrying signal (S2) to be processed electrically in a demodulation unit (5) which performs a differential demodulation of the phase and quadrature components thereof, and subsequently combines same. The result in an optical receiver (1) with homodyne optical detection, the wavelengths of the input signal S1 and the synthonised light beam h1 coinciding, with high tolerance to the phase noise generated by optical communications lasers and not requiring use of an optical phase monitor (OPLL).

The embodiment of the invention discloses a receiver and an image suppression method thereof; after the receiver is electrified, a reference signal is input into a down link; the reference signal is processed by the down link and then is processed by an up link, and in-phase / quadrature (I / Q) data is obtained; the autocorrelation, the cross-correlation, the summing and averaging and an image correction coefficient of the obtained I / Q data are sequentially calculated, and the image correction coefficient is obtained; and the reference signal is finally cut off. Consequently, when in normal communication, after a radio frequency signal is processed by the up link, an image can be corrected according to the image correction coefficient. The method is particularly applicable to a homodyne receiver; the reference signal is preferred to be a white noise signal; and after primary image correction of an uplink homodyne modulator, the radio frequency signal carries out secondary image correction according to the image correction coefficient. Finally, the image can be corrected to -70dbm, and the error vector amplitude, in-band stray, sensitivity and other indicators of a system are improved.

Various embodiments of a coherent receiver including a widely tunable local oscillator laser are described herein. In some embodiments, the coherent receiver can be integrated with waveguides, optical splitters and detectors to form a monolithic optical hetero / homodyne receiver. In some embodiments, the coherent receiver can demodulate the full phase information in two polarizations of a received optical signal over a range of optical wavelengths.

A method and apparatus for maintaining sensitivity of a homodyne receiver over varying transmitter power levels is disclosed. The method includes adjusting output power levels of a transmitter driver. A bias supply voltage to the transmitter driver may be adjusted to adjust the output power levels. A control voltage to the transmitter driver may be adjusted to adjust the output power levels of the transmitter driver. A homodyne radio frequency tag reader may include the method.

A method and system for increasing the compression point of a receiver by deriving a feedback signal from mixer output signals. The feedback signal prevents the receiver from going into compression on strong out-of-band or blocking signals, while enhancing the receiver gain at the desired frequency. The desired frequency coincides with the local oscillator (LO) signal and is therefore particularly applicable for, but not limited to, homodyne receivers where selectivity can be made quite narrowband. Since the selectivity is coupled to the LO, a tunable receiver may be achieved that enables selectivity over a wide range of input frequencies.

In a synchronous circuit, a synchronizing signal generator combines either an optical BPSK signal or local oscillation light with a phase-shifted signal to produce different optical signals, one of which for use in producing a signal demodulated from the BPSK signal is square-law detected, and calculates the optical signal detected to convert the signal into an electric signal. The generator produces an electric phase-locking signal which will be a demodulated signal from the BPSK signal on the basis of the electric signal. The phase-locking signal is used as a modulating signal by an intensity-modulating circuit to modulate an incident continuous light into an optical intensity-modulated signal, which is optoelectrically converted and square-law detected by an optoelectric converter. The converted signal is used by an optical VCO circuit as a phase error signal to adjust the phase or frequency of the local oscillation light, which is supplied to the signal generator.

A method for reading and encoding RFID tags in a label printer configuration. A low cost close range RFID Reader which is operatively connected to a control device which contains a transmitter and is configured to function as a homodyne receiver. The device can be constructed from low cost parts and can function in close ranges to other tags. The method of the present invention provides the activation of reading and writing hardware to read and write information upon a tag and a label.

Various embodiments of a coherent receiver including a widely tunable local oscillator laser are described herein. In some embodiments, the coherent receiver can be integrated with waveguides, optical splitters and detectors to form a monolithic optical hetero / homodyne receiver. In some embodiments, the coherent receiver can demodulate the full phase information in two polarizations of a received optical signal over a range of optical wavelengths.

Demodulating an optical Differential Phase-Shift Keying (DPSK) signal is accomplished using a self-homodyne receiver for receiving the optical signal. A converter converts the optical signal received by the self-homodyne receiver into a representative electrical signal. A processor that processes the representative electrical signal using decision feedback multi-symbol detection in order to obtain a decision variable that indicates a differential phase-shift in the optical signal.

A receiver arrangement with AC coupling is specified in which a filter arrangement (3) is provided in a baseband signal processing chain in a homodyne receiver and can be switched between at least two high-pass filter cut-off frequencies. In this case, a brief changeover is made to a higher cut-off frequency when varying the gain of a low-noise baseband amplifier (2), for example when the received field strength changes, during the reception mode. The described arrangement allows changes to be carried out to the gain in baseband during the normal reception mode. The present receiver is accordingly suitable for code division multiple access methods, such as those which are provided in the UMTS Standard.

A method and system for increasing the compression point of a receiver by deriving a feedback signal from mixer output signals. The feedback signal prevents the receiver from going into compression on strong out-of-band or blocking signals, while enhancing the receiver gain at the desired frequency. The desired frequency coincides with the local oscillator (LO) signal and is therefore particularly applicable for, but not limited to, homodyne receivers where selectivity can be made quite narrowband. Since the selectivity is coupled to the LO, a tunable receiver may be achieved that enables selectivity over a wide range of input frequencies.

The invention discloses an indoor positioning method and device. An optimum frequency sequence is transmitted by a transmitting antenna so that a homodyne receiver can perform phase detection according to an obtained second harmonic signal and the received optimum frequency sequence to obtain a phase of the second harmonic signal. According to the phase of the second harmonic signal and a period integer of the optimum frequency sequence, differential distances of each pair of receiving antennas relative to a passive electronic tag are acquired respectively. Finally, a spatial position of the passive electronic tag is determined by a nonlinear conjugate gradient algorithm. By the above method, the influence of a multipath effect of the environment can be reduced, and high-precision positioning is achieved. The three-dimensional positioning error in the indoor environment is 10 cm on average.

A receiver including a fiber optic first input element, through which a signal carrying information circulates, a local laser block, a photo-detection block, and a block of differential demodulation is disclosed. The information-carrying signal of the optical fiber input and the beam of light generated by the local laser block provided in the receiver are coupled and detected in a block of optical detection, which converts the optical signal that carries information into an electrical signal that carries information, which is processed in a block of electrical demodulation, which performs a differential demodulation of its in-phase and quadrature components, combining them later. An optical receiver is obtained, featuring optical homodyne detection, being coincident the wavelengths of the input signal and the tuned beam of light, with a high tolerance to the phase noise, generated by the optical communications lasers, and with no need to use an optical phase-locked loop.

A method of correcting a signal transmitted via a communications channel having signal channels carrying base band components which are phase-shifted relative to each other, the method comprising the steps of receiving known samples (TS) of the base band components (500); estimating first parameters (α, β), for correction of second samples, based on the first samples compared with expected first samples; and receiving and correcting second samples of a base band component (I;Q). The method is characterized in further comprising the steps of: estimating second parameters (H) that describe the communications channel (103); and correcting the second samples of the base band component based on the first and second parameters. This finds its application especially in conjunction with direct conversion or homodyne receivers (102; 201) for mobile telecommunications.

A method and apparatus for maintaining sensitivity of a homodyne receiver over varying transmitter power levels is disclosed. The method includes adjusting output power levels of a transmitter driver. A bias supply voltage to the transmitter driver may be adjusted to adjust the output power levels. A control voltage to the transmitter driver may be adjusted to adjust the output power levels of the transmitter driver. A homodyne radio frequency tag reader may include the method.

Demodulating an optical Differential Phase-Shift Keying (DPSK) signal is accomplished using a self-homodyne receiver for receiving the optical signal. A converter converts the optical signal received by the self-homodyne receiver into a representative electrical signal. A processor that processes the representative electrical signal using decision feedback multi-symbol detection in order to obtain a decision variable that indicates a differential phase-shift in the optical signal.

A homodyne radar system includes a mixer that outputs a signal having a mixer output frequency that is a frequency difference between two input signals. When the frequency difference is small, low frequency noise may mask the actual signal. A variable phase shifter is added to one of the mixer inputs to change the phase at a predetermined rate of change. The phase shifter shifts the frequency of the input signal so that the mixer output frequency is offset by the predetermined rate. The low frequencies are mapped to frequencies that are above the noise frequencies. The phase shift may be achieved by adding a constant phase at predetermined time intervals. The sampling frequency for the resulting signal may need to be increased to accommodate the higher frequencies.

A system and method of reducing noise in an electronic shelf label system which shifts operation of the receiver away from noise frequencies. The system includes a controller for receiving signal levels and noise levels at different frequencies from a homodyne receiver, and for shifting operation of the receiver away from noise frequencies.

A receiver arrangement for receiving an optical signal comprising a number of optical channels equally distributed around an optical carrier frequency. The arrangement is configured to: i) received and detect the multichannel optical signal so as to provide at least one electrical quadrature signal comprising at least one folded channel, wherein each folded channel correspond to a set of two optical channels collapsed onto each other; ii) up-convert said at least one electrical quadrature signal so as to provide at least one up-converted quadrature signal comprising at least one pair of two separated unfolded channels, wherein each pair correspond to the two optical channels of a unique folded channel; and iii) demodulating said at least one up-converted quadrature signal so as to provide one baseband quadrature signal for each un folded channel such that each baseband quadrature signal corresponds to one unique optical channel.

A homodyne receiver according to the present invention includes a signal input and first and second mixers coupled to the signal input. A local oscillator provides a reference signal at the frequency of modulation of the input signal. The reference signal output by the local oscillator is passed through a switchable phase change element, the output of which is coupled directly to the first mixer and indirectly to the second mixer through a second phase change element. The switchable phase change element changes the phase of an input signal by a predetermined phase based on the state of a control input, such that the output of the phase change element in one state is pi radians out of phase with the output of the phase change element in the other state. The second phase change element changes the phase of an input signal by pi / 2 radians. The outputs of the mixers are coupled to a pair of switchable inverters and low pass filters. Switching of the switchable phase change element and the switchable inverters is controlled by a switching oscillator.

The embodiment of the invention discloses a receiver and an image suppression method thereof; after the receiver is electrified, a reference signal is input into a down link; the reference signal is processed by the down link and then is processed by an up link, and in-phase / quadrature (I / Q) data is obtained; the autocorrelation, the cross-correlation, the summing and averaging and an image correction coefficient of the obtained I / Q data are sequentially calculated, and the image correction coefficient is obtained; and the reference signal is finally cut off. Consequently, when in normal communication, after a radio frequency signal is processed by the up link, an image can be corrected according to the image correction coefficient. The method is particularly applicable to a homodyne receiver; the reference signal is preferred to be a white noise signal; and after primary image correction of an uplink homodyne modulator, the radio frequency signal carries out secondary image correction according to the image correction coefficient. Finally, the image can be corrected to -70dbm, and the error vector amplitude, in-band stray, sensitivity and other indicators of a system are improved.

This disclosure relates to an optical receiver arrangement (500) and a method for receiving a multichannel optical signal OB in an optical receiver arrangement (500), wherein the optical signal OB comprises a number of optical channels A, B, C, D equally distributed around an optical carrier frequency fLO and wherein the optical receiver arrangement (500) comprises an optical homodyne receiver (200) and a multichannel recovery unit (300). The method comprises the actions of: receiving and detecting the multichannel optical signal OB so as to provide at least one electrical quadrature signal IQV comprising at least one folded channel A+D, wherein each folded channel A+D correspond to a set of two optical channels A, D collapsed onto each other; and up converting said at least one electrical quadrature signal IQV so as to provide at least one up converted quadrature signal IQV-UP comprising at least one pair of two separated unfolded channels A, D, wherein each pair correspond to the two optical channels A, D of an unique folded channel A+D; and demodulating said at least one up converted quadrature signal IQV-UP so as to provide one baseband quadrature signal IQA, IQD for each un folded channel A, D such that each baseband quadrature signal IQA, IQD corresponds to one unique optical channel A, D.