30 results about "Homodyne receiver" patented technology

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 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.

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 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.

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.

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.

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 mixer of a homodyne RF receiver made from a CMOS process is provided. The mixer comprises a gain stage, a switch stage and a load stage. The gain stage receives a differential-typed RF signal and generating a first gained signal. The switch stage mixes the first gained signal and a LO signal to direct down-convert into a modulated signal. The load stage comprises a first transistor, an impedance element and a second transistor. The first transistor provides a low impedance to permit the modulated signal entering the load stage. The second transistor provides a high impedance to resist signals. The load stage converts the modulated signal to a second gained signal according to a first gain coefficient of the impedance element. The first transistor is a parallel pnp BJT, and the second transistor is a vertical npn bipolar BJT.

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.

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.

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.