4850 results about "Frequency mixer" patented technology

A millimeter-wave transmitter-receiver uses an NRD guide as a fundamental configuration and includes a millimeter-wave signal oscillator, a pulse modulator, a circulator, an antenna and a mixer. In the millimeter-wave transmitter-receiver, a line length of a third dielectric guide is set so that δ=±π in which δ is a phase difference at a center frequency between a portion of a transmission millimeter-wave signal, which is reflected via a third dielectric guide on the leading end portion of the third dielectric guide and returned to leak to a third connecting portion of the circulator, and another portion of the millimeter-wave signal, which leaks from a first connecting portion to the third connecting portion of the circulator. It is possible to reduce the change in the mixer output and enhance the millimeter-wave transmission/reception performance.

The identification of low noise stimulation frequencies for detecting and localizing touch events on a touch sensor panel is disclosed. Each of a plurality of sense channels can be coupled to a separate sense line in a touch sensor panel and can have multiple mixers, each mixer using a demodulation frequency of a particular frequency, phase and delay. With no stimulation signal applied to any drive lines in the touch sensor panel, pairs of mixers can demodulate the sum of the output of all sense channels using the in-phase (I) and quadrature (Q) signals of a particular frequency. The demodulated outputs of each mixer pair can be used to calculate the magnitude of the noise at that particular frequency, wherein the lower the magnitude, the lower the noise at that frequency. Several low noise frequencies can be selected for use in a subsequent touch sensor panel scan function.

A harmonic suppression mixer for down converting an RF signal to a complex I and Q baseband signal that uses a plurality of switching mixers each with a gain stage to produce a sinusoidal weighted sum of the mixer outputs. Odd harmonics output by each switching mixer is suppressed in the composite signal. A low skew local oscillator (LO) clock generator creates multiple LO phases and drives the mixers. The mixer can be used in low noise direct conversion RF tuners. The mixer is configurable by programming gain stage coefficient values to achieve a variable number of effective mixers used in combination. At low tuning frequencies, all available mixers are programmed with unique coefficients and driven by different LO clock phases to achieve maximum harmonic suppression. At high tuning frequencies, some mixers are paralleled and duplicate coefficients are programmed or mixers are disabled to reduce the number of effective mixers.

A satellite digital audio radio receiver system and method. The inventive receiver includes a circuit for down-converting a first ensemble in a received combined signal in a first mode of operation and for down-converting a second ensemble from the received combined signal in a second mode of operation. The first ensemble includes a first signal received from a first transmitter, a second signal received from a second transmitter, and a third signal received from a third transmitter. The second ensemble includes a second signal from the first transmitter, a second signal from the second transmitter, and a second signal from the third transmitter. A controller is included to selectively switch the circuit from the first mode to the second mode. The first ensemble comprises first, second and third frequency slots and the second ensemble comprises fourth, fifth, and sixth frequency slots. In the illustrative embodiment, the first and second transmitters are mounted on first and second satellites and the third transmitter is a terrestrial repeater. Both ensembles are transmitted in accordance with the XM frequency plan. The first ensemble is down-converted using low side injection and the second ensemble down-converted using high side injection. The inventive circuit includes a synthesized frequency source. The circuit further includes a first intermediate frequency down-conversion stage with a first mixer for mixing the received combined signals with the output of synthesized frequency source. The circuit further includes first and second surface acoustic wave filters for separating the first and second signals received from the third signals. The inventive circuit further includes a second intermediate frequency down-conversion stage having second and third mixers for mixing the outputs of the first and second filters, respectively, with the output of a local oscillator.

A radio frequency (RF) demodulation circuit comprising a harmonic rejection mixing stage capable of receiving and mixing an incoming radio frequency (RF) signal having a frequency RF and a reference local oscillator (LO) signal having a frequency LO and generating an output signal in which out-of-band harmonic signals are suppressed. The harmonic rejection mixing stage comprises 1) a multiphase local oscillator (LO) generator for receiving the reference LO signal and generating M phase-shifted local oscillator signals having frequencies LO and 2) M mixers, each of the M mixers receiving the incoming radio frequency signal and one of the M phase-shifted local oscillator signals. Each of the M mixers generates a subcomponent signal. The subcomponent signals are then scaled and combined to produce the output signal.

A radar apparatus which can simply determine the sign of velocity of an object is provided. Laser light reflected by the object undergoes quadrature optical heterodyne detection performed by mixers, optical detectors, and a π/2 phase shifter, whereby I and Q component signals are output. A frequency analyzer performs FFT on a complex signal composed of the I component signal (real part) and the Q component signal (imaginary part) to thereby obtain its frequency spectrum. Since the frequency spectrum is calculated without being folded back even in a region where the frequency is negative, the sign of the Doppler frequency fd can be determined. When the Doppler frequency fd is positive, the sign of the velocity of the object is a direction toward the radar apparatus. When the Doppler frequency fd is negative, the sign of the velocity of the object is a direction away from the radar apparatus.

An audio spatial environment engine is provided for converting from an N channel audio system to an M channel audio system, such as in a dynamic down-mixer where N and M are integers and N is greater than M. The dynamic down-mix methodology consists of a static down-mix system utilizing an intelligent analysis and correction loop. The original N-channel audio signals are provided to a static down-mix process which produces a down-mixed M-channel audio signal. That M-channel audio signal is provided to an up-mix process which generates a subsequent N-channel audio signal. Any spectral, temporal, or spatial inaccuracies between the original N-channel audio and the subsequent up-mixed N-channel audio are then identified and corrected in the down-mixed M-channel audio signal over a plurality of frequency bands generating the final down-mixed M-channel audio signal. The corrections performed on the down-mixed M-channel audio signal consist of modifications to the relevant inter-channel spatial cues such as inter-channel level difference (ICLD) and inter-channel coherence (ICC) per frequency band.

There is provided by this invention an improved rf power control device for plasma applications for optimization of the feedback control voltage in the presence of harmonic and non-harmonic spurious frequencies. In this system, an oscillator and mixer, similar to those normally used in radio receiver applications are placed at the sampled output of the solid state rf signal source used for plasma ignition. The sampled output is mixed to a low frequency and filtered to remove the spurious frequencies that is created in the non-linear plasma. In this way, the feedback power control essentially ignores the spurious frequencies. In this application, the oscillator and mixer do not interfere with other desirable system characteristics and effectively isolate the feedback control voltage from changes in plasma spurious content. This allows rf power to be delivered to the plasma with greater accuracy than would otherwise be possible with conventional power control device and methods.

A quadrature amplitude demodulator demodulates a modulated signal on which quadrature amplitude modulation is performed. Oscillators generate an in-phase carrier signal having a rectangular wave, a trapezoidal wave or a waveform similar to these, and a quadrature carrier signal, the phase of which is shifted by ¼ cycle relative to the in-phase signal. First and second mixers respectively perform mixing of the modulated signal with the in-phase signal and the quadrature carrier signal. First and second integrators respectively integrate output signals of the first and the second mixers, for a predetermined period in accordance with the cycle of the in-phase carrier signal and the quadrature carrier signal. First and second A/D converters respectively convert outputs of the first and the second integrators into digital values.

A duty cycle correction (DCC) circuit including first and second clock dividers for dividing ordinary and sub-input clocks. Optional first and second variable delay devices delay the divided clocks. First and second mixers mix an optionally delayed ordinary divided clock and sub-ordinary divided clock, or an ordinary divided clock and an optionally delayed sub-ordinary divided clock. A logic combination device is included to produce a clock at the same frequency as the ordinary and sub-input clocks, with a corrected duty cycle.

A multi-channel synthesizer for generating at least three output channels using an input signal having at least one base channel, the base channel being derived from the original multi-channel signal, the input signal further including at least two different up-mixing parameters, and an up-mixer mode indication indicating, in a first state that a first up-mixing rule is to be performed, and, indicating, in a second state, that a different second up-mixing rule is to be performed, uses an up-mixer for up-mixing the at least one base channel using the at least two different up-mixing parameters based on the first or the second up-mixing rule in response to the up-mixer mode indication so that the at least three output channels are obtained.

A power amplifier system and method for locating carrier frequencies across a frequency band, identifying the modulation format of each carrier, and locating and suppressing undesired intermodulation distortion (IMD) products generated by the power amplifier. The system includes an amplifier for amplifying RF carrier signals in a main signal path, a variable phase shifter and variable attenuator on a feed forward path, and a tunable receiver that digitizes a portion of the frequency band to baseband. The tunable receiver includes a tunable voltage controlled oscillator which provides an oscillating frequency to a mixer and is phase-locked to a highly stable reference oscillator. The mixer downconverts a desired RF based on the oscillating frequency to IF. A filter passes only a selected portion of the IF signals, and the filter has a passband sufficient to discern both narrowband and wideband carriers and their associated IMD products. Based on the locations of the carrier frequencies, a processing unit determines the IMD locations of the carrier frequencies, determines the IMD locations, and adjusts the variable phase shifter and variable attenuator on the feed forward path until the IMD products in the main signal path are suppressed below a desired threshold.

Agile frequency converter and method, IF-RF level exchange process, and notch filtering techniques. System noise and spurious levels generated by channel frequency conversion is reduced in applications requiring broadband combining of frequency converters to form multichannel composite signal. Converter employs two-stage frequency conversion process, with gain exchange system using variable pre-mixer gain and variable post-mixer attenuation to maintain constant RF output signal power level. For those few conversion frequencies where distortion component(s) cannot be filtered without degrading desired signal, IF-RF level exchange is optimized for meeting the carrier-to-distortion (C/D) ratio specifications at slight expense of noise level for that channel only, while still meeting aggregate combined carrier-to-noise (C/N) specification requirements. Optimal apportionment of level exchange for each channel depends on specific frequency rejection capability of spurious components and is matched to filtering capability and stored within non-volatile memory of a microcontroller used in the frequency converter.

The transmitter of the transceiver includes: a transmitter-side mixers of a transmitter-side modulator; a transmitter-side voltage-controlled oscillator; and a transmitter-side divider. The divider having a dividing factor of a non-integral number is supplied with an oscillating output of the oscillator. A pair of non-quadrature local signals having a phase difference of 90° plus a predetermined offset angle is produced by the divider and supplied to the mixers. The transmitter includes a phase-shift unit which converts a pair of quadrature transmit signals having a phase difference of about 90° on an analog basis into a pair of non-quadrature shifted transmit signals. Consequently, quadrature modulation is performed by the mixers. Use of a similar configuration enables the reduction in interference of an RF signal with local signals supplied to receiver-side mixers of the receiver.

A method and system for processing radar data obtained from a platform which is subjected to non-uniform movement, the distance the platform travels during the formation of an image comprising an aperture; the system comprising software programming for performing a subroutine for building up an average pulse representing a single point on the aperture; the subroutine comprising the steps of inputting radar data from a radar antenna; passing the radar signal through low noise amplifier to reduce impact of electronic noise from the radar system; down converting the signal with a mixer to obtain a lower frequency; filtering out harmonics from the higher frequency range; sampling the radar data using an analog to digital converter at least at Nyquist down range frequency; based upon the IF of the radar; determining a scene center (center of SAR imagery) for the purpose of motion compensation; performing a two stage averaging scheme of the received signals with a variable window function; determining a window function based upon the velocity and acceleration of the platform and scene center; the window function comprising a first stage window; coherently averaging N pulses together to create an average pulse; performing an inverse Fourier transform; compensating to the scene center by multiplying by a complex exponential based upon both the GPS and inertial navigational system; summing the average pulses using low pass filter; the software programming operating to repeat the step of building up an average pulse a first predetermined number of times for a time period that is less than the Nyquist sample time interval; the software programming operating to repeat the step of building an average pulse for a predetermined number of times to generate a second predetermined number of average pulses; the software programming operating to perform a two dimensional inverse Fourier transform to obtain SAR image; outputting the SAR image on a display screen; and a display for displaying the outputted SAR image.

An optical mixer that, in one embodiment, has a single optical hybrid optically coupled to a single polarization beam splitter. The optical hybrid mixes a polarization-multiplexed optical communication signal and a local-oscillator signal to generate four mixed signals, each corresponding to a different relative phase shift between the communication and local-oscillator signals. The polarization beam splitter separates each of the mixed signals into two polarization components, subsequent processing of which enables an optical receiver employing the optical mixer to recover the data carried by the communication signal.

The semiconductor integrated communication circuit includes:

a low-noise amplifier; a receive mixer; a receive VCO; a demodulation-processing circuit; a modulation-processing circuit; a transmit mixer; a transmit VCO; a second-order-distortion-characteristic-calibration circuit; a quadrature-receive-signal-calibration circuit; and a test-signal generator. The test-signal generator generates first and second test signals using the transmit VCO. In the second-order-distortion-characteristic-calibration mode, the second-order-distortion-characteristic-calibration circuit variably changes an operation parameter of the receive mixer thereby to calibrate the second-order distortion characteristic to achieve its best condition while the first test signal is supplied to the receive mixer. In the quadrature-receive-signal-calibration mode, the quadrature-receive-signal-calibration circuit calibrates IQ mismatch of a quadrature receive signal to achieve the best condition thereof while the second test signal is supplied to the receive mixer. The integrated communication circuit can minimize the increase in chip footprint of a test-signal-generating circuit used to perform calibrations of both the second-order characteristic and IQ mismatch.

The invention discloses a vehicle-mounted millimeter-wave radar moving target recognizer. The vehicle-mounted millimeter-wave radar moving target recognizer is characterized in that the recognizer is a frequency synthesizer; a frequency agility continuous signal is modulated into a pulse signal and then is processed into a millimeter-wave signal by up-conversion; after being amplified by a power amplifier, the millimeter-wave signal is transmitted out; an antenna receives a radar echo signal back to a circulator and then the signal is transmitted into a frequency mixer; a high-frequency echo pulse and constant-amplitude high-frequency voltage generated by a high-stability local oscillator are mixed and the signal is reduced to a middle frequency and then is processed by a middle-frequency amplifier; the middle-frequency signal is directly sampled by an A/D (Analogue/Digital) conversion module; after being sampled, echo signals of a whole pulse string are stored into a storage unit; and information of targets, such as quantity, speed and direction, is measured by a signal processing unit and then is transmitted to an alarm executing unit. With the adoption of the structure, the vehicle-mounted millimeter-wave radar moving target recognizer has the advantages that 1 the distance measuring precision and the angle measuring precision of a moving target are improved; and 2 excessive hardware does not need to be added and the production cost is lower.

Disclosed is a wireless heart rate sensing system which comprises: an oscillator for generating signals of a specific frequency; a power divider for dividing power of the signals generated by the oscillator; a transmit antenna for radiating a first signal output by the power divider to a patient's chest; a receive antenna for receiving a signal, the frequency of which is transited by a motion of the patient's chest and which is reflected and returned; a mixer for combining frequency components of an RF signal received through the receive antenna and a second signal output by the power divider; and a baseband unit for filtering the signal combined by the mixer, converting it into a digital signal, and outputting the digital signal.