159 results about "Tuned radio frequency receiver" patented technology

A novel digitally controlled antenna tuning circuit that enables the implementation of low cost, wideband tuning circuits for antennas in receive applications. The invention is operative to switch a plurality of tuning elements into and out of a main receive signal path. Each individual tuning element is switched into or out of the receive signal path using a single PIN diode. For series connected tuning elements, the diode is connected in parallel to the tuning element. For tuning elements connected in parallel, the diode is connected in series with the tuning element. The diodes are switched in accordance with control voltages which forward bias the diodes to effectively create a low resistance path thus either inserting or removing a tuning element from the receive signal path depending on its configuration in the circuit.

A high performance radio frequency receiver includes a low noise amplifier with large binary and stepped gain control range, controlled impedance, and enhanced blocker immunity, for amplifying and converting a radio frequency signal to a current; a pulse generator for generating in-phase and quadrature pulses; a crossover correction circuit and pulse shaper for controlling a crossover threshold of the pulses and interaction between in-phase and quadrature mixers; and a double balanced mixer for combining the RF signal with the pulses to generate an intermediate frequency or baseband zero intermediate frequency current-mode signal. The in-phase and quadrature pulses have a duty cycle of 20-35%. The intermediate frequency signal and second order harmonics may be filtered with a high frequency low pass filter and a current injected complex direct-coupled filter. Decreased die size, current drain, cost, and complexity, as well as improvements in gain, 1/f noise, noise figure, sensitivity, and linearity may result.

The invention relates to a broadband radio frequency receiver and belongs to the technical field of wireless communication electronics. The broadband radio frequency receiver comprises a radio frequency front end module, an analog base band module and a digital baseband module; a zero-intermediate frequency receiver structure with orthogonal down conversion frequency is adopted; a radio frequency input signal sequentially passes through a low noise amplifier, a passive mixer, a trans-impedance amplifier, a low pass filter, a gain variable amplifier, an analog-digital converter, a decimation filter and a finite impulse response (FIR) filter; multiple radio frequency input signals within 50MHz to 6.3GHz can be processed by switching a low noise amplifier group and configuring local oscillation frequency, a sampling clock, filter bandwidth and the like; an external band-pass filter is not needed, so that the complexity of the system is reduced and the integration level is improved; a working frequency band is widened, and the flexibility and the reliability of the system are improved; in addition, the dynamic range is widened by double loop automatic grain control of a peak detection circuit and a power detection circuit. The broadband radio frequency receiver can be designed into an IP (Internet Protocol) core monolithic integration or can be in an external cascade.

A charging station for an electric vehicle, including payment processing over a communications network, is disclosed. The charging station includes a housing having an elongated shape emulating a parking bumper, including an elongated planar element disposed at an acute angle to a floor and designed to provide a barrier to wheels of the electric vehicle, an inductive charging element, a sensor for detecting a location of the electric vehicle in relation to the planar element of the charging station, a radio frequency receiver for receiving a signal including a unique identifier associated with the electric vehicle, a network interface controller configured for transmitting the unique identifier to a server and for receiving confirmation of payment for inductive charging provided to the electric vehicle and a processor configured for activating the inductive charging element to provide inductive charging to the electric vehicle responsive to receiving the confirmation of payment.

A two-way voice communication device which provides a high-level of acoustic noise reduction is disclosed. A resilient ear tip provides acoustic isolation and secures the earphone within the ear canal of the user. The ability to rotate the earphone within the ear canal allows the user to easily position an attached microphone. The audio signals may be conveyed by an included radio frequency receiver and radio frequency transmitter, or the earphone may be connected to an electrical audio device using a multi-conductor cable. Audio signals may be conveyed to one or both ears of a user. A switch to mute the audio signal from the microphone, or for supporting a push-to-talk mode of operation, may be included in the earphone housing, or on the cable.

A magnetic resonance multi-core array radio frequency device and a magnetic resonance signal receiving method are provided. The device comprises a radio frequency receiver which includes a radio frequency coil (11), a low noise preamplifier (13), a multiplexer (15), a radio frequency band-pass filter (17), a program control amplifier (19), a frequency synthesizer (21), a mixer (23), an analog to digital converter (29) and a controller (31). The controller (31) is used for controlling the multiplexer (15) to select a corresponding radio frequency coil channel, a corresponding filtering channel, gain of the radio frequency band-pass filter (17), and receiving a magnetic resonance digital signal transmitted by the analog to digital converter (29). Due to the multiplexer (15), there is no need to configure different circuits respectively for different nuclear magnetic resonance, redundancy of the circuits is reduced, and cost is reduced.

An image trap filter disposed between the low noise amplifier and the mixer of a radio frequency receiver that overcomes the adverse effect of process variations on image signal rejection for both a single-band radio frequency receiver and a multi-band radio frequency receiver by setting the image trap filter response at the center of the band of interest at production test. The image signal problem is presented at the input of the radio frequency receiver and the image trap filter is adjusted for the desired frequency response.

The present invention is a quadrature multi-mode RF receiver that uses a single quadrature mixer for tuning to desired frequency bands. In a direct conversion mode of operation, the RF receiver down converts a received RF signal directly into a baseband signal. In a VLIF mode of operation, the RF receiver down converts a received RF signal into a VLIF signal. When receiving a wanted RF signal, the frequency of the resulting VLIF signal is called the wanted VLIF frequency, and is based on the signal strength of the received RF signal. In one embodiment of the present invention, the wanted VLIF frequency is selected to be one of two VLIF frequencies. The wanted VLIF frequency is inversely related to the signal strength of the received RF signal.

The invention provides a dual-channel radio frequency receiver and a frequency planning method thereof. In the method, any two paths of radio frequency signals of a global navigation satellite systems with different modes or different frequencies are received through two independent signal receiving channels respectively; local oscillation frequency which is output to a frequency mixer by an voltage-controlled oscillator is regulated, so that radio frequency carrier frequency is mixed and an intermediate frequency signal is output; an intermediate frequency filter with image rejection is subjected to parameter configuration, so that an image rejection signal in the intermediate frequency signal matched with the intermediate frequency filter is rejected; and the frequency division value of a phase locked loop synthesizer with fractional-N frequency is configured so as to perform feedback control on the local oscillation frequency. By utilizing the method, sampling frequencies which are transmitted to two analog-digital converters by a digital phase locked loop are configured, and the sampling frequencies of the two analog-digital converters are same, so that the system and the interface design with an off-chip baseband processing chip of the system is simplified, and signal cross-talk is basically eliminated.

This invention claims a novel radio frequency receiver system for selecting a digitally modulated carrier frequency, and more specifically a Zero Point, amplitude Modulated (ZPM) carrier frequency. ZPM modulation does not create side-band frequencies, thus allowing individual carriers to be very closely spaced. Traditional methods of frequency selection utilize resonant tuning circuits in the antenna circuit and following amplifier circuits. Resonant tuning circuits are the assemblage of inductors and capacitors that are subject to parasitic oscillations, harmonic oscillations, as well as environmental effects. While modern technology has sufficiently overcome these detriments for traditional radio communication, ZPM theory desires to tune to a single frequency carrier with only one cycle of difference between carriers. Obvious to those skilled in the art, this requires a non-traditional method. For ZPM carriers, all signal-handling circuits must be non or insignificantly reactive and process the signal in linear fashion throughout the receiver signal path. This invention accomplishes the required functions by a unique combination of standard integrated circuits and circuit components.

Wireless communication is ubiquitous today with increasing deployments leading to increased interference, increasing conflicts, etc. Monitoring the wireless environment is therefore important for regulators, service providers, Government agencies, enterprises etc. Such monitoring should be flexible both in networks monitored within the wireless environment as well as detecting unauthorized transmitters, allowing dynamic network management, etc. However, such real time spectral/signal analysis in the prior art requires both a wideband direct conversion receiver (DCR), for high performance, wideband, fast, programmable spectral analysis, and a super heterodyne receiver for fast, narrowband, programmable demodulation for signal analysis. According to embodiments of the invention a single receiver design methodology exploiting a single RF circuit to provide superheterodyne and direct conversion receiver functionalities.

The invention relates to a low power radio frequency receiver which comprises: (a) an antenna for receiving a first radio frequency signal; (b) a radio frequency amplifier for amplifying the first radio frequency signal received by said antenna; (c) an oscillator for generating a second radio frequency signal having a predefined frequency and a predefined duty cycle to be mixed with said first radio frequency signal received by said antenna; (d) a mixer for mixing the first amplified radio frequency signal with second radio frequency signals and generating a third radio frequency signal; (e) an intermediate frequency filter for passing one or more intermediate frequencies of said third radio frequency signal and attenuating other frequencies of said third signal that are lower or higher than its cutoff frequencies, characterized in that it further comprises: (f) one or more switches for periodically and synchronously switching ON and OFF one or more of said radio frequency amplifier, said oscillator, and said mixer, said switches controlled by means of a control signal having a frequency that is higher than the frequency of data embedded within said first radio frequency signal; and (g) a control unit located within said radio frequency receiver for providing said control signal, wherein each of said switches is connected to a corresponding capacitor within said radio frequency amplifier, or oscillator, or mixer, said capacitor storing an operating point of said radio frequency amplifier, or oscillator, or mixer when said radio frequency amplifier, or oscillator, or mixer is switched OFF.

A garage door opener comprises at least two radio frequency transmitters, a radio frequency receiver, at least two memories, and a processor. Each memory corresponds to one radio frequency transmitter and stores a code of a corresponding radio frequency transmitter. The radio frequency transmitter is connected to the processor by electrical connectors. It is impossible to mis-study to the other radio frequency transmitter because the processor in the host computer has no program mode. Since each memory corresponds to one radio frequency transmitter, when one radio frequency transmitter is lost, a corresponding memory is eliminated to make the lost radio frequency transmitter disuse.

The invention discloses a front-end device for a digital radio frequency receiver, belonging to the technical field of microwave photons. The front-end device comprises a light source, an electrooptic polarization demodulator, a first polarization controller, a second polarization controller, a fiber beam splitter, a third polarization controller, a fourth polarization controller, a first polarization beam splitter, a second polarization beam splitter, a first balanced detector, a second balanced detector, a first analog/digital converter, a second analog/digital converter and a DSP (Digital Signal Processor). The invention also discloses a digital radio frequency receiver using the front-end device and a front-end receiving method thereof. The large dynamic front-end device for the digital radio frequency receiver, which has low cost and low environmental requirements, is realized.