160 results about "Tuned radio frequency receiver" patented technology

A long-range radio frequency (RF) transceiver-controller module configured to transmit and receive RF signals in one or more of the 433, 868, 915 MHz, and 2.4 and 5.8 GHz Industrial, Scientific and Medical (ISM) frequency bands is provided that is capable of consistently transmitting such signals over a range of 100 meters or more without line of sight, including underground. A wireless control system that comprises a plurality of the long-range RF transceiver-controller modules arranged in a distributed, ad hoc networking topography is also provided. The wireless control system has utility in a wide range of medical, industrial, agricultural, military and commercial applications, including, for example, the management of irrigation systems, manufacturing processes, security systems, sewage treatment and handling systems, hospital management systems.

A frequency conversion circuit of the present invention includes: (i) a first mixer for mixing the radio frequency signal having a frequency fRF with a first oscillation signal having a frequency fLO1 so that the radio frequency signal is downconverted into an intermediate frequency signal; and (ii) a second mixer for mixing the intermediate frequency signal sent from the first mixer with two local oscillation signals so that the intermediate frequency signal is downconverted into two base-band signals having different phases. The second local oscillation signals have phases of 0° and 270°, respectively. These frequencies satisfies: <?in-line-formulae description="In-line Formulae" end="lead"?>fLO1=kxfRF(k>1) <?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>fLO2=fLO1 / m, (m>1)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>k=m / (m-1).<?in-line-formulae description="In-line Formulae" end="tail"?> This arrangement ensures (i) a small frequency conversion circuit that can be mounted on an integrated circuit, (ii) a radio frequency receiver including the frequency conversion circuit, and (iii) a radio frequency transceiver including the radio frequency receiver.

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.

A frequency conversion circuit of the present invention includes: (i) a first mixer for mixing the radio frequency signal having a frequency fRF with a first oscillation signal having a frequency fLO1 so that the radio frequency signal is downconverted into an intermediate frequency signal; and (ii) a second mixer for mixing the intermediate frequency signal sent from the first mixer with two local oscillation signals so that the intermediate frequency signal is downconverted into two base-band signals having different phases. The second local oscillation signals have phases of 0° and 270°, respectively. These frequencies satisfies:fLO1=k×fRF(k>1) fLO2=fLO1 / m, (m>1)k=m / (m−1).This arrangement ensures (i) a small frequency conversion circuit that can be mounted on an integrated circuit, (ii) a radio frequency receiver including the frequency conversion circuit, and (iii) a radio frequency transceiver including the radio frequency receiver.

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.

An electronic implantable device with a power saving circuit incorporates a radio frequency receiver with high power consumption. The first power radio receiver of high power is normally turned off during a period of inactivity. When an analyzer forming part of a second radio receiver and coupled to the first radio receiver detects a predetermined identification code in a received radio frequency signal received by the second radio receiver, it outputs a signal to turn on the first power receiver.