160 results about "Tuned radio frequency receiver" patented technology

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.