Abstract: A quadrature switching mixer is provided for mixing a received RF signal and a local oscillator signal, while rejecting an image signal associated with the RF signal. Input signal components in quadrature, that is, I and Q input components derived from the received RF signal, are respectively coupled through first and second input paths to corresponding commuting switches in a configuration of switches. Each of the switches operates to multiply respective quadrature components of RF and local oscillator signals to provide quadrature output signal components. A unidirectional device, such as a buffer amplifier included in a signal splitter, is placed in each input path to prevent any portion of an output signal component from leaking backward through one of the input paths to the other input path, and thus to the other output signal component.

Abstract: A quadrature switching mixer is provided for mixing a received RF signal and a local oscillator signal, while rejecting an image signal associated with the RF signal. Input signal components in quadrature, that is, I and Q input components derived from the received RF signal, are respectively coupled through first and second input paths to corresponding commuting switches in a configuration of switches. Each of the switches operates to multiply respective quadrature components of RF and local oscillator signals to provide quadrature output signal components. A unidirectional device, such as a buffer amplifier included in a signal splitter, is placed in each input path to prevent any portion of an output signal component from leaking backward through one of the input paths to the other input path, and thus to the other output signal component.

Abstract: An electronic communications device having a proximity sensor comprising: communication means (7) and a proximity sensor adapted to provide a control signal (Y2; Y3; Y4) indicative of whether an object (8) is in proximity of the device. The device is characterized by having a proximity sensor coil (L1; L2; L3; L5; L6; LP; LL) with an impedance, and oscillation means (C1, C2, 302; 601; 804) coupled to the proximity sensor coil (L1; L2; L3; L5; L6; LP; LL) to provide the control signal (Y2; Y3; Y4) in response to the impedance. In a preferred embodiment the proximity sensor coil is a loudspeaker coil. The invention also relates to a method of detecting proximity of an object relative to a loudspeaker (11; 703; 803) with a loudspeaker coil (L5; L6) which has an impedance.

Abstract: An electronic device (1), e.g. a mobile telephone having a front cover (6) and a capacitive proximity sensor, comprising: a first electrode (9; 27) and a second electrode (8; 21, 20), said first electrode having a large face (11, 12, 13; 29); and detector means connected to the first electrode (9, 27) and the second electrode (8, 21, 20) for detecting the capacitance of the first electrode relatively to the second electrode and for providing a control signal (Vprox) responsive to the capacitance. The large face (11, 12, 13; 29) of the first electrode is inclined relative to the front cover (6).

Abstract: A power-on reset circuit with glitch sensing capabilities is formed as part of the same integrated circuit chip containing other logical circuits. A port included in the integrated circuit chip enables a power-on reset signal generated by the integrated power-on reset circuit to be output from the chip and applied to other chips installed in a single chip or multi-chip electronic system. The power-on reset circuit compares a capacitor stored reset voltage to a reference voltage and outputs the power-on reset signal when the reset voltage falls below the reference voltage. Storage of the reset voltage by the capacitor is controlled by a glitch sensor which detects changes in voltage provided by a power supply in excess of a given threshold and, in response thereto, triggers a capacitor discharge. This causes the reset voltage to fall below the reference voltage, and the power-on reset signal to be output.

Abstract: An antenna switch for selectively connecting an output differential signal pair of an output power amplifier to a single-ended signal of an antenna when transmitting and selectively connecting an input differential signal pair of a low noise input amplifier to the single-ended signal of the antenna when receiving. A first balun having a single ended-signal connected to an antenna connects a first and second output differential signal to a power output amplifier. A second balun having a single-ended signal connected to the antenna connects a first and second input differential signal to a low noise input amplifier. A first diode selectively shorts the first output differential signal to the second output differential signal of the first balun when receiving and a second diode selectively shorts the first input differential signal to the second input differential signal of the second balun when transmitting.

Abstract: A monolithic high frequency voltage controlled oscillator trimming circuit includes a plurality of capacitance loops selectively connected between a first and second differential input of a voltage oscillator active network. A plurality of diodes, connected in series with the respective plurality of capacitance loops, selectively connect respective capacitance loops between the first and second differential input when forward biased. In a similar fashion, the plurality of diodes selectively disconnect the respective capacitance loops from the first and second differential input when reverse biased. A controller applies a forward biasing voltage to the diode of the selected capacitance loop to connect the capacitance loop to the active network of the voltage controlled oscillator and applies a reverse biasing voltage to the diode of the selected capacitance loop to disconnect the capacitance loop from the active network.