Abstract: An apparatus for extracting activity information and position information from a composite signal generated by a motion sensor includes an analog to digital converter for converting the composite signal from analog to digital format. A wide-band low pass filter having a frequency response of about zero hertz to about ten hertz and a narrow low pass filter having a frequency response of about zero hertz to about 0.5 hertz filter the digitized composite signal. An adder subtracts the output of the narrow-band low pass filter from the output of the wide-band low pass filter. The resulting difference represents information regarding the activity level of the motion sensor, and the output of the narrow-band low pass filter represents information regarding the position of the sensor.

Abstract: An apparatus for extracting activity information and position information from a composite signal generated by a motion sensor includes an analog to digital converter for converting the composite signal from analog to digital format. A wide-band low pass filter having a frequency response of about zero hertz to about ten hertz and a narrow low pass filter having a frequency response of about zero hertz to about 0.5 hertz filter the digitized composite signal. An adder subtracts the output of the narrow-band low pass filter from the output of the wide-band low pass filter. The resulting difference represents information regarding the activity level of the motion sensor, and the output of the narrow-band low pass filter represents information regarding the position of the sensor.

Abstract: An apparatus for converting capacitance in a capacitive sensor into a voltage signal. A capacitive sensor monitors a physical parameter. A capacitance of the sensor varies with the physical parameter. A voltage supply applies an alternating voltage to the capacitive sensor, which creates an output signal from the sensor. A modulator modulates the output signal, which produces a voltage signal that corresponds to the capacitance of the sensor.

Abstract: An integrated transconductor circuit in which the input transistor(s) passes a current across a reference resistor. This conventional arrangement produces current error terms of Vbe/R and Ib. According to the present invention, these terms are compensated by providing a compensation resistor which is matched to the first resistor, and a compensation transistor which is matched to the input transistor, interconnected to feed the appropriate current components to the output. For even better compensation, an additional transistor is optionally added to remove the effect of base current of the compensation transistor. In differential embodiments, the compensation resistor may be bridged or split. Zero, one, or more stages of current mirroring can optionally be used to provide the desired output.

Abstract: An integrated transconductor circuit in which the input transistor(s) passes a current across a reference resistor. This conventional arrangement produces current error terms of Vbe/R and Ib. According to the present invention, these terms are compensated by providing a compensation resistor which is matched to the first resistor, and a compensation transistor which is matched to the input transistor, interconnected to feed the appropriate current components to the output. For even better compensation, an additional transistor is optionally added to remove the effect of base current of the compensation transistor. In differential embodiments, the compensation resistor may be bridged or split. Zero, one, or more stages of current mirroring can optionally be used to provide the desired output.

Abstract: A current generator which includes a first bipolar transistor, the base of which is connected to a reference voltage and the emitter to ground through a first resistor. A first current mirror is connected to mirror the emitter current of this first transistor. The mirrored current is augmented by the base current of a second transistor (matched to the first transistor), and by current Vbe/R passed by a second resistor (matched to the first transistor), which is connected between the base and emitter of the second transistor. The current thus augmented drives a second current mirror. The output of the second mirror provides a precise reference current, determined by the reference voltage and the resistor magnitude.

Abstract: An integrated transconductor circuit in which the input transistor(s) passes a current across a reference resistor. This conventional arrangement produces current error terms of Vbe/R and Ib. According to the present invention, these terms are compensated by providing a compensation resistor which is matched to the first resistor, and a compensation transistor which is matched to the input transistor, interconnected to feed the appropriate current components to the output. For even better compensation, an additional transistor is optionally added to remove the effect of base current of the compensation transistor. In differential embodiments, the compensation resistor may be bridged or split. Zero, one, or more stages of current mirroring can optionally be used to provide the desired output.

Abstract: A transconductance amplifier comprises two complementary differential amplifiers at the input (T1a,T2a; T1b,T2b), the quiescent currents of which are fixed by two current sources (Ia, Ib), respectively. The transconductance amplifier has a first operating range where the two differential amplifiers are active and second and third operating ranges where only one differential amplifier is active. Means (T3a,T4a,Iaa; T3b,T4b,Ibb) are provided for deriving a predetermined fraction of the currents provided by the current sources to the differential amplifiers, the means being respectively in one of the second or third ranges and the predetermined fraction being such that the transconductance of the active transistors in one of the second or third ranges is equal to twice the transconductance of the transistors in the first range.

Abstract: A current mirror that comprises a first branch which includes the series arrangement of a diode (D.sub.1) and the main current path of a transistor (T.sub.1), and a second branch comprising the series arrangement of the main current path of a transistor (T.sub.2) and a diode (D.sub.2). In order to increase the voltage Vs available at the current mirror output, a diode (D.sub.3) is connected in the first branch and a transistor (T.sub.3) is connected in the second branch. One electrode of the diode (D.sub.3) is connected to the base of a transistor (T.sub.4), whose collector receives a supply voltage (U) and whose emitter is connected to the base of the transistor (T.sub.2). The base of the transistor (T.sub.1) is connected to one electrode of the diode (D.sub.2) and to the emitter of the transistor (T.sub.2). A diode (D.sub.4) is poled in the forward direction between the power-supply source U and the base of the transistor (T.sub.3).