280results about "Switched capacitor networks" patented technology

A switched capacitor notch filter for sampling an input signal using multiple sampling capacitors and multiple non-overlapping time periods. The charge from the sampling capacitors is averaged and transferred to the filter output during another non-overlapping time period.

A switched capacitor circuit includes an amplifier, a charging unit, an offset unit, and an integrating unit. The charging unit is coupled between an input node and a first node, and is for accumulating charge corresponding to an input signal during a sampling mode. The offset unit is coupled between the first node and an input of the amplifier, and is for maintaining the first node to be a virtual ground during an integrating mode. The integrating unit is coupled between the first node and an output of the amplifier, and is for receiving charge from the charging unit during the integrating mode.

An integrated receiver with channel selection and image rejection substantially implemented on a single CMOS integrated circuit is described. A receiver front end provides programmable attenuation and a programmable gain low noise amplifier. Frequency conversion circuitry advantageously uses LC filters integrated onto the substrate in conjunction with image reject mixers to provide sufficient image frequency rejection. Filter tuning and inductor Q compensation over temperature are performed on chip. The filters utilize multi track spiral inductors. The filters are tuned using local oscillators to tune a substitute filter, and frequency scaling during filter component values to those of the filter being tuned. In conjunction with filtering, frequency planning provides additional image rejection. The advantageous choice of local oscillator signal generation methods on chip is by PLL out of band local oscillation and by direct synthesis for in band local oscillator. The VCOs in the PLLs are centered using a control circuit to center the tuning capacitance range. A differential crystal oscillator is advantageously used as a frequency reference. Differential signal transmission is advantageously used throughout the receiver.

A band-pass filter made up by an operational amplifier and by an input circuit. The input circuit is formed by a capacitive filtering element, connected to the input of the operational amplifier; a coupling switch, coupled between an input node and the capacitive filtering element; a capacitive sampling element, coupled between the input of the filter and the input node; and a sampling switch, coupled between the input node and a reference-potential line. The coupling switch and the input sampling switch close in phase opposition according to a succession of undesired components sampling and sensing steps, so that the capacitive sampling element forms a sampler for sampling the undesired component in the undesired components sampling step, in the absence of the component of interest, and forms a subtractor of the undesired components from the input signal in the sensing step.

A switched capacitor notch filter for sampling an input signal using multiple sampling capacitors during multiple non-overlapping time periods. The charge from one set of sampling capacitors is averaged and transferred to the filter output during one non-overlapping time and the charge from another set of sampling capacitors is averaged and transferred to the filter output during a second non-overlapping time period.