Panasonic Corporation

Makoto Ohba

Kouji Takahashi

Yoshito Hirai

Until when a desired signal is received in a reception mode, a level comparator extracts a portion of a frequency-domain signal output from a Fourier transformer, the portion matching with the frequency of the desired signal, and, when the reception level of the extracted portion matching with the frequency of the desired signal is higher than a predetermined threshold value, determines that an interference signal exists. An LO frequency controller sets the frequency of a local signal (LO) based on the determination result in the level comparator such that the frequency of intermodulation distortion caused by the interference signal becomes an intermediate frequency of the frequency band of the desired signal. When it is determined that the interference signal exists, an RX controller changes gain settings of a low-noise amplifier circuit and gain settings of a variable gain amplifier circuit and changes the cutoff frequency of a filter circuit.

Radio communication apparatus and interference signal detection method

An input signal amplifier includes an inverting amplifier that outputs an input signal, a logic of which is inverted; a first switch. that switches an input, terminal of the inverting amplifier to be grounded or not; and a feedback resistor connected in parallel with the inverting amplifier and including a plurality of resistors with different values of resistance. The feedback resistor includes both a second switch that shorts or opens the feedback resistor via at least one of the resistors and a third switch that shorts or opens the feedback resistor via another of the resistors.

Input signal amplifier

A power supply voltage regulating apparatus includes: a reference voltage generating circuit that generates a reference voltage; an operational amplifier that amplifies the reference voltage and outputs the amplified reference voltage as a power supply voltage; a switching circuit that is connected between an output terminal of the operational amplifier and ground, and that performs a switching operation; a ring oscillator that is connected in parallel with the switching circuit between the output terminal of the operational amplifier and ground, and that generates an oscillation signal; and a controller that is connected with an input terminal of the reference voltage generating circuit, and that controls the reference voltage in accordance with an oscillating frequency of the oscillation signal, a temperature of the switching circuit, and an operating frequency of the switching circuit, to regulate the power supply voltage that is output from the operational amplifier.

Power supply voltage regulating apparatus, integrated circuit, and electronic apparatus

A correlated double sampling circuit has a sampling capacitor equally divided into a plurality of portions. In the correlated double sampling circuit, an input signal is sampled at a plurality of sampling points and an averaging switch is closed to obtain an average value of a plurality of sampling values obtained by sampling. High frequency noise superimposed on the input signal is thus reduced and a difference between the average values of the plurality of sampling values obtained by sampling is output.

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Osaka, Japan

Makoto Ohba