Abstract: A frequency extractor extracts an input frequency of an input signal. The frequency extractor includes a frequency multiplier, first and second filters, a binary circuit and a frequency divider. The frequency multiplier obtains a signal of a multiplied frequency, the multiplied frequency being N times the input frequency, N being an integer greater than 1. The first filter, having a first bandwidth, filters the signal of the multiplied frequency to provide a first filtered signal. The binary circuit binarizes the first filtered signal to a binary signal. The frequency divider divides the binary signal by a factor of N to provide a divided signal. The second filter, having a second bandwidth, filters the divided signal to generate the input frequency in a form of a continuous wave, wherein the second bandwidth is about 1/N times the first bandwidth.

Abstract: A PLL (Phase-Locked Loop)-controlled oscillator has a temperature-compensated crystal oscillator having a quartz crystal unit, an oscillating circuit connected to the crystal unit, and a temperature compensating mechanism for generating a temperature compensating voltage for compensating for frequency vs. temperature characteristics of the crystal unit, and a voltage-controlled oscillator having an LC oscillating circuit, for being controlled by a PLL using the temperature-compensated crystal oscillator as a reference signal source. The temperature-compensated crystal oscillator has circuit components except for the crystal unit, the circuit components and the voltage-controlled oscillator being integrated in a one-chip IC. The one-chip IC and the crystal unit are integrally combined with each other in the PLL-controlled oscillator.

Abstract: A modulator for modulating carrier wave signals with an in-phase component signal and a quadrature component signal includes a fixed frequency signal generating means for generating two fixed-frequency signals differing 90 degrees in phase, a variable frequency signal generating means for generating a signal whose frequency can be varied according to a modulated signal to be produced, an in-phase component carrier wave signal generating means for mixing one fixed-frequency signal and the variable-frequency signal to generate a carrier wave signal for an in-phase component, a quadrature component carrier wave signal generating means for mixing the other fixed-frequency signal and the variable-frequency signal to generate a carrier wave signal for a quadrature component, an in-phase component modulating means for modulating the in-phase component carrier wave signal with the in-phase component signal, and a quadrature component modulating means for modulating the quadrature component carrier wave with the quadr

Abstract: A PLL (Phase-Locked Loop)-controlled oscillator has a temperature-compensated crystal oscillator having a quartz crystal unit, an oscillating circuit connected to the crystal unit, and a temperature compensating mechanism for generating a temperature compensating voltage for compensating for frequency vs. temperature characteristics of the crystal unit, and a voltage-controlled oscillator having an LC oscillating circuit, for being controlled by a PLL using the temperature-compensated crystal oscillator as a reference signal source. The temperature-compensated crystal oscillator has circuit components except for the crystal unit, the circuit components and the voltage-controlled oscillator being integrated in a one-chip IC. The one-chip IC and the crystal unit are integrally combined with each other in the PLL-controlled oscillator.

Abstract: A modulator for modulating carrier wave signals with an in-phase component signal and a quadrature component signal includes a fixed frequency signal generator for generating two fixed-frequency signals differing 90 degrees in phase, a variable frequency signal generator for generating a signal whose frequency can be varied according to a modulated signal, in-phase and quadrature component carrier wave signal generators for mixing respective ones of the fixed-frequency signals and the variable-frequency signal to generate carrier wave signals for in-phase and quadrature components, an in-phase component modulator for modulating the in-phase component carrier wave signal with the in-phase component signal, and a quadrature component modulator for modulating the quadrature component carrier wave with the quadrature component signal. Also, a demodulator is able to demodulate an in-phase component modulated signal and a quadrature component modulated signal from the modulator.

Abstract: A modulator for modulating carrier wave signals with an in-phase component signal and a quadrature component signal includes a fixed frequency signal generating means for generating two fixed-frequency signals differing 90 degrees in phase, a variable frequency signal generating means for generating a signal whose frequency can be varied according to a modulated signal to be produced, an in-phase component carrier wave signal generating means for mixing one fixed-frequency signal and the variable-frequency signal to generate a carrier wave signal for an in-phase component, a quadrature component carrier wave signal generating means for mixing the other fixed-frequency signal and the variable-frequency signal to generate a carrier wave signal for a quadrature component, an in-phase component modulating means for modulating the in-phase component carrier wave signal with the in-phase component signal, and a quadrature component modulating means for modulating the quadrature component carrier wave with the quadr

Abstract: To solve such a problem of a conventional direct conversion receiver that an image rejection ratio is insufficient owing to analog processing employed to reject an image, the present invention provides such a direct conversion receiver that the image can be rejected by digital signal processing to improve the image rejection ratio and also reduce the hardware load and the processing load. A HILBERT filter of a digital signal processing section shifts a quadrature component digital signal by 90° by HILBERT conversion to provide an output, while a delay circuit delays an in-phase component digital signal by the same delay time as a delay time by the HILBERT filter to provide an output, both of which outputs undergo addition or subtraction at an adder to have the image rejected there and then enter a complex frequency converter, where an offset provided at a local oscillator is removed by frequency conversion processing to output the in-phase component and quadrature component signals.

Abstract: An article management system generally includes an exit monitoring device, a storage shelf unit and a non-contact id tag. Each of these components are optionally equipped with a detection enhancing device for enhancing the transmission and or reception of signals between the non-contact id tag and the exit monitoring device or between the non-contact id tag and the storage shelf unit. The detection enhancing device includes a loop conductive line or an additional loop antenna.

Abstract: A frequency extractor extracts an input frequency of an input signal. The frequency extractor includes a frequency multiplier, first and second filters, a binary circuit and a frequency divider. The frequency multiplier obtains a signal of a multiplied frequency, the multiplied frequency being N times the input frequency, N being an integer greater than 1. The first filter, having a first bandwidth, filters the signal of the multiplied frequency to provide a first filtered signal. The binary circuit binarizes the first filtered signal to a binary signal. The frequency divider divides the binary signal by a factor of N to provide a divided signal. The second filter, having a second bandwidth, filters the divided signal to generate the input frequency in a form of a continuous wave, wherein the second bandwidth is about 1/N times the first bandwidth.

Abstract: A modulator for modulating carrier wave signals with an in-phase component signal and a quadrature component signal includes a fixed frequency signal generating means for generating two fixed-frequency signals differing 90 degrees in phase, a variable frequency signal generating means for generating a signal whose frequency can be varied according to a modulated signal to be produced, an in-phase component carrier wave signal generating means for mixing one fixed-frequency signal and the variable-frequency signal to generate a carrier wave signal for an in-phase component, a quadrature component carrier wave signal generating means for mixing the other fixed-frequency signal and the variable-frequency signal to generate a carrier wave signal for a quadrature component, an in-phase component modulating means for modulating the in-phase component carrier wave signal with the in-phase component signal, and a quadrature component modulating means for modulating the quadrature component carrier wave with the quadr