Sanyo Electric Co., Ltd.

Tokyo University of Science

Hiroya Yamamoto

Masahiro Umewaka

Keiji Morijiri

Masaki Kinoshita

Takao Saeki

Jun Suzuki

Keitaro Sekine

Akira Hyogo

Takashi Iijima

Shinji Osugi

Keitarou Sekine

Akira Hyougo

To provide a receiver having a plurality of receiver circuits respectively connected to different antennas and a selecting circuit for selecting a receiver circuit whose receiving level is equal to a predetermined threshold value or a receiver circuit whose receiving level is higher than the predetermined threshold value as a main processing circuit to bring at least some of the receiver circuits other than the selected receiver circuit into a non-operation state.

Receiver

There is disclosed a tuning circuit having a coil and a capacitor comprises a resistance-adjustment circuit connected in parallel with the coil and the capacitor. The resistance-adjustment circuit changes a resistance of the tuning circuit when resonant. The resistance-adjustment circuit comprises a series circuit of a resistor and a switching element having an ON-resistance smaller than the resistance of the resistor, and turning on/off the switching element causes the resistance of the tuning circuit when resonant to change.

Tuning circuit with amplitude attenuation function and integrated circuit for radio communication apparatus

In some examples, a hysteresis comparator includes a series resistor portion including a plurality of resistors for dividing a power supply voltage, the series resistor portion generating a first midpoint voltage and a second midpoint voltage higher than the first midpoint voltage, a first comparator configured to compare the first midpoint voltage and a reference voltage, a second comparator configured to compare the second midpoint voltage and the reference voltage, and a flip-flop having a clock terminal to which an output signal of the first comparator is applied and a reset terminal to which an output signal of the second comparator is applied. In some examples, a hysteresis comparator further includes an OR gate to which output signals of the first comparator and the second comparator are applied, and an AND gate to which output signals of the first comparator and the second comparator are applied.

Hysteresis comparator and reset signal generator

A tuning circuit having an amplitude-varying function is disclosed that comprises a coil, a capacitor, and a resistance-adjusting element connected in parallel to the coil and the capacitor for varying resistance at time of resonance of the tuning circuit, wherein the amplitude of an output signal of the tuning circuit is varied by varying the resistance with the resistance-adjusting element.

Tuning circuit having amplitude-varying function

Transistors ( ) turn on and off with mutually opposite phase input signals. Capacitors ( ) discharge when the transistors ( ) turn on, and capacitors ( ) are charged by constant current from constant current sources ( ) when the transistors ( ) turn off. As a result, a gradually rising voltage is obtained at the positive input ends of comparators ( ) while the input signals are L. By comparing this with fixed voltages of reference sources ( ), signals having rise timing shifted from input signals by 90&deg; are obtained. The outputs of the comparators ( ) are mutually shifted by 180&deg;, and at the rise of these outputs, an RS flip-flop ( ) is set and reset so that signals delayed in phase by 90&deg; with respect to the input signals are obtained at its outputs.

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Ora-gun, Japan

Hiroya Yamamoto