US 6,724,274 B2Granted

Frequency-switching oscillator and electronic device using the same

AssigneeMurata Manufacturing Co., Ltd.

InventorsMasanori Fujidai, Toshio Hata

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Abstract

A frequency-switching oscillator which satisfies the conditions for oscillation, even when the switch width of the oscillation frequencies is great, without requiring a number of components to be increased. The impedance of a resonance system is set to satisfy the conditions for oscillation at two or more oscillation frequencies. A switching member is provided in the amplification system, and the oscillation frequencies are switched by changing the impedance of the amplification system. Since the resonance system does not require a switching member, loss is not caused by switching member in the resonance system, so the output level does not drop and the carrier-to-noise ratio does not deteriorate. Furthermore, without a switching member in the resonance system, the number of components can be reduced, making miniaturization and cost reduction possible.

Claims12

Dependent claims

A frequency-switching oscillator for switching between a plurality of oscillation frequencies, said frequency-switching oscillator comprising:

a resonance system;
an amplification system connected to said resonance system;
and
a switching member provided only within said amplification system, said switching member being controllable to set an impedance of said amplification system,
wherein said frequency-switching oscillator oscillates at a first oscillation frequency among said plurality of oscillation frequencies when said amplification system is set to a first impedance, and said frequency-switching oscillator oscillates at a second oscillation frequency among said plurality of oscillation frequencies when said amplification system is set to a second impedance,
wherein said switching member changes a value of feedback capacitance of said amplification system to alter frequency characteristics of a negative resistance of the impedance of said amplification system, and
wherein said resonance system has a resonant point between a phase of the impedance of said resonance system at said first oscillation frequency and a phase of the impedance of said resonance system at said second oscillation frequency.

4 more elements

An electronic device comprising a frequency-switching oscillator, wherein the frequency-switching oscillator comprises:

a resonance system;
an amplification system in communication with said resonance system;
and
a switching member provided only within said amplification system, said switching member being controllable to set an impedance of said amplification system,
wherein said frequency-switching oscillator oscillates at a first oscillation frequency among said plurality of oscillation frequencies when said amplification system is set to a first impedance, and said frequency-switching oscillator oscillates at a second oscillation frequency among said plurality of oscillation frequencies when said amplification system is set to a second impedance,
wherein said switching member changes a value of feedback capacitance of said amplification system to alter frequency characteristics of a negative resistance of the impedance of said amplification system, and
wherein said resonance system has a resonant point between a phase of the impedance of said resonance system at said first oscillation frequency and a phase of the impedance of said resonance system at said second oscillation frequency.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/093,630Filed 11 Mar 2002 · division
Priority: JP 11-30892829 Oct 1999
Published: US 2002/0093390 A118 Jul 2002
Granted: 20 Apr 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H03B 5/08
Generation of oscillations using amplifier with regenerative feedback from output to input: with frequency-determining element comprising lumped…
H03B 5/1203
Active element in amplifier being semiconductor device: the amplifier being a single transistor
H03B 5/1231
Active element in amplifier being semiconductor device: the amplifier comprising one or more bipolar transistors
H03B 5/1243
The means comprising a voltage dependent capacitance: the means comprising voltage variable capacitance diodes