US Patent No. 9,263,989

DIFFERENTIAL OSCILLATOR


Patent No. 9,263,989
Issue Date February 16, 2016 
Title Differential Oscillator
Inventorship Takashi Nakaoka, Saitama (JP)
Hiroshi Hoshigami, Saitama (JP)
Assignee NIHON DEMPA KOGYO CO., LTD., Tokyo (JP)

Claim of US Patent No. 9,263,989

1. A differential oscillator, comprising:
a resonator that has at least a first resonance mode and a second resonance mode;
a differential amplifier circuit configured to oscillate the resonator;
a filter disposed in parallel to the resonator and the differential amplifier circuit, the filter having a first resonance
frequency in the first resonance mode and a second resonance frequency in the second resonance mode, a first impedance of
the filter at one of the first resonance frequency and the second resonance frequency is lower than a second impedance of
the filter at another one of the first resonance frequency and the second resonance frequency, wherein

the differential oscillator has a negative resistance at a frequency at which the second impedance of the filter is higher
while the differential oscillator does not have a negative resistance at a frequency at which the first impedance of the filter
is lower, among the first resonance frequency and the second resonance frequency.