Parasitic signal suppression circuit for an extremely high frequency oscillator
First Claim
1. A parasitic signal suppression circuit for an extremely high frequency (EHF) local oscillation device having an EHF oscillator, comprising:
- a first direct current cut-off device connected between an output of said EHF oscillator and an input of an amplifier;
a first low-pass filter coupled at one end thereof between said first direct current cut-off device and said amplifier and coupled to a direct current power source at the other end thereof for supplying said direct current power source to said amplifier;
a second direct current cut-off device connected between an output of said amplifier and an output of said EHF local oscillation device; and
a second low-pass filter coupled at one end thereof between said output of said amplifier and said second direct current cut-off device and coupled to a direct current supply source at the other end thereof for supplying said direct current supply source to said amplifier;
wherein said first and second direct current cut-off devices are composed of parallel resonators having a cut-off frequency matching an intermediate frequency band frequency of a device in which said EHF local oscillation device is provided;
said parasitic signal suppression circuit suppressing a parasitic signal at the output of said EHF oscillator from being transmitted to said output of the EHF local oscillation device and simultaneously passing a desired main signal to said output of said EHF local oscillation device.
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Accused Products
Abstract
An extremely high frequency parasitic signal suppression circuit for use in a local oscillator of an extremely high frequency radio or satellite communication system to eliminate parasitic signals included in a local oscillation signal. A first direct current cut-off device consisting of a microstrip line is connected between the output terminal of a phase-locked oscillator and the input of an amplifier, and to a first low pass filter to supply a direct current source for the amplifier. A second direct current cut-off device and second low pass filter are connected to the output terminal of the amplifier in the same manner as the input terminal.
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Citations
3 Claims
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1. A parasitic signal suppression circuit for an extremely high frequency (EHF) local oscillation device having an EHF oscillator, comprising:
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a first direct current cut-off device connected between an output of said EHF oscillator and an input of an amplifier; a first low-pass filter coupled at one end thereof between said first direct current cut-off device and said amplifier and coupled to a direct current power source at the other end thereof for supplying said direct current power source to said amplifier; a second direct current cut-off device connected between an output of said amplifier and an output of said EHF local oscillation device; and a second low-pass filter coupled at one end thereof between said output of said amplifier and said second direct current cut-off device and coupled to a direct current supply source at the other end thereof for supplying said direct current supply source to said amplifier; wherein said first and second direct current cut-off devices are composed of parallel resonators having a cut-off frequency matching an intermediate frequency band frequency of a device in which said EHF local oscillation device is provided; said parasitic signal suppression circuit suppressing a parasitic signal at the output of said EHF oscillator from being transmitted to said output of the EHF local oscillation device and simultaneously passing a desired main signal to said output of said EHF local oscillation device.
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2. A parasitic signal suppression circuit for an extremely high frequency (EHF) local oscillation device having an EHF oscillator, comprising:
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a first direct current cut-off device connected between an output of said EHF oscillator and an input of an amplifier; a first low-pass filter coupled at one end thereof between said first direct current cut-off device and said amplifier and coupled to a direct current power source at the other end thereof for supplying said direct current power source to said amplifier; a second direct current cut-off device connected between an output of said amplifier and an output of said EHF local oscillation device; and a second low-pass filter coupled at one end thereof between said output of said amplifier and said second direct current cut-off device and coupled to a direct current supply source at the other end thereof for supplying said direct current supply source to said amplifier; said parasitic signal suppression circuit suppressing a parasitic signal at the output of said EHF oscillator from being transmitted to said output of the EHF local oscillation device and simultaneously passing a desired main signal to said output of said EHF local oscillation device; wherein a pass band of said first and second low-pass filters matches a frequency band of said parasitic signal.
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3. A parasitic signal suppression circuit for an extremely high frequency (EHF) local oscillation device having an EHF oscillator, comprising:
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a first direct current cut-off device connected between an output of said EHF oscillator and an input of an amplifier; a first low-pass filter coupled at one end thereof between said first direct current cut-off device and said amplifier and coupled to a direct current power source at the other end thereof for supplying said direct current power source to said amplifier; a second direct current cut-off device connected between an output of said amplifier and an output of said EHF local oscillation device; and a second low-pass filter coupled at one end thereof between said output of said amplifier and said second direct current cut-off device and coupled to a direct current supply source at the other end thereof for supplying said direct current supply source to said amplifier; wherein said first and second direct current cut-off devices as well as said first and second low-pass filters are composed of microstrip lines, and said parasitic signal suppression circuit suppressing a parasitic signal at the output of said EHF oscillator from being transmitted to said output of the EHF local oscillation device and simultaneously passing a desired main signal to said output of said EHF local oscillation device.
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Specification