JPS639137Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a feedback oscillator, and more particularly to a high frequency feedback oscillator constructed using an amplifier and a cavity resonator or a dielectric resonator.

FIG. 1 shows a conventional feedback oscillator constructed using an amplifier 1 and a bandpass generator 2. As shown in FIG.
As shown in FIG. 1, in the conventional feedback type oscillator, a part of the output taken out from the output terminal of the amplifier 1 is fed back positively through the band wave generator 2, and oscillates at an oscillation frequency that satisfies the oscillation conditions. However, the first
In the feedback type oscillator shown in the figure, noise outside the oscillation band is generated and this appears at the output terminal.

In order to remove noise outside the oscillation band, the output of the amplifier is output through another bandpass filter, and the noise reflected from the other bandpass filter is placed between the amplifier and the other bandpass filter. It is necessary to provide a circulator with an attenuator for branching and absorbing noise outside the band, and since the additional bandpass filter and the circulator are provided, the circuit becomes large and the cost increases.

An object of the present invention is to provide a high frequency feedback oscillator capable of eliminating such noise outside the oscillation band using a simple and compact circuit.

According to the present invention, in the feedback oscillator, an input/output terminal of an amplifier and a cavity resonator or a dielectric resonator are electromagnetically coupled, and the output of the amplifier is fed back to the input of the amplifier via the resonator. A high frequency feedback oscillator is proposed, which is characterized in that a terminal for electromagnetic coupling with the resonator is provided separately from input/output terminals used for feedback, and an output is taken out from this terminal.

Embodiments of the feedback oscillator according to the present invention will be described in detail below with reference to the drawings.

FIG. 2 shows an embodiment of the feedback oscillator according to the present invention. In this example, the first
A semi-coaxial cavity resonator 3 is used in place of the band wave generator 2 in the figure, and all coupling is performed by electric fields. That is, the output of the amplifier 1 is positively fed back to the input side of the amplifier 1 via the antenna-coupled semi-coaxial resonator 3 to maintain oscillation. In this case, the oscillation output is taken out from the third terminal 3a which is electrically coupled to the semi-coaxial resonator 3. With such a configuration, it is equivalent to inserting a kind of band wave generator in the output circuit in the conventional circuit configuration as shown in FIG. 1, and the out-of-band noise generated in the oscillator is removed.

Furthermore, in the present invention, the load is not directly connected to the output of the amplifier, but is connected via a resonator that also acts as a branch, which has the effect of reducing changes in the feedback phase due to changes in load impedance.

FIG. 3 shows another embodiment of the feedback oscillator according to the present invention. In this embodiment, a dielectric resonator 4 is used, and the input side 1a and output side 1b of the amplifier 1 are electromagnetically coupled to the dielectric resonator 4, respectively, and the output side 1b of the amplifier 1 is connected to the dielectric resonator 4. Positive feedback is provided to the input side 1a of the oscilloscope via the oscillator, and oscillation occurs at an oscillation frequency that satisfies the oscillation conditions. At this time, the oscillation output is taken out from the coupling loop 4a which is electromagnetically coupled to the dielectric resonator 4. With such a configuration, the second
As in the figure, out-of-band noise generated in the oscillator is removed.

As explained in detail above, in the feedback oscillator according to the present invention, the input/output terminal of the amplifier and the cavity resonator or the dielectric resonator are electromagnetically coupled, and the output of the amplifier is transmitted through the resonator to the amplifier. A feedback oscillator whose input is fed back, is characterized in that a terminal is provided for electromagnetic coupling with the resonator in addition to the input/output terminal used for the feedback, and the output is taken out from this terminal. A simple and compact circuit that can eliminate noise outside the oscillation band without much cost, and can reduce changes in the feedback phase due to changes in load impedance, and is especially used in the microwave band. The effect is great when applied to feedback type oscillators.

[Brief explanation of the drawing]

FIG. 1 shows an example of a conventional feedback oscillator, and FIGS. 2 and 3 show embodiments of the feedback oscillator according to the present invention. In the figure, 3 is a cavity resonator, 3a is a third terminal, 4 is a dielectric resonator, and 4a is a third terminal (coupling loop).

Claims (1)

[Scope of utility model registration request] In a feedback type oscillator in which an input/output terminal of an amplifier and a cavity resonator or a dielectric resonator are electromagnetically coupled and the output of the amplifier is fed back to the input of the amplifier via the resonator, the input used for the feedback is A high-frequency feedback oscillator, characterized in that a terminal for electromagnetic coupling with the resonator is provided separately from the output terminal, and the output is taken out from this terminal.