JPS62135003A - Electronic tuning oscillator - Google Patents

Abstract

PURPOSE:To eliminate the need for the adjustment of a resonance frequency of an electronic tuning circuit by arranging and fixing the 1st and 2nd transmission lines while being tilted and changing a part overlapped onto the 2nd transmission line in moving the dielectric resonator corresponding to the moving quantity. CONSTITUTION:The 2nd transmission line 8 is arranged and fixed so that its prolonged line crosses with the prolonged line of the 1st transmission line 3. Let at optimum electric phase between the dielectric resonator 1 and a transistor 2 at the oscillation of, e.g., 6.5GHz in the electronic tuning oscillator be phi1, then the phase should be changed into a phase phi2 in changing the frequency into 6.2GHz. In moving the dielectric resonator 1 toward a termination resistor 4 along the 1st transmission line 3, since the overlapped part (shown in hatched lines in figure) between the dielectric resonator 1 and the transmission line 8 is increased gradually, the open end of the transmission line 8 is loaded with a capacitance because of the effect of a high dielectric constant of the dielectric resonator 1 to lower the resonance frequency of the electronic tuning circuit.

Description

[Detailed Description of the Invention] [Summary] In an electronically tuned oscillator, when changing the optimal electrical phase between the dielectric resonator and the negative resistance element in order to significantly change the oscillation frequency, the resonant frequency of the electronically tuned circuit is changed. is influenced by the dielectric constant of the dielectric resonator and changes in response to changes in the oscillation frequency, thereby eliminating the need for adjustment of the electronic tuning circuit.

[Industrial application field]

The present invention relates to improvements in electronically tuned oscillators.

Electronically tuned oscillators can change their oscillation frequency using an external control voltage, so they are used, for example, as modulators or voltage-controlled oscillators in the microwave band. However, it is desired that no adjustment of the electronic tuning circuit be required.

[Conventional technology]

FIG. 3 is a configuration diagram of a conventional example, and FIG. 4 is a diagram showing the relationship between the negative electronic impedance of the transistor and the load impedance. However, the bias circuit for the voltage variable capacitance element is omitted.

In FIG. 3, the first transmission line 3 magnetically coupled to the dielectric resonator 1 having the main resonance frequency fO has a negative resistance element ( (hereinafter abbreviated as a transistor) 2 is connected, and the other end is terminated with a resistor 4 having a resistance value approximately equal to the characteristic impedance of this transmission line.

At this time, the negative electronic impedance Zs of transistor 2
Assuming that the load impedance ZL is as shown in FIG. 4, when fO is 6.5 GHz, the sum of the reactance components of Zs and ZL becomes 0, so oscillation occurs at this frequency.

On the other hand, a second transmission line 5 which is magnetically coupled to the dielectric resonator and has a voltage variable capacitance element 6 connected to one end constitutes an electronic tuning circuit with this voltage variable capacitance element 6. The transmission lines are arranged parallel to each other through the dielectric resonator 1.
Fixed.

Now, when the noise voltage of the voltage variable capacitance element 6 is changed to change the capacitance value, the resonant frequency of the electronically tuned circuit changes, so the main resonant frequency fo changes, and the oscillation frequency of the electronically tuned oscillator changes. , for example, changes by about 0°lfo, and is outputted via the coupling antenna 7.

In addition, in order to obtain good linearity as an electronically tuned oscillator, the resonant frequency of the electronically tuned circuit is set to, for example, (0.7 to 0.8)f.
o.

[Problem that the invention seeks to solve]

Now, change the oscillation frequency from 5.5 GHz to 6.2 G, for example.
When lowering the frequency by about 5% to Hz, if the electrical phase remains at ψ1, the Z-100 point and Zs 6.2 as shown in Figure 4.
Since the point Gl (Z) is far away and the sum of the actances of ZL and Zs does not become 0, it does not oscillate at 6.2GH2.

Therefore, as shown in Figure 3, if φ1 is moved to φ2,
Correspondingly, Z in FIG. 4 moves to ZL', fo becomes fo', and at 6.2 GHz, the sum of the reactances of Zs and Z becomes 0, making it possible to oscillate at this frequency.

In addition, as mentioned above, the resonant frequency of the electronic tuning circuit and the main resonant frequency have a certain relationship, so in order to satisfy this relationship, it is necessary to lower the resonant frequency of the electronic tuning circuit.
The second transmission line must be made longer as shown in ".

That is, when it is desired to significantly change the oscillation frequency, there is a problem in that the resonant frequency of the electronic tuning circuit must be adjusted each time.

[Means for solving problems]

The above problem is that the extension line of the first transmission line 3 and the extension line of the second transmission line 8 intersect, and the dielectric resonator 1 is connected to the corrosion resistance element 2 along the first transmission line. When the second transmission line is moved away from the other side, the second transmission line is influenced by the dielectric resonator, and the electronic tuning circuit consisting of the second transmission line and the voltage variable capacitance element 6 is affected by the dielectric resonator. This problem is solved by the electronically tuned oscillator of the present invention, in which the first and second transmission lines are arranged so that the resonant frequency is lowered.

[Effect]

In the present invention, a correlation is established between a change in the installation position of the dielectric resonator, a change in the main resonant frequency fO, and a change in the resonant frequency of the electronic tuning circuit.

That is, when the oscillation frequency of the electronically tuned oscillator is changed significantly, the installation position of the dielectric resonator 1 must be changed, and in response to this change, the resonant frequency of the electronically tuned circuit is changed to the position of the dielectric resonator 1. Since the change is influenced by the dielectric constant of , there is no need to adjust the electronic tuning circuit even if the oscillation frequency is changed significantly.

〔Example〕

FIG. 1 shows a block diagram of an embodiment of the present invention. Note that the same reference numerals indicate the same objects throughout the figures.

In the figure, the extension line of the second transmission line 8 is arranged and fixed so as to intersect with the extension line of the first transmission line 3.

When this electronically tuned oscillator is caused to oscillate at, for example, 6.5 GHz, the optimum electrical phase between the dielectric resonator 1 and the transistor 2 (the phase in which the actance of Zs and ZL becomes 0 as described above) is φ1, then 6.5 GHz. When changing to .2GHz, it must be set to φ2 as described above.

Therefore, when the dielectric resonator 1 is moved along the first transmission line 3 toward the terminating resistor 4, the dielectric resonator 1 and the second
As the overlapped portion (hatched area in the figure) with the transmission line 8 gradually increases, the open end of the second transmission line 8 is loaded with capacitance due to the high dielectric constant of the dielectric resonator l. The resonant frequency of the electronic tuning circuit becomes low.

FIG. 2 shows a block diagram of another embodiment of the invention.

As shown in the figure, the first transmission line 9 has a sloped portion, and its operation is the same as that shown in FIG.

That is, the first and second transmission lines are arranged and fixed at an angle, and when the dielectric resonator is moved, the portion that overlaps with the second transmission line changes in accordance with the amount of movement. There is no need to adjust the resonant frequency of the electronic tuning circuit.

In this example, the dielectric resonator is cylindrical and the transistor is a field effect transistor, but the former is a dielectric resonator with a predetermined shape, and the latter is a semiconductor element that exhibits inherent resistance. Effects can be obtained.

〔Effect of the invention〕

As explained in detail above, there is an advantage that even if the oscillation frequency is changed significantly, there is no need to adjust the electronic tuning circuit.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a block diagram of another embodiment of the present invention, Fig. 3 is a block diagram of a conventional example, and Fig. 4 shows the negative impedance and load impedance of the transistor. A relationship diagram is shown. In the figure, 1 is a dielectric resonator, 2 is a negative resistance element, 3.9 is a first transmission line, 4 is a terminating resistor, 5.8 is a second transmission line, 6 is a voltage variable capacitance element,

Claims (1)

[Claims] A dielectric resonator (1) having a main resonance frequency; a first transmission line (3) magnetically coupled to the dielectric resonator and having a negative resistance element (2) connected to one end; ) and a second transmission line (8) having a predetermined length, which is magnetically coupled to the dielectric resonator, has one end open or short-circuited, and has a voltage variable capacitance element (6) connected to the other end. In the electronically tuned oscillator, the distance between the one end of the second transmission line and the second transmission line is shorter than the distance between the other end of the second transmission line and the first transmission line. and when the dielectric resonator is moved in a direction away from the negative resistance element along the first transmission line, electronic tuning consisting of the second transmission line and the voltage variable capacitance element An electronically tuned oscillator characterized in that the resonant frequency of the circuit is lowered.