JPS6079806A - Electronic tuning type fm modulator - Google Patents

Abstract

PURPOSE:To provide a FM modulation with good characteristic by providing a board including a microstrip type dipole to a position coupled electromagnetically to both a main resonator and a subresonator. CONSTITUTION:The microstrip type dipole MDP is mounted on the 3rd board SB3, which is placed between the 1st board SB1 and the 2nd board SB2. Thus, the SB3 is placed at the position coupled electromagnetically to both the main resonator MRS and the subresonator SRS and the degree of coupling between the resonators is adjusted by changing the position of the SB3 to the left and right along the SB2. Thus, the modulation sensitivity represented by a frequency variable amount to a DC impressed voltage to a varactor diode VRD is adjusted minutely by changing the position of the SB3. Since the position between the MRS and the SRS is adjusted minutely in this way, the FM modulation with good characteristic is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to an electronically tuned FM modulator using a main resonator and a sub-resonator that can provide FM modulation with good characteristics.

(2) Conventional technology and problems The amount of electrons j using a main resonator and a sub-resonator coupled to it
A conventional litl type FM modulator has a configuration shown in FIG. An oscillation section is provided on the first substrate SBI, and a Gunn diode GUND is connected to one end of the microstrip line MSL on which the main resonator MR3 (for example, a dielectric resonator) is mounted, and the output of the diode GUND is connected to the lines MS, L It is supplied to the outside through a window WD of the casing C3 provided at the other end. A varactor diode VRD and a resonance line RL are provided on the second substrate SB2 forming the sub-resonator SR3, and an operating bias DC connection line DCL is connected thereto. When the resonant frequency of the main resonator MR3 is fo and the resonant frequency of the sub-resonator SR8 is fl, when the output of the Gunn diode GUND oscillator is FM modulated, the linearity and phase characteristics of the modulation are as follows: adjustment of fl and two sides. The optimum state can be achieved by adjusting the degree of coupling between the resonators. At this time, in order to adjust the degree of coupling between both resonators, the distance between them has to be changed or the direction with respect to the sub-resonator has to be changed. Since the sub-resonator has the above-mentioned configuration, it is actually complicated to make it adjustable, takes time and effort to adjust, and has disadvantages in that it is not highly reliable.

(3) Purpose of the Invention The purpose of the present invention is to improve the above-mentioned drawbacks and to improve the characteristics of FM.
It is an object of the present invention to provide an electronically tuned FM modulator having a main resonator and a sub-resonator that can increase modulation by 1-1.

(B) Structure of the Invention The structure of the present invention to achieve the above-mentioned object is to provide an electronic circuit that uses a sub-resonator to change the frequency while taking out the oscillation frequency output determined by the main resonator through a microstrip line. In a tunable FM modulator, a microstrip dipole is electromagnetically coupled to both the main resonator and the sub-resonator at position ib°. 1 (The board was installed.

(5) Embodiment of the Invention FIG. 2 is a block diagram showing an embodiment of the invention corresponding to FIG. 1, and the same reference numerals as in FIG. 1 indicate the same parts. In FIG. 2, SB3 indicates the third substrate, on which the microstrip type dipole MDP is placed, and the first substrate SBI
and the second substrate SB2. Therefore, it is located at a position where it is electromagnetically coupled to both the main resonator and the sub-resonator, and by changing the position of SB3 to the left and right in FIG. 2 along the second substrate SB2, the degree of coupling between the resonators can be adjusted. . Therefore, the variable HIM sensitivity expressed by the amount of frequency variation with respect to the voltage applied to the varactor diode VRD can be finely adjusted by varying the position of the third substrate SB3. For example, fo is 26 G Ilz, modulation sensitivity is 0.5
~7Mllz/V. Note that the third substrate SB
3, it is best to fix it with adhesive when it can be adjusted to the predetermined position. 3 shows a top view of FIG. 2, and FIG. 4 shows an operational equivalent circuit diagram of FIG. 2.

Further, since the third substrate SB3 does not have a pattern on the back surface, it may be placed on the 5I12 "-" depending on the modulation sensitivity. FIG. 5 shows a top view in that case, and FIG. 6 shows a sectional view taken along line A--A in FIG.

(6) Effects of the Invention In this way, according to the present invention, the position between the main oscillator and the sub-resonator can be finely adjusted even with a simple configuration, so it is possible to quickly obtain a state with good characteristics for FM modulation. Moreover, it is easily obtained.

[Brief explanation of the drawing]

Fig. 1 (support) A diagram showing an example of the configuration of a conventional electronically tuned FM modulator; Fig. 2 1j a diagram showing the configuration of an embodiment of the present invention; 4 is an operational equivalent circuit diagram of FIG. 2, a diagram showing the configuration of another embodiment of the present invention, and FIG. 6 is a sectional view of FIG. 5. MR3 - lifetime resonator S RS, - sub-resonator SBI~S
B3 - Substrate MSL - Microstrip line GUND - Gunn diode V RD - Varactor diode MDP - Microstrip type dipole Patent applicant Fujitsu Co., Ltd. Agent Patent attorney Eisuke Suzuki Figure 5 A' Figure 6

Claims (1)

[Claims] In electronically tuned FM modulators, a sub-resonator is used to provide frequency modulation while the oscillation frequency output determined by the main resonator is extracted through a microstrip line.
An electronic 81M type FM modulator characterized in that a substrate including a microstrip type Goupole is disposed at a position electromagnetically coupled to both sub-resonators.