JPS6033010B2 - High frequency transmitters especially for radiosondes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a high-frequency transmitter, in particular for radiosondes, which is provided with a transistor oscillator stabilized with a coaxial resonator.

The object of the invention is to make the structure of the transmitter as simple as possible and to manufacture it cheaply, for example in the frequency range 400-1.
The object of the present invention is to provide a high frequency transmitter of 600 MH2, especially for a radiosonde.

Another objective is to ensure the starting of the transmitter's oscillator in all conditions, to be able to tune it easily and easily and to eliminate the effects of changes in the characteristics of the various components, e.g. transistors, and to increase its output frequency. The object of the present invention is to provide a high frequency transmitter of the above type which is adjusted to be stable. Another object of the invention is to provide a transmitter of the above type which is simple in construction and yet sufficiently robust from the point of view of the conditions of use. In order to achieve the objects mentioned above and which will be explained later, the main features of the invention are that the oscillator components are mounted on an end wall portion which is rotatably mounted to the end of the outer tube of the coaxial resonator. Furthermore, the tightness with which the high frequency is coupled to the coaxial resonator is adjusted by the rotational movement of the end wall portion. Embodiments of the invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: FIG.

The high frequency transmitter shown is for a meteorological radiosonde and has a transistor oscillator stabilized in the frequency range of 4000 MHz and equipped with a coaxial resonator 10.

The basic circuit of the transmitter can be classified as a Crappie oscillator, which is a variation of the Colpitt oscillator, as is well known. The main circuit of the oscillator is shown in Figure 1. In order to create and maintain oscillation, the inherent parasitic reactance of transistor TR, and the components C,,C2,C3,C4,L,,L2
A stray bond between is used.

Variable capacitor C. shown in FIG. mainly affects the vibration frequency.

Physically, the variable capacitor C is a setting screw 14,
This screw 14 is provided centrally in the end wall section 20 of the outer tube 11 of the coaxial resonator 10, i.e. the coaxial resonator 10
The degree of penetration of the coaxial resonator 10 into the tubular center conductor 12 can be adjusted. The tightness of the coupling between the transistor TR, and the resonator 10 (C5, shown in dotted lines) eliminates the influence of changes in the characteristics of the transistor TR, in particular, and also ensures the starting of the oscillator, which also reduces the frequency of the transmitter. and output are made adjustable according to the invention to stabilize the output.

Regarding the mechanical structure of the transmitter according to the invention, the transmitter has an empty cavity 10, which consists of a cylindrical outer tube 11 and a tubular inner tube 12.

A coaxial resonator 1 has a terminal 13, and this terminal 13
The output of the transmitter may be coupled to the antenna via. An end wall portion 20 is provided at the outer end of the resonator 10,
This end wall portion 20 is a cup-shaped end wall plate that sealingly engages the end of the outer tube 11 of the coaxial resonator 10, as shown in FIGS. It has an engaging green portion 20a. According to the invention, the electrical components C2, C3, C4, L, . . . -, TR of the oscillator are coupled to the end wall portion 201.

The variable capacitor C, consists of an adjusting screw 14 whose inner end is connected to the tubular end 12 of the tubular inner conductor 12.
a and is surrounded by a special insulating member 17. A thin nut 16 is provided on the adjustment screw 14. Other components of the oscillator The rhombus and possibly some of the above-mentioned components, together with connections to other parts, are arranged by a circuit board 15, which is mounted on the adjusting screw 14. The transistor TR, is mounted in a hole in the end wall plate 20.
The essential feature of this invention lies in the way the coupling (C5) is adjusted.

According to the invention, a separate tuning capacitor is not required since there is a coupling between the end of the center conductor 12 of the coaxial resonator 10 and the feedback capacitor C4. transistor T
R, is attached to the end wall portion 20' of the outer tube 11 in order to be able to adjust the position of the capacitor C4 coupled between its base and emitter relative to the asymmetric central conductor 12. The position of this capacitor C4 is adjusted by rotating end wall section 20 about center point 0 in the direction of arrow A in FIG. The correct position of the end wall section 20 can be verified by measuring the power from the oscillator and adjusting it to a certain level. As shown in FIG. 2, the end 12a of the central tube 12 is made asymmetrical with respect to the capacitor C4 and possibly other electrical components by eccentrically centering the center tube with respect to the centerline of the outer tube 11. be done.

This fringe center is indicated by angle Q in FIG. Therefore, when end wall section 20 is turned, capacitor C4 is connected to end 12 of inner tube 12.
The coupling capacitance formed as stray capacitance changes as it approaches or moves away from a. As shown in Figure 4,
The center tube is made asymmetric by the chamfered end 12b of the center tube 12 and, in FIG. 5, by the hole 12c in the end of the center tube 12.

It is also possible to provide several holes, cuts, etc. at the end of the central tube 12. The invention is not limited to the embodiments described above, which have been described merely by way of example, but may be modified within the scope of the inventive concept as defined in the claims.

[Brief explanation of the drawing]

1 is a schematic diagram showing the electrical circuit of the oscillator of the transmitter and the coupling between the transmitter and the coaxial resonator; FIG. 2 is an axial sectional view showing a mechanical embodiment of the transmitter according to the invention; FIG. 4 and 5 are sectional views showing two different embodiments for providing asymmetry in the center conductor of a coaxial resonator; FIG. In the figure, 10 is a coaxial resonator, 11 is an outer tube, 12 is a tubular inner conductor, 14 is an adjustment screw, and 20 is an end wall portion. FIG1 FIG. 2 FIG. 3 FIG. MuFIG5

Claims (1)

Claims: 1. A coaxial resonator stabilized transistor oscillator is provided, the components of this oscillator being mounted on an end wall portion rotatably mounted to the end of the outer tube of the coaxial resonator, and A high-frequency transmitter, in particular for a radiosonde, characterized in that the tightness with which the high-frequency waves are coupled into the coaxial resonator is adjusted by a rotational movement of an end wall section. 2. High frequency transmitter according to claim 1, characterized in that the end wall portion consists of a cup-shaped end wall plate that sealingly engages the end of the outer tube of the coaxial resonator. 3. The tightness of the mutual coupling is adjustable by making the ends of the inner conductor of the coaxial resonator asymmetrical with respect to the center of rotation of the end wall portion. The high frequency transmitter according to item 1 or 2. 4. The high frequency transmitter according to claim 3, wherein the high frequency coupling is mainly performed by stray reactance between the ends of the inner conductor of the coaxial resonator. 5. The end of the tubular inner conductor of the coaxial resonator is chamfered to make this end asymmetrical, a hole or holes are provided, and/or a cut is made, and (
or) A high-frequency transmitter according to claim 3 or 4, characterized in that it is asymmetrical with respect to the center line of the outer tube and the rotation center of the end wall portion. 6. Claims 1, 2, 3, 4, characterized in that the vibration frequency of the oscillator is made adjustable by an adjustable capacitor consisting of a screw inserted into the tubular central conductor of the coaxial resonator. , the high frequency transmitter according to any of Item 5.