JPS634367B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polarized mechanical filter equipped with an interlace connector for reverse phase coupling.

A mechanical filter is a band pass filter that transmits electrical signals through ultrasonic vibrations, and its Q (sharpness) is extremely high compared to filters that use electrical elements such as L and C. It has various advantages such as high stability and miniaturization. Therefore, they are used, for example, as channel filters and signal filters in communication path converters, or as filters in navigation receivers and automatic train control devices. Particularly in recent years, with advances in technology, various ideas have been made for wideband filters and narrowband filters.

In recent years, a method for configuring mechanical filters with polarity has been developed for the purpose of downsizing mechanical filters by reducing the number of constituent elements and improving group delay time characteristics, and has already been put into practical use in the aforementioned channel filters and the like.

The mechanical filter has at least three polar configurations.
In a mechanical filter consisting of a plurality of mechanical oscillators and a main coupler connected in phase to each of these mechanical oscillators, one mechanical oscillator and another mechanical oscillator that is not adjacent to it are further separated. This is done by using one interlacing connector to connect them so that they are in phase or out of phase with each other.

When configuring a polarized mechanical filter, the number of mechanical oscillators that exist between two mechanical oscillators connected by the above-mentioned interleaved coupler is usually one or two. many. for example,
When there is only one mechanical oscillator in the middle, if the interleaved couplers are connected in phase with each other, a pole will appear on the high-frequency side of the passband, and if they are connected in opposite phases, a pole will appear on the low-frequency side. When there are two mechanical oscillators in the middle, if the interlacing couplers are connected in opposite phases to each other, one pole will appear on the high-frequency side and one on the low-frequency side of the passband.

By using interlaced connectors in this manner, a polarized mechanical filter can be constructed. The polar configuration of the mechanical filter is advantageous in that it can satisfy the originally contradictory characteristics of improving selectivity characteristics and group delay time characteristics of the filter, as well as demands for miniaturization. In general, increasing the number of constituent elements of a filter improves its selectivity characteristics, but conversely, the group delay time increases, and furthermore, the filter itself becomes larger due to the increase in the number of elements. According to the polarized mechanical filter, the number of elements can be significantly reduced while satisfying the above-mentioned characteristics requirements, thereby meeting the demand for miniaturization of electronic components.

As such a polarized mechanical filter,
Several formats have already been proposed. These can be roughly divided into two types based on their construction methods.

FIG. 1 is a perspective view showing the structure of a conventional polarized mechanical filter using three torsionally vibrating mechanical oscillators. In the figure, 1, 2, and 3 are mechanical oscillators that vibrate in a torsional first-order vibration format, 4 is a main coupler that couples mechanical oscillators 1, 2, and 3 in the same phase, and 5 is a mechanical oscillator that connects mechanical oscillator 2. This is an interlaced coupler that connects mechanical vibrators 1 and 3 in opposite phases to each other. Further, 6 and 7 respectively indicate a node of torsional primary vibration and a vibration displacement.

In the mechanical filter shown in FIG. 1, the main coupler 4 coupled in phase is connected to the mechanical oscillators 1, 2, and 3 at almost right angles, whereas the interleaved coupler 5 is It is connected diagonally to the vibrators 1 and 3.
This is to obtain an anti-phase coupling by connecting points where the displacement directions of the torsional primary vibrations of each mechanical vibrator are opposite to each other. In this mechanical filter, a pole appears on the lower side of the passband.

The advantage of the polarized mechanical filter of the type shown in Figure 1 is that all the mechanical oscillators vibrate in the same order and in the same vibration form, so the dimensions and shape of each mechanical oscillator are almost the same. The advantage is that only one type of mechanical vibrator is required when assembling the filter. However, the polarized mechanical filter of this configuration is difficult to manufacture because the interleaved coupler is connected diagonally to the mechanical vibrator as described above, and it is also difficult to maintain dimensional accuracy. be.

FIG. 2 is a perspective view showing the structure of a conventional polarized mechanical filter using a bending vibration type mechanical vibrator and a torsion vibration type mechanical vibrator. In the figure, 8 is a mechanical vibrator that performs secondary vibration of the bending vibration type, 9 and 10 are mechanical vibrators that perform the primary vibration of the torsional vibration type, and 11 is a mechanical vibrator that has the same phase as the mechanical vibrators 8, 9, and 10, respectively. is an interleaved connector that joins to . 13 and 14 are respectively bent second
Next, represent the nodes of the first torsional vibration, and further 1
5 and 16 each represent a vibration displacement. In this mechanical filter as well, the pole appears on the lower side of the pass band.

The advantage of the polarized mechanical filter of the type shown in FIG. Easy to weld;
Furthermore, since the structure is relatively simple, it is easy to manufacture. However, since the polarized mechanical filter of this configuration uses mechanical oscillators with different vibration types, they not only have different mechanical shapes and dimensions, but also
Materials also differ due to frequency temperature coefficient etc.2
Disadvantages include that different types of mechanical vibrators must be prepared and that two connectors must generally be connected to both sides of the mechanical vibrator.

The present invention aims to eliminate such drawbacks of the prior art, and its purpose is to provide a main coupler that can be constructed only from mechanical vibrators of the same vibration type and made of the same material, and that transmits signals in the same phase. An object of the present invention is to provide a polarized mechanical filter in which the and the interleaved couplers provided for forming poles are arranged approximately at right angles to the mechanical oscillator, and are therefore easy to manufacture and maintain accuracy. be. In order to achieve this object, the polarized mechanical filter of the present invention includes at least three mechanical oscillators arranged so that their long axes are parallel to each other, and a main coupling that couples the mechanical oscillators in phase. and an interlaced coupler that couples at least one pair of non-adjacent mechanical oscillators among the mechanical oscillators in opposite phases,
The pair of mechanical oscillators connected by the interlaced coupler vibrate in the same vibration form of the fundamental vibration order, have substantially the same dimensions and shapes, and are arranged offset from each other in the longitudinal direction, It is characterized in that both the coupler and the interleaved coupler are connected at substantially right angles to the mechanical vibrator.

Examples will be described in detail below.

FIG. 3 is a diagram showing the structure of an embodiment of the polarized mechanical filter of the present invention. This figure shows an example in which the present invention is applied to a mechanical filter constituted by a torsionally vibrating mechanical vibrator. FIG. 3A is a perspective view showing the structure of the polarized mechanical filter of this embodiment. In the same figure, 17,1
8 and 19 are mechanical vibrators that perform primary vibration in a torsional vibration type; 20 are mechanical vibrators 1 that perform longitudinal vibration;
a main connector that connects 7, 18 and 19 in phase,
21 performs longitudinal vibration, and mechanical oscillators 17 and 19
22 and 23 represent the nodes and vibration displacements of a torsional vibration type mechanical vibrator, respectively. Further, the arrow indicates the direction of displacement, and the x mark indicates the connection point between the coupler and the mechanical vibrator. In addition, mechanical vibrator 1
The geometries of 7, 18 and 19 are made to be approximately equal to each other. The feature of this filter is that in order to realize the attenuation pole as mentioned above, the pair of mechanical oscillators 17 and 19 are shifted from each other in the length direction of the mechanical oscillators, so that the two couplers are arranged on the same plane. They can be connected parallel to each other and approximately at right angles to the mechanical vibrator. In this embodiment, the lengthwise deviation between the pair of mechanical vibrators is approximately 1/4. Here l is the length of mechanical vibrators 17 and 19.

FIG. 3B is a top view of the mechanical filter shown in FIG. 3A. As seen in the figure, the coupling elements 20 and 21 are arranged substantially parallel to each other and are connected to the mechanical oscillators 17, 18 and 19 at substantially right angles.

FIG. 4 is a diagram showing the structure of another embodiment of the polarized mechanical filter of the present invention. This figure shows an example in which the present invention is applied to a mechanical filter composed of a longitudinal vibration type mechanical vibrator. FIG. 4A is a perspective view showing the structure of the polarized mechanical filter of this embodiment. In the same figure, 24,
25 and 26 are mechanical oscillators that perform first-order vibration in a longitudinal vibration format; 27 is a main coupler that performs flexural vibration and couples the mechanical oscillators 24, 25, and 26 in phase; and 28 is a mechanical oscillator that performs flexural vibration and It is an interleaved coupler that couples the oscillators 24 and 26 in opposite phases,
29 and 30 represent the nodal point and vibration displacement of a longitudinal vibration type mechanical vibrator, respectively. Further, the arrow indicates the direction of displacement, and the x mark indicates the connection point between the coupler and the mechanical vibrator. Note that the shapes and dimensions of the mechanical vibrators 24, 25, and 26 are made to be approximately equal to each other. Further, in this embodiment, the lengthwise deviation between the pair of mechanical vibrators 24 and 26 is approximately 1/4. Here, L is the length of mechanical vibrators 24 and 26.

FIG. 4B is a top view of the mechanical filter shown in FIG. 4A. As can be seen in the figure, the coupling elements 27 and 28 are arranged substantially parallel to each other, and are connected to the mechanical oscillators 24, 25 and 26 at substantially right angles.

FIG. 5 is a diagram showing the structure of a third embodiment of the polarized mechanical filter of the present invention. This figure shows an example in which the present invention is applied to a mechanical filter composed of a bending vibration type mechanical vibrator. FIG. 5A is a perspective view showing the structure of the polarized mechanical filter of this embodiment. In the same figure,
31, 32 and 33 are mechanical oscillators that perform primary vibration in the form of bending vibration; 34 is a main coupler that performs longitudinal vibration and couples the mechanical oscillators 31, 32 and 33 in phase; and 35 is a main connector that performs longitudinal vibration. This is an interlaced coupler that performs mechanical vibration to couple the mechanical vibrators 31 and 33 in opposite phases, and 36 and 37 represent the nodes and vibration displacements of the mechanical vibrators in the bending vibration type, respectively. Further, the arrow indicates the direction of displacement, and the x mark indicates the connection point between the coupler and the mechanical vibrator. Note that the shapes and dimensions of the mechanical vibrators 31, 32, and 33 are made to be approximately equal to each other.

Further, in this embodiment, a pair of mechanical vibrators 3
The lengthwise deviation length between 1 and 33 is approximately 1/4. where l is the mechanical oscillator 31 and 33
is the length of

FIG. 5B is a top view of the mechanical filter shown in FIG. 5A. As seen in the figure, the connectors 34 and 35 are arranged substantially parallel to each other, and are connected to the mechanical oscillators 31, 32, and 33 at substantially right angles.

As explained above, according to the polarized mechanical filter of the present invention, the polarized mechanical filter can be configured only with mechanical vibrators having the same vibration type, the same material, and the same size and shape, which is economically advantageous. The main coupler, which transmits signals in the same phase, and the interleaved coupler, which is provided to form the poles, are arranged approximately at right angles to the mechanical vibrator, making it easy to manufacture. , and excellent effects such as ease of maintaining accuracy can be obtained.

In the above-described embodiments, the present invention was applied to a mechanical filter consisting of mechanical vibrators of three typical types of vibration: torsional, longitudinal, and flexural. The invention is not limited to the above embodiments, but can be applied to all types of vibration.

Furthermore, in the above-mentioned embodiment, the lengthwise deviation length between the pair of mechanical vibrators was set to approximately 1/4 (l: length of the mechanical vibrator), but the present invention is limited to this deviation length. However, any length may be used as long as the present invention is applicable to the offset length.

Furthermore, although each of the above-mentioned embodiments is a case in which one pole is provided on the low-frequency side of the pass band, the present invention is not limited to this case, and the present invention is not limited to this case. When the number of mechanical oscillators present in the middle of the oscillators is two, one pole can be provided on each of the low-frequency side and the high-frequency side of the passband. Furthermore, by partially applying a plurality of interlace connectors shown in the above embodiment to a mechanical filter consisting of multiple elements,
It is also possible to provide multiple poles. It goes without saying that the mechanical vibrator constituting the mechanical filter may be either a resonator or a transducer.

As described above, the polar mechanical filter according to the present invention has a wide range of applications and is excellent in manufacturability, so it can be said to be a filter of extremely high industrial value.

[Brief explanation of the drawing]

1 and 2 are perspective views each showing the configuration of a conventional polarized mechanical filter, and FIGS. 3 to 5 are views each showing the configuration of an embodiment of the polarized mechanical filter of the present invention. be. 1, 2, 3... mechanical oscillator, 4... main coupler,
5...Interlaced coupler, 6...Node, 7...Vibration displacement, 8,9,10...Mechanical oscillator, 11...Main coupler, 12...Interlaced coupler, 13,14...
...Node, 15, 16... Vibration displacement, 17, 18,
19... Mechanical vibrator, 20... Main coupler, 21...
...Interlaced coupler, 22...Node, 23...Vibration displacement, 24, 25, 26...Mechanical oscillator, 27...
...Main connector, 28... Jump connector, 29...
Node, 30... Vibration displacement, 31, 32, 33...
Mechanical vibrator, 34...main coupler, 35...jump coupler, 36...node, 37...vibration displacement.

Claims (1)

[Claims] 1 At least three mechanical oscillators arranged so that the directions of their long axes are substantially parallel, a main coupler that couples each of the mechanical oscillators in the same phase, and at least one pair of each of the mechanical oscillators. In a polarized mechanical filter, the pair of mechanical oscillators connected by the interleaved coupler have the same fundamental vibration order. vibrates in a vibrating manner, has substantially the same dimensions and shapes, and is arranged offset from each other in the longitudinal direction, and the main coupler and the jump coupler are both connected at a substantially right angle to the mechanical vibrator. A polarized mechanical filter that is characterized by: