JPS607849B2 - Interference rejection filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an interference wave removal method that is used to remove signals (interference waves) in unnecessary frequency bands or specific frequencies and send out only the desired signals, for example, when receiving television signals. The present invention relates to a filter, and more particularly to an interference wave removal filter capable of removing a plurality of interference waves.

In conventional interference wave removal filters of this type, in order to enhance the interference wave removal effect, each filter element was constructed by connecting a plurality of filter elements in series for each interference wave. Since there is sufficient space between them, there is a problem in that the overall shape of the filter becomes large.

Furthermore, if the spacing is shortened, adjacent filter elements will interfere with each other and the attenuation characteristics will be different from the expected ones, creating a problem in which it becomes impossible to remove interference waves. The present invention is designed to solve the above problems, and it is possible to eliminate interference waves extremely effectively, and also to reduce the overall size, and even with such a small size, it is possible to obtain good performance. The aim is to provide a filter for eliminating interference waves.

The drawings showing the embodiments of the present application will be described below. The substrate up to h' is made of an insulating material. Reference numeral 2 denotes a ground conductor attached to the substrate 1, which is generally made of copper foil.

Reference numeral 3 denotes an input terminal, which is constructed in a well-known manner with a center conductor connecting portion 3a and an outer conductor connecting portion 3b to enable connection of a coaxial cable.

4 is the output terminal, and the center conductor connection part 4a is connected to the input terminal and the same machine.
and an external conductor connection portion 4b.

Next, reference numerals 5, 62, . . . indicate a plurality of filter elements arranged on the substrate, each of which is arranged equally. These filter elements 5, 52...・．． In the figure, numeral 6 denotes a bobbin made of steatite (referred to as a relay terminal) with a metal-plated end surface, and is erected from the substrate 1 by soldering the end surface to the ground conductor 2. Note that the bobbin 6 has a columnar shape such as a cylinder or a rectangular column. In some cases, a resin material is also used. 8 is the bag 1 wound on bobbin 6
In the secondary coil, a conducting wire (for example, polyurethane copper wire or polyester copper wire) with an insulating coating is used.

A secondary coil 9 is inductively coupled to the primary coil, one end of which is soldered to the end surface of the bobbin 6, and the other end soldered to the ground conductor 2.

A capacitor 10 is a ceramic capacitor, one end of which is soldered to the above-mentioned end face, and the other end of the capacitor is soldered to the earth conductor 2.

Note that a variable capacitor may be used for this purpose. Each of the filter elements 5, 52 with the above configuration...
In the case of the interference wave removal filter of this example, which removes the signals of the 28th channel and the 36th channel of the television channel as interference waves, as shown in FIG. Element 5,,52
is for the 28th channel, and their resonance frequencies are f, respectively.
, f2, and the filter elements 53 and 54 are for the 36th channel, and their resonance frequencies are also f4. That is, filter elements designed to remove interference waves of different channels are arranged to be adjacent to each other; in other words, filter elements designed to remove interference waves of the same channel are arranged not to be adjacent to each other. This order can be changed to other different orders if the above conditions are met.
For example, it may be 53, 52, 54, 5, etc. in order from the input side. Further, the spacing between the filter elements is preferably such that the spacing between the filter elements for removing the same interference wave is approximately 1/4 of the wavelength of the interference wave. 11,
Reference numeral 11... is a connecting wire, which is constructed using a conductive wire that is unified with the primary coil.

Further, as shown in the figure, by placing it close to the ground conductor 2, its own impedance becomes almost equal to the impedance of the transmission system, so that good transmission characteristics can be obtained. With the above configuration, when the target signal and interference waves mixed with it enter the input terminal 3,
The target signal passes through the primary coil 8 in each filter element 5, 52...... while the interference wave passes through the primary coil 8 in each filter element 5, 52...... It is removed by coupling with the secondary coil 9 and resonance between the secondary coil 9 and the capacitor 0.

Therefore, only the target signal is output from the output terminal 4. Although the case where there are two interference waves has been described above, if there are more interference waves, the number of elements may be increased accordingly. Further, although an example is shown in which two elements are used for each interference wave, a larger number of elements may be used. In these cases as well, it is sufficient to ensure that elements for the same interference wave are not adjacent to each other. Furthermore, as mentioned above, when removing not only TV signals but other interference waves, it is necessary to use multiple elements whose resonant frequencies are adjusted for each interference wave, and arrange the elements so that they are not adjacent to each other. do it.

In this case, even if the resonant frequencies of each of the plurality of elements are separated, such as f and f2, or originally f4,
Or they may be the same. As described above, in the present invention, a plurality of filter elements 5, 62, 53, 54 are provided for each of a plurality of interference waves to be removed.
, so when trying to remove multiple interference waves, it has the advantage of being able to remove all of them extremely effectively.

Moreover, even if a plurality of filter elements are used to remove each interference wave, the elements are arranged in an order in which the elements are not adjacent to each other in order to remove the same interference wave. Therefore, when manufacturing an interference removal filter, each filter element can be packed into a narrow space, and the overall shape of the interference removal filter can be made compact. There is. Also, since each element is connected in the order shown above, even if the elements are arranged close together as shown above, there should be enough space between the elements to eliminate the same interference waves. This makes it possible to cut off mutual electromagnetic edges, which has the effect of accurately removing the interference waves to be removed (without shifting the frequency band to be removed).

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is a perspective view, FIG. 2 is an enlarged view of main parts, FIG. 3 is a circuit diagram, and FIG. 4 is a damping characteristic diagram. 1...Substrate, 5, to 54...Filter element. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. Interference wave removal configured by connecting a plurality of filter elements in series, and by passing a signal through the filter elements in order, a plurality of interference waves contained in the signal are removed by the filter element. In the filter, a plurality of the above-mentioned filter elements are provided for each interference wave to be removed, and the arrangement of these filter elements is such that one filter element for removing interference waves is arranged so that other filter elements are arranged between each other. An interference wave removal filter characterized in that filter elements for interference wave removal are arranged in an intervening order.