JPS6322641B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is a 1/4 device with one end open and the other end grounded.
At least two wavelength resonators and at least two parallel resonators each consisting of a coil and a capacitor.
It is a compact and highly stable device that has improved passband cutoff characteristics, temperature compensation, and a flanged bobbin to reduce the number of turns. The aim is to provide a band wave device.

A conventional bandpass filter of this type will be explained with reference to FIGS. 1 and 2, taking a helical filter as an example. Fig. 1 shows a cross-sectional view of the filter, and Fig. 2 shows its schematic configuration. A 1/4 wavelength resonator is spirally wound around a cylindrical bobbin 2 made of material, and is erected on an insulating substrate 3. One end of the wire is left open, and the other end is connected to a ground terminal implanted on the insulating substrate 3. 4 is 1/4 of each
A metal shielding case made of aluminum or the like having a coupling window 5 for controlling the coupling of the wavelength resonators 1, 1', 1'', 1 and a shielding plate 6. 1', 1'', 1 are stored. In addition, the cylindrical bobbins of the 1/4 wavelength resonators 1, 1 at both ends have input/output windings 7, 7' that inductively couple with the 1/4 wavelength resonators 1, 1 to inject and extract signals. It is provided. Note that 8 is a magnetic core for adjusting the resonance frequency.

Incidentally, the frequency transmission characteristic of this helical filter is as shown by the dotted line in FIG. 7, and the cutoff characteristic is gentle on both the low frequency side and the high frequency side of the passband. In addition, in such a configuration, the length of the copper wire that resonates at 1/4 wavelength is inevitably determined by determining the frequency used, so if you try to reduce the height of the helical filter, the bobbin diameter will increase. It becomes large both vertically and horizontally. On the other hand, if you try to make it smaller in the vertical and horizontal directions, it will become taller, making it impossible to achieve overall miniaturization. In addition, the 1/4 wavelength resonators 1, 1', 1'', 1 generally have a positive temperature coefficient, and even if a magnetic core 9 with a negative temperature coefficient is used, temperature compensation will not be sufficient. However, it had the major drawback of poor temperature characteristics.

The present invention aims to eliminate such conventional drawbacks and provide a bandpass wave generator that improves the cutoff characteristics of the passband, improves the temperature characteristics as well, and can be further downsized. Hereinafter, the band wave device of the present invention will be explained with reference to FIGS. 3 to 6.

FIG. 3 is a sectional view of a bandpass wave generator according to an embodiment of the present invention, and FIG. 4 is a schematic configuration diagram. bobbin 9
In this case, an insulating coated conductive wire such as a polyurethane coated copper wire is divided and wound by shifting the layers by several turns or several tens of turns for each collar 10, thereby configuring the 1/4 wavelength resonators 11 and 11'. ing. Further, the 1/4 wavelength resonators 11 and 11' are installed upright on the insulating substrate 12, and one end of the 1/4 wavelength resonator 11 and 11' is in an open state, and the other end is installed on the insulating substrate 12. connected to the installed earth terminal.

13 is a metal shield case made of aluminum or the like, and this shield case 13 includes 2
The shielding plates 15, 16 and the shield case 13 constitute four chambers 17, 18. The chambers 17 at both ends of the chambers 17 and 18 house the 1/4 wavelength resonators 11 and 11', and are inductively coupled with the 1/4 wavelength resonators 11 and 11' to generate signals. Input winding 1 for injection and extraction
9, an output winding 19' is provided.

On the other hand, in the center chamber 18, a plastic bobbin 9 having a collar 10 is covered with an insulating coated conductor wire such as a polyurethane coated copper wire for each collar 10 (the windings of the 1/4 wavelength resonators 11 and 11'). Coils 20 and 20' are arranged by winding the coils in different layers (considerably less than a wire).
Both ends are connected to terminals implanted on the insulating substrate 12 and taken out to the outside. Furthermore, capacitors 21 and 21' having capacitances that resonate with the coils 20 and 20' are mounted on the lower surface of the insulating substrate 12 housed in the central chamber 18, and both ends of the capacitors 21 and 21' are Said coil 20,2
0' is connected to a terminal on the insulating substrate 12, thereby forming a parallel resonator.

In addition, a coil 20,
Auxiliary windings 22, 2 are made by winding several turns of copper wire or the like around the bobbin 9 so as to be inductively coupled to the auxiliary winding 20'.
2', one end of these auxiliary windings 22, 22' is connected to a ground terminal planted on the insulating substrate 12, and the other end is connected to a terminal planted on the insulating substrate 12 and connected to the outside. The coils 20, 2
0' and one end of a parallel resonator composed of capacitors 21 and 21', and furthermore, auxiliary windings 22 and 22' are also connected to each other. 23 is a magnetic core for adjusting the resonance frequency.

Here, in the band wave device of the present invention, the shielding plate 1 of the chamber 18 on the center side of the shield case 13 is
6 is not normally provided with a coupling window, the two coils 20, 20' are electrically separated, but they are electromagnetically coupled by the connection between the auxiliary windings 22, 22'. In addition, a capacitively coupled trap circuit is formed due to the capacitance between the coils 20, 20' and the shield case 13, and an attenuation pole is generated in the cutoff region on the higher frequency side than the passband. As shown by the solid line in FIG. 7, the frequency transmission characteristics of the bandpass filter can improve the cutoff characteristics on the high frequency side compared to the conventional helical filter shown by the dotted line in the same figure.

Furthermore, although the temperature coefficients of the coils 20 and 20' are positive, by using capacitors 21 and 21' that have negative temperature coefficients that cancel this, temperature compensation becomes possible and temperature characteristics can also be improved. Can be done.

Furthermore, by using the bobbin 9 with the flange 10, the winding distribution capacity of the quarter-wave resonators 11 and 11' can be significantly increased. Since the inductance can be reduced, the number of turns can be significantly reduced.

Furthermore, by using the capacitors 21, 21' in the center, the number of turns of the coils 20, 20' in the center can be significantly reduced. Therefore, as the number of windings is reduced, the diameter of the bobbin 9 can be reduced to make it smaller in the vertical and horizontal directions, and the height of the bobbin 9 can also be lowered, making it possible to downsize the entire band wave device. Moreover, in order to increase the selectivity Q, a copper wire with a thick wire diameter can be used, and reliability can be improved, and the tsuba 10
By employing the bobbin 9 having the following properties, it is possible to stabilize the characteristics.

Furthermore, as in the past, by controlling the size of the coupling window 14, the coupling state can be changed and the bandwidth can also be controlled, so its practical value is great.

Another embodiment of the present invention is shown in FIGS. 5 and 6, and will be described below.

In the embodiment shown in FIG.
In the band wave generator shown in the figure, auxiliary windings 22, 2
A coil 24 is inserted and connected between the input winding 19 and the point where the coils 2' are connected, and this coil 24 is disposed outside the shield case 13.

That is, in this embodiment, a parallel resonant trap circuit is formed by the coupling capacitance between the 1/4 wavelength resonator 11 and the coil 20 and the inductance of the coil 24. An attenuation pole will occur in the side cutoff area,
As shown by the dashed line in FIG. 7, the cutoff characteristics on the low frequency side can also be significantly improved.

Furthermore, by changing the position of the magnetic core 23 inserted into the quarter-wave resonator 11, the coupling with the coil 20 can be changed and the bandwidth can be changed. Furthermore, by changing the position of the magnetic core 23, the coupling capacitance between the 1/4 wavelength resonator 11 and the coil 20 also changes, and the parallel resonance trap frequency due to this coupling capacitance and the coil 24 also changes.
If a magnetic core is inserted in the parallel resonance trap frequency to make it variable, the parallel resonance trap frequency can be controlled to a constant value.

Therefore, there is an advantage that the bandwidth can be changed significantly without changing the winding specifications or the size of the coupling window 14 of the shield case 13. Furthermore, to change the bandwidth significantly, coil 2
0, the winding position and winding division ratio of the 1/4 wavelength resonators 11 and 11' can be changed, or the size of the coupling window 14 of the shield case 13 can be changed as usual.

Furthermore, in the embodiment shown in FIG. 6, in addition to the embodiment in FIG. However, two attenuation poles are provided on the low-frequency side and two on the high-frequency side of the passband to significantly improve the cutoff characteristics near the passband, and the frequency transmission characteristics are as shown by the two-dot chain line in Figure 7. become.

The case shown in FIG. 6 has the advantage that by appropriately changing the inductance values of the coils 24 and 25, the cutoff characteristics on the low frequency side of the passband can be freely changed, and bounce due to traps can also be controlled.

By the way, in the above embodiment, the central coil 2
0, 20' and capacitors 21, 21' are separated by a shield plate 16, but if a window is provided in this shield plate 16, the distribution between the coils 20, 20' Due to the effect of capacitance, the cutoff characteristics on the high frequency side of the passband become gentler.
That is, by changing the size of the window provided in the shield plate 16, the high frequency side blocking characteristics can be changed arbitrarily.

Further, the bobbin 9 having the collar 10 is attached to the insulating substrate 12.
If each coil is made to be independent, the windings can be wired individually, there is no need for compound or wax for wire fixing, and the moisture resistance can be greatly improved.

In addition, when there are many windings of the input/output windings 19 and 19', it is possible to further reduce the size by using layer-shifting and split windings as in the case of the 1/4 wavelength resonators 11 and 11'. Similarly, the coils 24 and 25 can also be made smaller by employing layer-shifting split windings.

As described above, the bandpass filter according to the present invention can provide excellent passband cutoff characteristics, can be made smaller, and can be provided as a video intermediate frequency filter for television receivers. Can be done.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional helical filter, Fig. 2 is a schematic configuration diagram of the same filter, Fig. 3 is a sectional view showing a bandpass filter according to an embodiment of the present invention, and Fig. 4 is a sectional view of a bandpass filter according to an embodiment of the present invention. FIG. 5 and FIG. 6 are schematic diagrams of band wave generators according to other embodiments of the present invention, respectively, and FIG. 7 is a frequency transmission characteristic diagram of a conventional wave generator and a wave generator according to the present invention. be. 9...Bobbin, 10...Tsuba, 11, 11'...
1/4 wavelength resonator, 13...shield case, 14
...Coupling window, 16...Shield plate, 19...Input winding, 19'...Output winding, 20, 20'...Coil, 21, 21'...Capacitor, 22, 22'...
...Auxiliary winding, 24, 25...Coil.

Claims (1)

[Claims] 1 At least two 1/4 wavelength resonators that are constructed by winding wires on a bobbin with multiple flanges and that have one end open and the other end connected to a shield case, and these 1/4 wavelength resonators. at least two parallel resonators each consisting of a coil and a capacitor configured by winding the windings on a bobbin with a plurality of flanges in an electric field, and inductively coupled to the parallel resonators. auxiliary winding,
It has an input winding and an output winding that are inductively coupled to the 1/4 wavelength resonator and configured by layer-shifting split windings on the same bobbin as the 1/4 wavelength resonator, and the parallel resonators are connected to each other. They are electrically separated by a shield case, and one end of the parallel resonator is insulated from the shield case and connected to the outside by connecting them to each other.
A band wave generator, characterized in that one end of the auxiliary winding is connected to a shield case, and the other end is connected to one commonly connected end of the parallel resonator.