JPS61244098A - Electronic tuner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electronic tuner used for UHF and VHF broadcast reception.

Conventional technology In general, in high frequency equipment such as electronic tuners, UHF,
Mainly equipped with leaded parts such as vHF circuit (Q-trans 7, , U.H.
It has a structure in which the resistor chip, capacitor chip, inductor chip 6, etc. of the VHF circuit are soldered.

In addition, since the UHF and VHF input tuning, amplification, crotch, rooting, and mixing function circuits are configured on the same side of the printed circuit board, shielding between UHF and UHF and shielding between each circuit is performed. The structure is partitioned by many shield plates 6 such as thin iron plates.

However, with this type of structure, as shown in Figure 3, the UHF and VHF circuit coils/coins are installed on the front side of the electronic tuner.
Since relatively large components such as the I/2, transformer 1, leaded capacitor 3, and leaded resistor 4 are mounted, the size of the tuner in the vertical and horizontal directions becomes large. In addition, in order to drive the electronic tuner, the UHF and VHF circuits are supplied with a power supply voltage for the switching diode for band switching, a power supply voltage for AGC, a power supply voltage for Ayc, a power supply voltage for the variable capacitance diode for tuning, etc. Since this is done through the discon terminal 7, the left half of the diagram is UHF and the right half is VHF.
In this case, in order to supply power to the UHF side, it is necessary to cross the VHF circuit wiring section, which becomes a factor that makes the circuit even more complicated.

In addition, the frame 8 must include a shield plate 6 between the UHF circuit and the VHF circuit, and a shield plate e for each functional circuit of UHF and VHF, resulting in a very complicated partition structure as shown in Figure 4. , which is large and difficult to manufacture.

Also, when grounding from a point other than the side of the printed circuit board circuit, it is not necessary to take out the contact piece 9 from the frame partition and solder it to the board, or add another connection piece to connect the ground to the frame. It is true.

Problems to be Solved by the Invention As described above, the conventional configuration has the disadvantage of having a complicated structure. Therefore, the present invention provides an electronic tuner that can eliminate such drawbacks.In order to solve the above problems, the present invention has developed
The circuit section is roughly divided between two printed circuit boards, and a shield plate for UHF and VHF shielding functions and a ground connection function for each circuit is constructed between each printed circuit board.

Operation With this configuration, the UHF circuit section of the electronic tuner and the VHF
When configuring circuit parts on the same printed circuit board, UH
The partition structure of the frame, such as the shield between F and UHF, and the shield for each UHF and VHF functional circuit, is very complex and large, but in the present invention, the UHF and VHF circuits are separated by almost two printed circuit boards. In order to
, there is no mutual radio wave interference between the VHF circuits, and the structure can be extremely simplified.

Example· An embodiment of the present invention will be described below based on the accompanying drawings.

In FIG. 1, an electronic tuner frame 11 has openings on both sides, and both openings are combined with shield plates 12 that form sections for each circuit block within the frame 11.

Also, approximately in the center of the frame is a single-sided printed circuit board 13.
14 is attached, and on one side of the printed circuit board 12, high frequency concave components 16 such as a coil 14 of either UHF or VHF, a resistor chip, a capacitor chip, etc. are mounted. Also, on the printed circuit board 12 side, mainly UHF
, VHF high frequency components are mounted.

And printed circuit board 12.13 (7) UHF, VHF
In order to prevent radio wave interference occurring between each tuning circuit, crotch circuit, and oscillation circuit, between the printed circuit boards 12 and 13,
A shield plate 16 having an electromagnetic shielding effect such as a copper foil, a copper plate, or an iron plate is interposed on the entire surface or in necessary parts.

FIG. 2 is a sectional view showing another embodiment of the invention. In this embodiment, an L-shaped bent piece 17 is formed on a part of the outer periphery of the shield plate 1e, and the ground potential is easily taken out from the frame 11 by taking it out and soldering it to the component mounting surface of the printed circuit board 13.

In addition, in the case of electronic tuners, many circuits are grounded on the circuit wiring for input tuning, amplification, single oscillation between the legs, and mixed circuits. By setting 18 and soldering it to the ground patterns of the printed circuit boards 12 and 13, it is possible to easily make the ground connection.

Next, other embodiments of the present invention will be described.

FIG. 3 shows an embodiment in which a tuner that is even more compact than the embodiment shown in FIG. , a capacitor chip, etc. are mounted, and a thin insulating plate 19 is inserted as shown in the upper half of the figure to prevent contact between the electrodes of each chip, the terminal of the coil, and the shield plate 1e. As shown in the lower half of the figure, sufficient space 20 is provided to prevent touching. The other structures are the same as those in FIG. 1.

More than the effects of the invention, according to the present invention, (1) Since the UHF circuit and the /HF circuit are separated into almost separate printed circuit boards, it is possible to prevent radio wave interference between the UHF and VHF circuits, and improve the tuner's performance characteristics. I can do it.

(2) By setting a shield plate between the printed circuit boards, the effect of 1 can be further improved, and the ground can be reliably connected to any position on the printed circuit board from the thin iron shield plate. Therefore, circuit formation becomes simple.

(3) UHF, V Since the power supply wiring for driving the H7 circuit is separated for UHF and VHF, the power supply wiring circuit is simplified.

(4) Also in the frame structure, it is sufficient to have a partition for only a VHF circuit or a partition for only a UHF circuit on each of the upper or lower surfaces, resulting in a very simple frame partition structure.

It has the following effects.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an electronic tuner structure according to one embodiment of the present invention, FIGS. 2 and 3 are longitudinal sectional views of another embodiment of the present invention, and FIG. 4 is a perspective view showing a conventional structure. be. 11...Frame, 12.13...Printed circuit board, 12, 1 e---shield plate,
14... Coil. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 figure
7---Te1 score If--7Moum+2. lff-11 pudding y fu4 and jf;-11 seal VR 2ndryJ Figure 3 4z

Claims (2)

[Claims] (1) First and second printed circuit boards are held in a metal frame having openings on both sides, UHF tuner circuit components are mainly mounted on the first printed circuit board, and UHF tuner circuit components are mounted on the second printed circuit board. The electronic tuner is mainly equipped with VHF tuner circuit components, and further includes a shield plate interposed between the first and second printed circuit boards. (2) The electronic tuner according to claim 1, wherein a contact piece of an arbitrary shape is formed from the shield plate and connected to the ground point of the first and second printed circuit boards and the ground point of the frame, respectively.