JPS605646Y2 - UHF TV Jiyeon Chiyuna - Google Patents

Description

[Detailed explanation of the invention] This invention is an LJHF that attaches various parts to a printed circuit board.
It concerns a television tuner.

First, a conventional IJHF television tuner of this type will be explained with reference to FIG.

In FIG. 1, 1 is a shield case, and a printed circuit board 2 is housed within this shield case 1. As shown in FIG.

Reference numeral 3 denotes a partition plate, and a local oscillation circuit shown in FIG. 2 is constructed in a section surrounded by the partition plate 3 and the shield case 1.

This local oscillation circuit includes electronic components such as a transistor 4, resistors 5 and 6, a coil 7, and a capacitor 8 on a printed circuit board, and a resonant line 9 and a coupled line 10 formed by punching out a metal plate.
The copper foil printed pattern formed on the printed circuit board 2 connects each electronic component by inserting it into a hole in the printed circuit board 2 and soldering it.

However, when electronic components are inserted and soldered directly to the printed circuit board 2 as described above, the inductivity of the printed circuit board (mainly phenol-based, epoxy-based, etc.) changes under the influence of temperature and humidity, causing local oscillation. It had the disadvantage of lacking frequency stability.

The present invention eliminates the above-mentioned conventional drawbacks and provides a UHF television tuner that is not affected by the printed circuit board.An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

FIG. 3 shows a local oscillation circuit, in which the local oscillation circuit is assembled on a metal plate 11, which serves as a common wiring section, with both sides bent in the same direction.

Reference numeral 12 denotes a resonant line formed by punching out the metal plate 11 in a U-shape, and one end of this resonant line 12 is attached to a grounding capacitor 13 attached to the metal plate 11.

Further, a variable capacitance diode 14 is interposed between the other end of the resonant line 12 and the metal plate 11.

15 is a grounded capacitor attached to the resonant line 12, and this grounded capacitor 15 is connected to a transistor 16,
A capacitor 17 is connected.

18 is a resistor connected to the transistor 16 and capacitor 17; 19 is a trimmer plate formed by cutting and raising the metal plate 11;

As described above, a local oscillation circuit is constructed on the metal plate 11.

FIG. 4 shows a state in which the local oscillation circuit unit shown in FIG. The metal plate 11 is inserted into the hole, and the metal plate 11 is fixed to the printed circuit board 2 by soldering or the like, and the metal plate 11 and the copper foil printed pattern of the printed circuit board 19 are electrically connected.

As described above, in the above embodiment, the electronic components constituting the local oscillation circuit are not directly attached to the printed circuit board, but are assembled on the metal plate.
This has the advantage that the printed circuit board is not affected by changes in humidity and the like, and the local oscillation frequency is stabilized.

Further, according to this embodiment, the local oscillation circuit unit can be manufactured separately, which has the advantage of improving productivity.

Although the above embodiment is an example of a local oscillation circuit, the influence of the printed circuit board can be removed by applying it not only to the local oscillation circuit but also to other circuits of a UHF television tuner, such as input circuits and double-tuned circuits. It is possible.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the main parts of a conventional UHF television tuner, Fig. 2 is an electrical circuit diagram of a local oscillation circuit of a general A perspective view of the oscillation circuit unit, and FIG. 4 is a sectional view showing the local oscillation circuit unit housed in a shield case. 1... Shield case, 2... Printed circuit board. , 3... Partition plate, 11... Metal plate, 12... Resonance line, 13, 15...
・Grounded capacitor, 16... Transistor, 1
7... Capacitor, 18... Resistor, 1
9...Trimmer plate, 20...Protrusion piece.

Claims (2)

[Scope of utility model registration request] (1) Install various parts on a printed circuit board, connect each of the above parts to the printed pattern of the printed circuit board, and then
In a UHF television tuner constituting an HF tuner circuit, the electronic components and resonant line constituting the local oscillation circuit of the IJHF tuner circuit are arranged on a metal plate serving as a common wiring part and forming a predetermined circuit pattern. The UHF is constructed by connecting the metal plate of the local oscillation circuit unit to the printed circuit board, and electrically connecting the printed pattern of the printed circuit board and the metal plate. television tuner. (2) Utility Model Registration In the UHF television tuner according to claim 1, a projection is formed at the lower end of the side of the metal plate whose side is bent, and the projection is inserted into a hole in a printed circuit board. , an LIHF television tuner in which the metal plate is attached to the printed circuit board by soldering.