JPS6016112Y2 - Multi-band electronic tuning tuner device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a multi-band electronic tuning tuner device used in television receivers and the like, and is particularly designed to have a simple configuration so as not to receive signals in unnecessary bands.

Currently, the frequency band of television broadcasting spans multiple bands.

In Japan, it is divided into a low channel band from the 1st channel to the 3rd channel and a high channel band from the 4th channel to the 12th channel, and the frequency band between the low channel band and the high channel band is used for television. John is using it for things other than broadcasting.

Particularly in some countries, such as Canada, the frequency band immediately below the high channel band is used for CATV and the like.

On the other hand, in the conventional electronic tuning tuner device, as shown in FIG.
is connected to the movable element 3a of the variable resistor 3 inserted between the power supply terminal 2 to which a positive DC voltage is supplied and the ground, and the electronic tuning tuner device 1 is controlled by the control voltage obtained from the movable element 3a. The receiving frequency is controlled by controlling the capacitance value of the capacitive diode.

Further, the electronic tuning tuner device 1 is provided with a high channel band switching voltage supply terminal 4h and a low channel band switching voltage supply terminal 41, and the high channel band switching voltage is supplied to the high channel band switching voltage supply terminal 4h. When the electronic tuning tuner device 1 is selected, the electronic tuning tuner device 1 is switched so that the high channel band can be selected, and the low channel band switching voltage supply terminal 41 is switched so that the high channel band can be selected.
is supplied with the low channel band switching voltage.

Sometimes the electronic tuner device 1 is configured to be switched to select a low channel band.

In the conventional electronic tuning tuner device as shown in FIG. 1, the high channel band switching voltage is supplied to the high channel band switching voltage supply terminal 4h to select a high channel band. The relationship between the control voltage obtained at the movable element 3a of the variable resistor 3 and the reception frequency when the movable element 3a of the variable resistor 3 is moved is linear as shown in FIG. Mover 3
The relationship between the control voltage obtained in A and the reception frequency is designed with a margin, so it is possible to receive signals in unnecessary frequency bands lower than the high channel band, especially in CATV in Canada. There was an inconvenience that it was not possible to receive such messages.

In view of the above points, the present invention has a simple configuration that makes it impossible to receive signals in unnecessary frequency bands.

Hereinafter, one embodiment of the multi-band electronic tuning tuner device of the present invention will be described with reference to FIG.

In FIG. 3, parts corresponding to those in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

In this example, the high channel band switching voltage supply terminal 4h to which the high channel band switching voltage, which is a positive DC voltage, is supplied is grounded through a series circuit of a resistor 5, a variable resistor 6, and a resistor 7. , the movable element 6 of this variable resistor 6
In a, the minimum voltage ■ of the control voltage required for high channel band selection.

(Hereinafter referred to as reference voltage V.

That's what it means. ). The movable element 6a of the variable resistor 6 is connected to the anode of the diode 8, the cathode of this diode 8 is connected to the control voltage supply terminal 1a for tuning of the electronic tuning tuner device 1, and the control voltage supply for tuning The terminal 1a is connected to the movable element 3 of the variable resistor 3 via the resistor 9.
Connect to a.

The rest of the structure is the same as in FIG. Since the present invention is configured as described above, when the high channel band switching voltage is supplied to the high channel band switching voltage supply terminal 4h, the electronic tuning tuner device 1 is able to tune the high channel band as in the conventional case. The desired channel of the high channel band can be selected by adjusting the control voltage obtained at the movable element 3a of the variable resistor 3 (in this case, the control voltage is the lowest voltage (2).

Because of the above, diode 8 is non-conductive.

). Further, the control voltage obtained at the movable element 3a of this variable resistor 3 is the lowest voltage V of the control voltages necessary for high channel band selection.

When the voltage is below, the diode 8 becomes conductive, so that the control voltage supplied to the channel selection control voltage supply terminal 1a of the electronic tuning tuner device 1 is the standard obtained by the movable element 6a of the variable resistor 6, as shown in FIG. Voltage V.

Not less than.

That is, the control voltage supplied to the channel selection control voltage supply terminal 1a is this lowest voltage V.

It will be clamped to prevent the following.

Therefore, in this case, signals in unnecessary frequency bands in the frequency range lower than the high channel band are not received.

Further, in the example of FIG. 3, when the low channel band switching voltage is supplied to the low channel band switching voltage supply terminal 41, the diode 8 is always non-conducting, so it operates in the same manner as before, and the desired low channel band is switched as before. channels can be selected.

As described above, according to the present invention, it is possible to prevent signals in unnecessary bands from being received with a relatively simple configuration.

Also, according to the present invention, a reference voltage: IEVo is obtained from the specific band switching voltage in this example from the high channel band switching voltage, and this is used to clamp the control voltage supplied to the control voltage supply terminal 1a for tuning. Because it is a band, there is an advantage that it does not have any negative effect on the selection of other bands.

FIG. 5 shows another embodiment of the invention.

In this example of FIG. 5, npn is used instead of diode 8 in FIG.
In this case, a type transistor 8a is used.

That is, in FIG. 5, the movable element 6a of the variable resistor 6 is np.
The collector of this transistor 8a is connected to the base of an n-type transistor 8a, and the collector of this transistor 8a is connected to the high channel band switching voltage supply terminal 4h, and the emitter of this transistor 8a is connected to the electronic tuning tuner device 1 via a diode 10 for preventing reverse withstand voltage. It is connected to the control voltage supply terminal 1a for tuning.

The rest of the structure is the same as that shown in FIG.

Also in FIG. 5, the voltage supplied to the base of the transistor 8a is the control voltage obtained by the movable element 3a of the variable resistor 3, which is the lowest voltage V of the control voltages required for high channel band selection.

It is easy to understand that if the transistor 8a is selected to be conductive when the following conditions occur, the same effect as shown in FIG. 3 can be obtained.

It goes without saying that the present invention is not limited to the above-described embodiments, and that various other configurations may be adopted without departing from the gist of the present invention.

[Brief explanation of drawings]

FIG. 1 shows an example of a conventional multi-band electronic tuning tuner device; FIG. 2 and FIG. 4 are diagrams for explaining the present invention, and FIG. FIG. 5 is a block diagram showing one embodiment of the present invention. FIG. 5 shows the configuration of another embodiment of the present invention. 1 is an electronic tuning tuner device, 1a is a control voltage supply terminal for channel selection, 3 and 6 are variable resistors, respectively, 4h and 41 are band switching voltage supply terminals, and 8 is a diode.

Claims (1)

[Scope of utility model registration request] In an electronically tuned tuner device configured to be able to receive multiple bands, a reference voltage is formed from the specific band switching voltage, and the reference voltage is used to control the tuning control voltage supply terminal of the electronically tuned tuner device. A multi-band electronic tuning tuner device characterized by clamping a control voltage supplied to the tuner.