JPS6234173B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a channel selection device for a television receiver, and more particularly to a preset means that can variably preset the correspondence between a channel selection switch and channels that can be received by operating the switch. The present invention relates to a circuit connection that makes it possible to reduce the number of preset control switches that output preset mode signals in a channel selection device equipped with a preset mode signal. FIG. 1 is a circuit diagram showing main circuits in a conventional channel selection device. In the figure, 1 to 4 are preset control switches (self-resetting type) that control the preset mode;
5 to 6 are diodes for blocking reverse current, 8 to 10 are input terminals to the tuning LSI 16 for controlling presets, and 11 is a channel selection terminal for channel selection.
Input terminals to the LSI 16; 12 is a group of position output terminals from the LSI 16; 13 is a group of tuning switches for transmitting the output of the position output terminal group 12 to the input terminal 11; 14 is an override of preset control switches 1 to 4. Power supply protection resistor, 15 is input terminal 1
1 is a bias resistor, 16 is a tuning LSI having terminals 8 to 12, and 17 is a power supply terminal.
Reference numeral 7 is a changeover switch, which enables the operation of the channel selection switch 13 and preset control switches 1 to 4 when the switch is switched in the direction a (as shown), but when it is switched in the direction b. Since the circuit is cut off, the operation of each of the above-mentioned switches is disabled thereafter. The tuning LSI 16 selects in multiple preset modes by combining input signals to input terminals 8 to 10.
It is a circuit element that can preset the correspondence between the channel selection switch group 13 and the reception channel, and also has a position output terminal group 12 connected to the input terminal 11.
By transmitting one output of the channel selection switch group 13 through one switch of the channel selection switch group 13, the corresponding channel output is received. Next, the operation of the circuit shown in FIG. 1 will be explained. In FIG. 1, each switch in the channel selection switch group 13 is configured such that, for example, the first switch is for NHK channel 1,
The switches are preset to correspond to the receiving channels, such as the third channel, etc. Then, when any switch in the channel switch group 13 is pressed, the level of the voltage applied from the power supply terminal 17 to the input terminal 11 via the resistor 15 becomes
It changes depending on which switch in switch group 13 is pressed, and then LSI 1
6, an arithmetic circuit (not shown) operates to find the pressed switch in the switch group 13 from among the position output terminal group 12, and lights up a lamp (not shown) corresponding to the switch. etc., to indicate that the channel corresponding to the switch is receiving data. Furthermore, depending on which of the preset control switches 1 to 4 is pressed, the correspondence between the channel selection switch group 13 and the reception channels can be changed in the preset mode as shown in the following table.

[Table] The above table will be explained. Now, in FIG. 1, if the preset control switch 1 is pressed down, only 8 of the input terminals 8 to 10 of the channel selection LSI 16 will go to H (high) level due to the voltage from the power supply terminal 17, as shown in the table. and the other terminals are L
(low) level, and at this time, the
The preset mode in the LSI 16 is a forward search mode. That is, before pressing the preset control switch 1, the channel selection switch group 1
The first channel selection switch in 3 is NHK 1st.
If the control switch 1 is operated once, the first channel selection switch becomes compatible with NHK channel 3, and when the control switch 1 is operated again, the first selection switch becomes compatible. The station switch becomes compatible with the next 4th channel. In this way, by operating the preset control switch 1, it is possible to preset by switching the correspondence between the channel selection switch and the reception channel in the forward direction of increasing frequency. Similarly, when the preset control switch 2 is pressed down, input terminals 8 and 10 go to H level due to the voltage from power supply terminal 17, terminal 9 goes to L level, and the preset mode becomes reverse search mode. In other words, the correspondence between the tuning switch and the reception channel is determined for each operation of the control switch 2.
For example, it is possible to preset by switching from the 12th channel to the 11th channel, and then to the 10th channel in the opposite direction where the frequency decreases. Also, if you press preset control switch 3,
Input terminal 9 becomes H level, and at this time, the channel selection
The preset mode in the LSI 16 is the fine adjustment mode (high). That is, if the control switch 3 is kept pressed, the correspondence between the channel selection switch and the channel frequency gradually shifts toward higher frequencies. Similarly, if you keep pressing the control switch 4,
The mode is set to fine tuning mode (low), and the correspondence between the tuning switch and the channel frequency gradually shifts toward lower frequencies. The tuning LSI 16 that performs the circuit operation described above is
Since it is not directly related to this invention, its detailed configuration will not be explained any further. Now, the conventional channel selection device as described with reference to FIG. 1 has the disadvantage that the number of preset control switches is large, resulting in high cost. The present invention was made in order to solve the drawbacks of such conventional devices, and an object of the present invention is to provide a channel selection device that requires fewer preset control switches than the conventional device and is therefore inexpensive. Our goal is to provide the following. The main points of the configuration of the present invention are a plurality of tuning switches for selecting reception channels, a presetting means for variably presetting the correspondence between each tuning switch and the reception channel, and a presetting means for presetting the correspondence relationship between each tuning switch and the reception channel. A channel selection device for a television receiver comprising a preset control switch for outputting a mode signal, and a first changeover switch for enabling or disabling operation of the channel selection switch. A second changeover switch is provided which operates in conjunction with the preset control switch, and the preset mode signal is output by a series combination of the operation of the preset control switch and the changeover operation of the second changeover switch. The point is that the number of points can be reduced from the number of preset mode signals. Next, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 is a circuit diagram showing one embodiment of the present invention. In the figure, 1 and 2 are preset control switches (self-resetting type), 19 is a diode for reverse current prevention, and 18 is a changeover switch for two circuits, which connects terminals a-2, c-2, and b-2. and a second switch including terminals a-1, c-1, and b-1. Other codes 8, 9, 10, 11, 12, 13, 14,
15, 16 and 17 refer to the same items as in FIG. Now, one end of the preset control switches 1 and 2 is
It is connected to one end of a resistor 14, and the other end of the resistor 14 is connected to a power supply terminal 17. The other end of the preset control switch 1 is connected to the cathode of the diode 19 and the first midpoint c-1 of the changeover switch 18, and the anode of the diode 19 is connected to the other end of the preset control switch 2 and the input terminal 10. . The a-side terminal a-1 of the changeover switch 18 is connected to the input terminal 8, and the b-side terminal b-1 is connected to the input terminal 9. In addition, the a-2 terminal of the selector switch 18 is open,
The second midpoint c-2 is connected to the output terminal group 12 through the switch group 13, and the b-2 terminal is connected to the input terminal 11.
is connected to one end of a resistor 15, and the other end of the resistor 15 is connected to a power supply terminal 17. According to this embodiment, the input terminals that can be controlled by the preset control switches 1 and 2 can be changed depending on whether the changeover switch 18 is connected to the a side or the b side. Control of four types of preset modes is possible using two preset control switches.

[Table] A description of the table will be omitted since it is thought to be clear from the above description of the table.
However, to explain a little about the changeover switch 18,
When the first changeover switch of this switch 18 is switched to the a side, the terminals c-2 and b-2 are turned off, so the channel selection input terminal 11 from the channel selection switch group 13 is turned off. This is a switch that can cut off the circuit leading to the channel and disable subsequent channel selection operations (channel switching caused by mischief by children or the like while viewing a specific channel). As described above, according to the present invention, the number of switches for preset control can be reduced by connecting a preset control switch and another switch that is linked to a changeover switch that can subsequently stop the channel selection operation. This has the advantage that it is possible to provide an inexpensive channel selection device that can perform the same functions while requiring fewer devices than conventional ones.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing essential circuits in a conventional channel selection device, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. In the figure, 1 to 4 are preset control switches, 5 to 6 are reverse current blocking diodes, 7 is a changeover switch, 8 to 10 are input terminals for preset control, 11 is an input terminal for channel selection, and 12 is a position output. Terminal group, 13 is tuning switch group, 1
4 is a resistor for overpower protection, 15 is a bias resistor, 16 is a channel selection LSI, 17 is a power supply terminal, 18 is a changeover switch for two circuits, and 19 is a diode for preventing reverse current.

Claims (1)

[Claims] 1. A plurality of tuning switches for selecting reception channels, a preset means for variably presetting the correspondence between each tuning switch and the reception channel, and a preset control for outputting a preset mode signal to the preset means. A channel selection device for a television receiver comprising a switch and a first switch for enabling or disabling the operation of the channel selection switch. A changeover switch is provided, and the preset mode signal is output by a series combination of the operation of the preset control switch and the changeover operation of the second changeover switch. A channel selection device for a television receiver, characterized in that the channel selection device can be subtracted from the score of the television receiver.