JPS5855712Y2 - channel display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for graphically displaying channels on a cathode ray tube in a television receiver.

In so-called electronic tuners, a variable capacitance diode is used as a tuning element and a channel selection voltage set by a variable resistor or the like is applied to the variable capacitance diode to select a channel. A means to display which channel is set is required.

For this reason, in the past, a voltmeter was provided to make this kind of display, and the magnitude of the channel selection voltage was indicated by the pointer of the voltmeter. In some cases, the size is limited, the display is difficult to understand, and the usability is poor.

In addition, there were devices that displayed graphics at different positions on the cathode ray tube screen depending on the selected channel, but this required a complicated display circuit and increased costs. Despite the use of a tuning voltage of a certain magnitude, the disadvantage is that it is difficult to change the channel of any band when displaying at the same position because only one color is displayed.

There were also devices that changed the display color of the channel display depending on the selected channel, but in that case, if the number of channels was large like a television receiver, the variety of display colors would increase accordingly. This has the disadvantage that the means for displaying the information becomes special and complicated, and it becomes difficult to understand.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an apparatus which can eliminate the above-mentioned drawbacks of the conventional apparatus, display channels in an easy-to-understand manner, and which can be implemented at low cost.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to drawings showing an embodiment of displaying set channels in an electronic tuner.

This device compares the magnitude of the channel selection voltage with the magnitude of the horizontal sawtooth wave voltage, generates an output when the two coincide, and applies it to the cathode ray tube, creating a vertical line that moves left and right across the screen. At the same time, the color of the display graphic is changed depending on the band to which the channel belongs, and correspondingly, the channel display characters of the same color as the display color are displayed on the cathode ray tube for each band. It is installed nearby.

In FIG. 1, reference numeral 1 denotes an electronic tuner comprising a UHF electronic tuner 4 and a VHF electronic tuner 5, both of which use variable capacitance diodes 2 and 3 as tuning elements, respectively. 5 is equipped with a switching diode 6 for switching between high and low levels of VHF, and also equipped with switching transistors 7 and 8 for switching power supply for switching between UHF and VHF reception.

9 is a channel selection voltage input terminal, 10 is a UHF switching voltage input terminal, 11 is a VHF low channel switching voltage input terminal, and 12 is a VHF high channel switching voltage input terminal.

Further, 13 is a channel selection circuit for generating a channel selection voltage and a switching voltage for the electronic tuner 1, and the channel selection voltage supplied to the variable capacitance diodes 2 and 3 is set to have a different magnitude depending on the channel. a variable resistor 14.15 for setting to generate the voltage, and a changeover switch 16.1 for generating the band switching voltage.
7 and a channel selection switch 18, 19 which is alternatively closed for channel selection.

These electronic tuner 1 and channel selection circuit 13
Channel selection and reception are performed by.

Furthermore, in the present invention, in order to compare this channel selection voltage with a horizontal sawtooth wave voltage and generate a vertical line on the cathode ray tube at a position corresponding to the magnitude of the channel selection voltage,
Level conversion circuit 20 and horizontal sawtooth voltage generation circuit 21
, a voltage comparison circuit 22 , a waveform shaping circuit 23 , and a gate circuit 24 .

A detailed configuration example of each circuit is shown in FIG.

In the horizontal sawtooth voltage generation circuit 21, the horizontal pulse as shown in FIG. 3A applied to the horizontal pulse input terminal 25 is inverted by the transistor 26, and then
8 and a capacitor 29 to generate a horizontal sawtooth wave voltage as shown in FIG.
2 to the base of one of the transistors 30.

On the other hand, in the level conversion circuit 20, the channel selection voltage applied to the channel selection voltage input terminal 31 is appropriately level-converted using a transistor 32 and a resistor 33, and is converted to an intermediate level of the horizontal sawtooth wave voltage B as shown in FIG. , to the base of the other transistor 34 of the voltage comparison circuit 22.

As a result, as shown in the figure, the collector of the transistor 30 of the voltage comparator circuit 22 receives a horizontal sawtooth wave voltage at a high level when the channel selection voltage (after conversion) C is larger than B; A comparison output that is sometimes low level is generated.

Therefore, this comparison output is connected to capacitor 35 and resistor 36.
, 37, and a transistor 39 takes out only the differential output of negative polarity, inverts it, and shapes the waveform. As shown in FIG. (2) It is possible to obtain a matching output that occurs when the size of C and C exactly match.

The timing at which this coincidence output E is generated changes back and forth in accordance with the change in the magnitude of the channel selection voltage (after conversion) C as shown by the broken line and the dashed-dotted line in the figure.

Therefore, if this coincidence output E is added to the video amplifying circuit 40 or the reproducing circuit 41, the cathode ray tube 42 will be connected as shown in FIG.
Vertical line 4 that moves horizontally on the screen for channel display
3 can be displayed, and its horizontal position is determined by the magnitude of the channel selection voltage, so there is a scale 44.45 around the cathode ray tube 42 that shows the channel number according to the position of the vertical line 43. By providing .46, the selected channel can be displayed very clearly.

Furthermore, since the overlapping voltage portion is used as the tuning voltage for each band, the vertical line for display may be displayed in the same position for each band, so this channel display may be displayed in a different color for each band. indicate.

For this purpose, a gate circuit 24 is provided, and this gate circuit 2
4 is provided with □ AND games) 47, 48, and 49, and one for VHF low channel and one for VHF low channel, respectively.
The switching voltage for the HF channel and the UHF channel and the coincidence output E from the waveform shaping circuit 23 are applied, and the AN
The outputs of the D gates 47, 48, and 49 are applied to the red, green, and blue color reproduction circuits of the color reproduction circuit 41, respectively.

In the illustrated case, they are applied to the bases of red, green, and blue color output transistors 50, 51, and 52, respectively.

Therefore, the vertical line 42 for channel display is red for the VHF HF channel, green for the VHF high channel, and green for the VHF high channel.
Since the channels are displayed in blue, it is possible to see at a glance which band's channel is being selected.

At this time, the display colors of the scales 44, 45, and 46 are also made to correspond to the display colors of the vertical lines 42 by changing them to red, green, and blue so that they match for easy understanding.

In the above embodiment, an example was explained in which the shape of the shape of the channel display is a vertical line, but it may be any shape such as a horizontal line or a small dot, and the tuning voltage can be set using a sawtooth wave voltage with a horizontal or vertical period. Any device that compares and moves in accordance with the magnitude of the channel selection voltage may be used.

As described in detail above, according to the present invention, channels can be displayed in an easy-to-understand manner using graphics on a cathode ray tube.

In addition, in order to display the figure, the tuning voltage and the horizontal and vertical periodic sawtooth waves are compared and the point where the two coincide is displayed, so the circuit configuration can be simplified. and can be obtained at low cost.

Furthermore, when using an electronic tuner, the same voltage may be used in each band, and the displayed figures will be displayed in the same position, but in this invention, each band is displayed in a different color. Similarly, the channel letters are also colored in different colors, so there is no fear of misunderstanding the channel, and the system is easy to use.

Moreover, although there are many channels in a television receiver, there are only about three bands, so the number of display colors can be about three, and the display can be clearly distinguished.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a channel display device according to an embodiment of the present invention, Fig. 2 is a more detailed circuit diagram of the main parts of the device, and Figs. 3 A, B, C, D, E, and F are the same. FIG. 4 is a waveform chart for explaining the operation of the device, and a front view showing the display mode of the device. 1... Electronic tuner, 2... Variable capacitance diode, 4... Electronic tuner for UHF, 5
...VHF electronic tuner, 9...Channel selection voltage input terminal, 10...UHF switching voltage input terminal, 11...VHFHF multi-channel switching voltage Input terminal 2...VHFHF multi-channel switching voltage input terminal 2...Channel selection circuit, 14.15...Variable resistor, 16
．． 17... Band switching switch, 18.19
...Channel selection switch, 21...
・Horizontal sawtooth wave voltage input terminal, 22... Voltage comparison circuit, 23... Waveform shaping circuit, 24...
... Gate circuit, 26 ... Horizontal pulse input terminal, 40 ... Video amplification circuit, 41 ... Color reproduction circuit, 42 ... Cathode ray tube, 43・・・・・・
・Vertical lines for channel display, 44, 45, 46...
...Scale, 47.48.49...AND gate, 50...Red color output transistor, 5
1...Green color output transistor, 52...
...Blue color output transistor.

Claims (1)

[Scope of utility model registration request] A voltage generation circuit that generates a channel selection voltage having a different magnitude for each channel according to the selected channel and selects the channel in addition to the variable capacitance diode of the electronic tuner, and a voltage generation circuit that selects the channel selection voltage. a voltage comparator circuit that compares the magnitude with a horizontal or vertical periodic sawtooth wave voltage, and a matching output obtained from the voltage comparator when the magnitude of the channel selection voltage matches the sawtooth voltage. a display circuit that projects channel display graphics at different positions on the cathode ray tube screen;
For each band of the channel, the above-mentioned matching output is added to a different color circuit in the color reproduction circuit, and a gate circuit that projects the above-mentioned channel display figure in a different color for each band, and a gate circuit for each band around the cathode ray tube. and channel display characters provided at different positions, wherein the channel display characters are provided in the same color as the projection color of the channel display graphic for each band.