JPS6052175A - Tuning display device - Google Patents

Abstract

PURPOSE:To judge correctly the turning state by displaying a character, a pattern and its background on a CRT with a different color and changing the color of the background in response to the tuning state. CONSTITUTION:A green character 54 and a background 55 surrounding it in red are displayed on the CRT30 based on an output of a character generator 32. Further, a signal corresponding to the degree of tuning produced based on a video intermediate frequency signal (a) is applied to a comparator 47, and its output and an output voltage (k) from an AND gate 20 displays a part of the background 55 as a black background 55'. Since the width of the background 55' is proportional to the pusle width of the output voltage (k), the black width is decreased as the tuning approaches the optimum tuning. Thus, the complete red background 55 without black part is obtained at the optimum tuning state. Thus, the tuning state is judged correctly. Even if a graph is displayed in place of the character, similar effect is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a tuning display device for displaying a tuning state on the screen of a cathode ray tube of a color television receiver.

(Structure of a conventional example and its problems) A tuning display device in a conventional color television receiver was constructed as shown in FIG.

In FIG. 1, a video intermediate frequency signal a is supplied to one end of a capacitor 1, and bias setting resistors 2 and 3 and the pace of a carrier amplification transistor 4 are connected to the other end. The emitter of the carrier wave amplification transistor 4 is grounded, and the collector is connected to the power source B via a coil 5 and a capacitor 6 that are connected in parallel. The anode of the rectifier diode 7 is connected to the center tap of the filter 5, and its cathode is connected to the other end of the smoothing capacitor 8 whose one end is grounded, and then connected to the transistor 100 through the resistor 9. It is connected to the. The emitter of transistor 10 is resistor 11
The collector is connected to the power source B via a resistor 13 and to the plus input terminal of a comparator 14 . Note that the transistor 10
The emitter and collector of are connected to each other via a resistor 15. On the other hand, sawtooth wave generation transistor 16
A positive horizontal flyball motherboard B is supplied through a resistor 17, its emitter is grounded, and its collector is connected to the power source B through a resistor 18, and a capacitor 19. is grounded via the positive input terminal of the comparator 12 and the comparator 14.
It is connected to the negative input terminal of the The output terminals of the comparators 12 and 14 are respectively connected to the input terminals of the AND GO 20. In addition, the green cathode drive transistor 21, the red cant drive transistor 22, and the blue cant drive transistor 23 are supplied with green, red, and blue imaging +Fie+d and e, respectively, for each pace. The emitters of each are grounded through resistors 24, 25 and 26, respectively, and the collectors of each are connected to power supply element B through resistors 27, 28 and 29, respectively. connected to the cathode, red cathode and blue cathode respectively. The output terminal of the AND gate 20 is connected to the base of the green cathode driving transistor 21 via the diode 31.

Next, the operation of this embodiment will be explained. The video intermediate frequency signal a applied to one end of the capacitor l is amplified by the carrier wave amplifying transistor 2, and is converted into the video intermediate frequency signal a.
The carrier wave component is extracted by the filter 5 and the capacitor 6, which are selected to resonate at the frequency of the ν transmitted wave component,
The rectifying diode 7 and the smoothing capacitor 8 detect the wave and take it out as a DC voltage, and the voltage is highest at the optimum tuning point. When this DC voltage is applied to the pace of transistor 10 via resistor 9,
The emitter voltage f of the transistor 10 increases as the pace voltage increases, and the collector voltage g decreases as the base voltage increases. On the other hand, the horizontal flyback pulse b applied to one end of the resistor 17 is converted into a sawtooth wave voltage by the sawtooth wave generating transistor 16, the resistor 18, and the capacitor 19. And comparator 1
The emitter voltage f of the transistor 10 is input to the negative input terminal of 2, and the sawtooth wave voltage f is input to the positive input terminal.
In addition, the collector voltage of the transistor IO is input to the positive input terminal of the comparator 14, and the sawtooth wave voltage is input to the negative input terminal of the comparator 14. Output voltages l and j are output. Further, these output voltages i and j are inputted to an AND gate 20, and a pulsed output voltage k as shown in FIG. 2 is outputted from the AND gate 20. As is clear from FIG. 2, as the tuning state approaches the optimum tuning point, the emitter voltage f of the transistor 10 increases.
When it goes up, it goes up, and when the collector voltage g goes down, it goes up and down)2
The pulse width for the output voltage of 0 becomes narrower. in this way,
i depending on the entrainment state? AND gate 2 with variable loop width
An output voltage k of 0 is supplied to the pace of the green cathode drive transistor 21 via the diode 31,
The signal is mixed with the green video signal and input to the cathode ray tube 30.

Here, since the output voltage of the AND gate 20 is a pulse signal synchronized with horizontal scanning, the television broadcast image is displayed on the screen of the cathode ray tube 30 as a vertical green band with a width corresponding to the pulse width. It is photographed with Therefore, the width of this green band changes depending on the tuning state, and becomes the narrowest at the optimum tuning point.

However, in the above conventional example, depending on the television broadcast image projected on both sides, the green band may be difficult to see.
, it was difficult to judge the width of the green band, and the user could not judge whether the tuning condition was optimal just by looking at the green band on the screen, and color television receivers It was not possible to clearly know the tuning state unless you operated the adjustment knob to change the tuning state and change the width of the green band. Therefore, even though the tuning state is optimal, the user has to operate the adjustment knob to remove the tuning state from the optimal tuning point and then adjust it to the optimal tuning point again, which is a wasteful operation. I was going.

(Object of the invention) The present invention has been made in view of the drawbacks of the above-mentioned conventional examples, and
To provide a tuning display device in which the display on the screen is easy to see and it is possible to judge whether or not the tuning state is optimal just by looking at the screen.

(Structure of the Invention) In order to achieve the above object, the present invention displays characters or figures and their backgrounds in different colors on the screen of a cathode ray tube of a color television receiver, and The carrier component is extracted, amplified, and detected, and the color of the background is partially changed depending on the tuning state. When the tuning state is optimal, the background is displayed in its entirety, and when it is not optimal, the background color is displayed in its entirety. is displayed in an incomplete form.

(Explanation of Examples) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a diagram showing the configuration of an embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same components. Also the third
In the figure, numeral 32 denotes a character generator, to which a control microcomputer 33 is connected, horizontal flyback pulses b and vertical pulses L are input, and positive polarity pulses for displaying characters. A character output terminal 34 outputs a character output signal, and a positive polarity terminal 34 outputs a character output signal of
and a background output terminal 35 for outputting a background output signal in the form of a background signal. This character generator 320 character output terminal 3
4 is connected to another green cathode drive transistor 370 whose emitter and collector are shared with the green cathode drive transistor 21 through a resistor 36, and the background output terminal 35 is connected to the emitter through a resistor 38. is connected to the base of the grounded video signal blanking transistor 39, and the resistor 40
After that, the collector of a background output control transistor 41 whose emitter is grounded and whose conductor is connected to the output terminal of the AND cable 1/20 via a resistor 40, and a red cathode drive transistor 22 are connected. and the base of another red cathode drive transistor 42 having a common emitter and collector.

The collector of the video signal blanking transistor 39 is connected to a diode 44. whose anodes are connected to the bases of green, red, and blue cathode drive transistors 21, 22, and 23, respectively. , 45
and 46 cathodes are commonly connected.

Further, the converter 47 for determining the optimum tuning point has its positive input terminal connected to the cathode of the diode 7, and its negative input terminal connected to a variable resistor 48 for setting the reference voltage.
is connected to the center terminal of the This variable resistor 48
One end is connected to the power supply 1B via a resistor 49, and the other end is grounded via a resistor 50. The output terminal of the converter 47 is connected via a resistor 51 to the base of a switching transistor 52 whose emitter is grounded. Note that the switching transistor 52
The collector of is connected to the base of the background output control transistor 42.

Next, the operation of this embodiment will be explained. Is the character generator 32 in the microcomputer 33? Ilj, the fourth
As shown in the figure, for example, characters 54 such as r JtrST J and a background 55 surrounding the characters 54 are displayed at a predetermined position on the screen 53'' of the cathode ray tube 30 on which the television broadcast image is projected. As shown, a character output signal and a back claw output signal are outputted from the character output terminal 34 and the background output terminal 35, respectively. Here, the horizontal flyback gurusu b and vertical flyback gurusu l inputted to the character generator 32 are used when setting the display positions of the characters 54 and the background 55. This character output terminal 34 power 1
1] The input character output signal drives the green cathode drive transistor 37 via the resistor 36,
As shown in Fig. 4, the green letters 5 of “JUST” appear on the screen 53.
Display 4. Further, the background output signal outputted from the background output terminal 35 drives the red cathode drive transistor 43 through the resistor 40f, and as shown in FIG. is displayed in red, and the video signal blanking transistor 39 is made conductive via the resistor 38. At this time, the comparator 47 for determining the optimal tuning point has its negative input terminal supplied with the reference voltage set by the variable resistor 48, and its positive input terminal receives the carrier wave component from the video intermediate frequency signal from the diode 7. A signal corresponding to the tuning degree is extracted, amplified and detected, and this reference voltage is set so that the output is high at the optimum tuning point.Therefore, if the tuning state is not optimal, , the comparator 47 outputs a low level and the switching transistor 52 is cut off, so the background output control transistor 42 repeatedly turns on and off due to the A pulse-like output voltage k from the AND gate 20. The background output signal is cut off only while a pulse is being output to the output voltage of the AND gate 20, and a part of the red background 55 is changed to a black background 55' as shown in FIG. 4.This black color is displayed. The width of the background 55' is AND gate 20
Since it is proportional to the pulse width of the output voltage, it becomes wider if the tuning state is far from the optimum tuning point, and narrows as it approaches the optimum tuning point. Note that the width of the red background 55 is set so that even when the width of the black background 55' becomes the widest, it does not exceed the width of the red background 55.

When the optimum tuning point is reached, the controller for determining the optimum tuning point...? The output of the regulator 47 becomes high, making the switching transistor 52 conductive and cutting off the background output control transistor 42. Therefore, the red cathode drive transistor 43 is driven by the background output signal supplied without being cut off from the background output terminal 35 of the character generator 32, and as shown in FIG. A full red background 55 is displayed. ' In this way, when the tuning state is not optimal, a part of the red background 55 is changed to a black background 55' with a width corresponding to the tuning degree, and when the optimal tuning point is reached, the red background 55 is displayed. Since the background 55 is displayed in its entirety, the user can correctly judge the tuning state just by looking at the display.

In the above embodiment, the characters and their backgrounds are used for display, but it is also possible to display a figure on the edge of the character and to display the state of synchronization by the figure and its background.

(Effects of the Invention) As explained above, the present invention displays characters or figures and their backgrounds in different colors on the screen of a cathode ray tube, and extracts the carrier wave component from the video intermediate frequency signal 'fe,...! ll
By using the output, amplified and detected signal, the background color is partially changed with a width depending on the tuning state, and when the tuning state is outside the optimal state, the background color is unified and displayed in one color. The display is easy to see due to the contrast between the letters or figures and the surrounding background of different colors, and the user can accurately judge the state of synchronization just by looking at the display. Furthermore, trademarks, company names, etc. are displayed as text. By doing so, it has the effect of becoming counter-propaganda.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a conventional tuning display device, FIG. 2 is a signal waveform diagram of the main part of FIG. 1, FIG. 3 is a circuit diagram of an embodiment of the present invention, and FIG. FIG. 5 is a diagram showing a display state of the screen when the tuning state is not optimal in an embodiment of the present invention, and FIG. 5 is a diagram showing the display when the tuning state of FIG. 4 is optimal. 4... Transistor for carrier wave amplification, 7... Diode for rectification, 12, ], 4, 47... Transistor for sawtooth wave generation, 20
...And Gate, 21.37...Aneiro Ka-1"
)" Live transistor, 22, 713... Clear one-color cathode drive transistor, 30... Cathode ray tube, 32... Character generator, 33... Microcontroller Lo...-ta, 34
...Character output terminal, 35...Background output signal, 39.
・L transistor for video signal blanking, 42...
・Background 1" Power control transistor, 52...Switching transistor, 54...Character, 55+55
'・Back immediately. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] Means for displaying characters or figures and their background in different colors on the screen of a cathode ray tube of a color television receiver; and Tuning detection means for extracting, amplifying and detecting a carrier wave component from a video intermediate frequency signal. and means for changing the color of the background of the character or figure in accordance with the output of the synchronization degree detection means and the synchronization state.