JPS62271567A - Television receiver - Google Patents

Abstract

PURPOSE:To eliminate such a drawback that a on screen is displayed although no picture is projected by blocking a horizontal pulse supplied to a character generator at the time of selecting a channel. CONSTITUTION:When a channel CH is selected, a mute pulse M is impressed on the base of a transistor TR1 in a switch circuit 7 from a station selection circuit 1. Since the transistor TR1 is turned on only when the CH is switched and no horizontal pulse H is impressed, on screen output signals such as characters and graphics from the character generator circuit 3 are not outputted. Simultaneously a video field circuit 6 controls a video signal and erases it. Thus such a drawback that on screen is displayed although a picture is not projected on a CRT5 and gives mistaken recognition can be eliminated.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a television receiver capable of on-screen display of channel numbers, volume, etc. on a cathode ray tube (CRT) screen.

2. Description of the Related Art FIG. 2 shows a conventional example of a television receiver that can display on-screen information such as channel number, volume, type of external input, etc. on a CRT screen.

In the figure, 1 is a channel selection circuit, 2 is a video circuit, and 3 is a character generator circuit, all of which are integrated circuits. 4 is a video, on-screen drive circuit, 5 is a CRT, and 6 (d) is a video defeat circuit.

Conventionally, when selecting a channel, the video defeat circuit 6, which eliminates noise signals, momentarily defeats the GET screen to erase the video component, but at this time, the character generator circuit 3 eliminates on-screen characters and figures Displayed on the CRT screen.

Problems to be Solved by the Invention However, with conventional means, when selecting a channel, the video component is erased and the screen becomes pitch black, but on-screen characters and figures are displayed on the CRT screen, causing trouble to the user. There was a problem in that it gave the misunderstanding that the company was not doing the same thing.

The present invention solves these conventional problems37,-
7, which erases the on-screen image at the same time as the video component when selecting a channel, and provides a television receiver that eliminates the drawback of displaying the on-screen image even when no image is displayed.

Means for Solving the Problems The television receiver of the present invention has horizontal pulses supplied to the character generator circuit so that the on-screen is not displayed on the CR7 screen when selecting a channel.
A switch circuit is inserted into one of the supply paths with fewer vertical pulses, and the switch circuit is operated by a mute pulse generated when selecting a channel, thereby cutting off the supply of the pulses.

Function: The television receiver of the present invention has a switch circuit inserted into the supply path for at least one of horizontal pulses and vertical pulses to the character generator circuit, and operates the switch circuit to supply the pulses when selecting a channel. By shutting off the character generator output and opening the character generator output, the disadvantage of displaying an on-screen image even when no image is displayed can be completely eliminated.

EXAMPLE An example of the present invention will be described below. Components in the drawings that are the same as those in FIG. 2 will be described with the same reference numerals. In FIG. 1, a switch circuit 7 is composed of a transistor TR1 and a resistor R1, and a mute pulse M generated during channel selection is applied to the base side of the transistor TR1 via the resistor R1. Further, an inverted horizontal pulse H necessary for outputting the character generator circuit 3 is applied to the collector of the transistor TR1. Resistors R2 and R3 are dividing resistors for reducing the level of the horizontal pulse H. The horizontal pulse H controls the horizontal position on the CR7 screen when displaying on-screen characters and figures on the screen.If this horizontal pulse H is not input to the character generator circuit 3, the on-screen output signal will not be output. No output.

6.

Now, when a channel is selected, a mute pulse M is applied from the channel selection circuit 1 to the base 2 of the transistor TR1 via the resistor R1, and only when the channel is switched, the transistor TR1 is turned on and dropped to the horizontal pulse Hi ground.

Therefore, the horizontal pulse H is not applied to the character generator circuit 3, and no on-screen output signal is output.

At the same time, the video signal is controlled by the video defeat circuit 6, and the video signal is also erased.

Note that the vertical position of on-screen characters and figures on the CR7 screen is determined by vertical pulses, so even if the vertical pulses are not applied to the character generator circuit 3 instead of the horizontal pulses, the above embodiment will not work. A similar effect can be obtained. Of course, the supply of horizontal and vertical image pulses may be stopped.

Effects of the Invention As described above, the television receiver of the present invention erases the video signal when selecting a channel and also erases the on-screen output at the same time. Therefore, it is possible to provide a television receiver that eliminates the drawback of giving a false impression.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a television receiver according to an embodiment of the present invention, and Fig. 2 is a circuit diagram of a conventional example.・Video circuit,
3...Character generator circuit, 4.
·····video. On-screen drive circuit, 6...CRT,
e...Video defeat circuit, 7...
・Switch circuit 0

Claims (1)

[Claims] A character generator circuit for displaying on-screen characters and figures on the cathode ray tube screen is provided, and a switch circuit is inserted in the supply path for at least one of the horizontal pulses and vertical pulses supplied to the character generator circuit to select a channel. The television receiver is configured to apply a mute pulse generated at the time to the switch circuit to operate the switch circuit and cut off the supply of the pulse.