KR960005938B1 - TV operating mode switching device with or without line signal - Google Patents

Abstract

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Description

TV operating mode switching device with or without line signal

1 is a diagram showing a configuration for switching the operation mode of a TV according to the prior art.

2 is a block diagram of an operation mode switching apparatus of a TV constructed according to an embodiment of the present invention.

3 is a flowchart for briefly explaining the operation of the apparatus shown in FIG.

* Explanation of symbols for main parts of the drawings

10,50: VCR section 12,52: video circuit

20,100: TV unit 22,78: tuner / IF module

26,56: image processing unit 56: image signal detection circuit

58: data generator 72: low pass filter

74: high par filter 76: data detector

80: first signal detector 82: second signal detector

92: CRT

The present invention relates to an apparatus suitable for switching various operation modes of a television (hereinafter referred to as a TV) to interlock with an output signal of a VCR when a video signal is output from a video cassette recorder (hereinafter referred to as a VCR).

1 shows a connection relationship between a general VCR unit 10 and a TV unit 20. As shown in FIG.

In the VCR unit 10, the line signal from the video circuit 12 through the A / V line 9 and the RF signal output from the antenna 5 through the RF line 7 from the antenna 5 through the modulation unit 14 are transmitted to the TV unit. Provided by 20.

In the TV unit 20, the RF signal is transmitted to the switch 24 via the tuner / IF module 22 and the A / V line signal is directly transmitted to the switch 24. When the user selects a desired signal, the control switch 24 is controlled by the microcomputer 30, so that only the signal selected by the user is passed through the image processor 26 by the driver 28 and the CRT ( 32).

This process should be determined by the user to switch the channel mode of the tuner / IF module 22 of the TV unit 20 to channel 3 or channel 4 for the signal output of the VCR unit 10, In addition, there was an inconvenience caused by a very cumbersome operation of switching the mode of the switching switch 24 to the input mode of the A / V line signal or the RF signal.

Therefore, the operation of the present invention, depending on the presence or absence of a signal transmitted from the VCR to the TV via the A / V line when the VCR is operated, the TV processes the A / V line signal or the RF line signal. In order to provide a television operation mode switching device with or without a line signal, the operation mode of the TV is automatically adjusted, specifically, a switch and a tuner of the TV.

Hereinafter, the present invention will be described as one embodiment with reference to the accompanying drawings.

2 shows a block diagram of a TV mode automatic switching device constructed in accordance with the present invention.

The VCR unit 50 includes a video circuit 52 for processing a video signal, a modulator 54 for RF modulating a broadcast signal input from the antenna 5 and an output of the video circuit 52, and a signal synthesis circuit ( 65). The signal synthesizing circuit 65 is connected to a video signal detecting circuit 56 for detecting the presence or absence of a video signal from the video signal output from the video circuit 52, and a video signal detecting circuit 56 to detect the presence of the video signal. A data generator 58 for generating data to be represented, and an adder 60 for adding the output from the data generator 58 to the output of the modulator 54.

On the other hand, the TV unit 100 is connected to the low pass filter (LPF: 72) and high pass filter (HPF: 74) and the output of the low pass filter 72, respectively connected to the RF signal output from the adder (60) A connected data detector 76, a tuner / IF module 78 connected to the output of the high pass filter 74, a TV broadcast signal from the tuner / IF module 78 and a video circuit of the VCR unit 50; A switch unit 84 for selectively switching the A / V line image signal output from the 52, an image processing unit 86 for processing the image signal transmitted from the switch unit 84, and the image A CRT 92 for displaying an image signal processed by the processor 86, a first signal detector 80 for determining the presence or absence of an A / V line image signal from the VTR unit 50, and the tuner / IF module A second signal detector (82) for determining the presence or absence of a TV video signal from the output of (78), the tuner / IF module and the C; A microcomputer 90 that controls the driver circuit 88 for driving the RT 92 and controls the switch unit 84 in response to signals detected from the first and second signal detectors 80 and 82, respectively. It includes. In addition, a power supply unit (not shown) for providing ever power and ON / OFF power required for the microcomputer 90 and the like.

The operation of the TV mode automatic switching device having the above-described configuration will be described below.

The video signal detection circuit 56 is activated in accordance with the output of the video circuit 52 of the VTR section 50. That is, when an image signal is output from the video circuit 52, the image signal detection circuit 56 outputs a high level signal, and conversely, if no image signal is provided from the video circuit 52, the image signal detection circuit 56 Outputs a low level signal. The output signal from the video signal detection circuit 56 is used as a signal to excite the data generator 58.

The data generator 58 receives a high level signal indicating that an image signal exists from the image signal detection circuit 56 and outputs a pulse of a specific frequency of several tens of KHZ. This data generator 58 may be implemented with a low frequency pulse generator. When a low level signal is output from the image signal detection circuit 56, the data generator 58 remains in an off state where no signal is generated. The output from the data generator 58 is provided as one input of the adder 60, which is provided from the video circuit 52 and the antenna 5 as another input and modulated via the modulator 54. Receive The adder 60 adds these two signals to output the TV unit 100. In this case, the adder 60 may add frequencies of several tens of KHZ generated from the data generator 58 when an image signal is output from the video circuit 52. Thus, outputting a frequency greater than the basic RF signal passed through modulator 54 may mean that A / V line signal is output from video circuit 52. However, it means that no video signal is generated from the video circuit 52 when only pure RF modulation frequency is output from the adder 60.

In the TV unit 100, the A / V input signal of the VCR unit 50 is provided to the first signal detection unit 80. Like the video signal detection circuit 56 of the VCR unit 50, the first signal detector 80 determines whether an A / V input signal is present and outputs the determined result to the microcomputer 90. On the other hand, the RF modulated signal output from the adder 60 of the VCR unit 50 passes through the low pass filter 72 and the high pass filter 74 of the TV unit 100, the low pass filter 72 Passing through the low frequency band of the output from the adder 60 causes the next stage of the data detector 76 to detect the tens of KHZ frequency components generated by the data generator 58 of the VCR section 50. At this time, the signal detected by the data detector 76 is output to the microcomputer 90. The high pass filter 74 removes the signal detection data of the low frequency components accompanying the RF modulated signal and outputs only the pure RF modulated signal to the next stage tuner / IF module 78.

The tuner / IF module 78 receives the RF modulated signal and demodulates the video signal from the signal. The IF demodulated signal by the tuner / IF module 78 is input to the second signal detector 82, and the second signal detector 82 determines whether there is an IF demodulated signal and provides the determined result to the microcomputer 90. do.

In the microcomputer 90, when the detection signal from the first signal detection unit 80 is at a high level indicating the presence of the A / V signal, the power supply unit turns on the power and the switch unit 84 transmits the A / V line signal. Outputs a control signal for switching to line mode for. However, when the detection signal from the second signal detection unit 82 is output as a low level indicating the absence of the A / V signal, the microcomputer 90 judges the signal detection data output from the data detection circuit 76, When the signal detection data is input from the high level, the power supply unit is controlled to turn on the power, switched to channel 3, and set to the channel.

After setting the channel 3 in this manner, the microcomputer 90 checks the output of the second signal detector 82. If the detection signal output from the second signal detector 82 is at the high level, the signal is terminated in the channel 3 state. If the detection signal is at the low level, the channel of the TV is set to 4.

The above-described process will be briefly described with reference to the flowchart of FIG. 3.

In step 41, it is determined whether the signal detected by the first signal detector 80 is high or low. If the detection signal is low, the flow advances to step 42 to determine whether the signal of the data detection unit 76 is high or low. In this case, too, if the data detection signal is low, it is considered that no video signal is generated from the VCR unit 50. However, if it is determined in step 41 that the detection signal is low, the power supply is immediately turned on (step 43), and the switch section 84 is switched to the line mode for transmitting the A / V line signal.

On the other hand, if it is determined in step 42 that the data detection signal is at the high level, after the power is turned on (step 45), the channel of the TV unit 100 is set to "3" (step 46). Thereafter, the process proceeds to step 47 in which the detection signal of the second signal detection unit 82 is determined. In this step 47, if it is determined that the detection signal is output as the high level, the power-on and channel 3 setting state is maintained as it is, and if it is determined that the detection signal is output as the low level, the tuner / IF module 78 Since the channel 3 is not tuned through the channel 3, the currently set channel 3 of the TV unit 100 is changed to channel 4.

Therefore, according to the present invention as described above, the convenience that can automatically control the mode of the TV according to the output of the VCR can be provided.

Claims (1)

According to the presence or absence of the A / V signal output from the VCR unit 50 including the video circuit 52 and the modulator 54, the A / V signal and the RF signal from the VCR unit 50 are selectively output. A mode switching device of a TV unit (50) having a switch (84), comprising: a video signal detection circuit (56) for detecting the presence or absence of a video signal from the video circuit (52); A first signal detector (80) for judging the presence or absence of an A / V signal from the video circuit (52) to switch the switch (84); A data generator (58) connected to the output of said signal detection circuit (56) for generating low frequency pulse data indicating the presence of a video signal; An adder (60) for adding the output from the modulator (54) and the output from the data generator (58); A low pass filter (72) for detecting the low frequency pulse data from the added signal output from the adder (60); A data detector (76) connected to the output of the low pass filter (72) to detect the presence of the low frequency data and to switch the TV unit (100) to a predetermined channel; A high pass filter (74) connected between the adder (60) and the tuner / IF module (78) to detect the RF signal from the added signal; A second signal detector (82) for determining the presence or absence of an RF signal from an output of the tuner / IF module (78) to switch the preset channel to another preset channel; The presence or absence of a line signal including a microcomputer 90 for controlling the TV unit 100 in response to signals detected from the data detector 76, the first signal detector 80, and the second signal detector 82, respectively. Television operating mode switching device.