KR910003392Y1 - Broadingcast signal/playback selection switching circuit of video cassette recorder - Google Patents

Abstract

No content.

Description

Broadcasting signal / playback signal selection switching circuit of video cassette recorder

1 is a block diagram showing a video cassette recorder configured with a selective switching circuit of the present invention.

FIG. 2 is a detailed circuit diagram showing the switching part of FIG.

* Explanation of symbols for main parts of the drawings

10: VCR 11: Tuner part

12: playback unit 13: high frequency signal conversion unit

14: selection switching circuit 20: TV

141: first switching unit 142 second switching unit

SW1: Broadcast signal / playback signal selector switch SW2: VCR / TV mode selector switch

TR1-TR5: Transistor R1-R12: Resistor

V / : VCR / TV mode selection signal input terminal PHL: Playback control signal input terminal

D: Diode

The present invention is a video cassette recorder (hereinafter abbreviated as VCR) in which a television receiver (hereinafter abbreviated as TV) by selectively switching a television broadcast signal tuned by a tuner unit with a built-in VCR and a signal reproduced from a video tape. The present invention relates to a broadcasting signal / playback signal selection switching circuit of a video cassette recorder which is outputted to a video cassette recorder.

In general, when a TV is connected to a VCR to selectively watch a television broadcast signal or a playback signal of a video tape, the VCR is used in a region that adopts the National Television System Committee (NTSC) method such as Korea, Japan, and the United States. / TV mode is configured.

The VCR / TV mode refers to a VCR mode that converts a television broadcast signal or a video tape tuned by a tuner unit with a built-in VCR into a high frequency signal of channel 3 or channel 4 and outputs it to a TV for viewing. The tuner unit built in the TV mode selects a TV mode for viewing and tuning.

In the VCR having the VCR / TV mode configured as described above, in the state where conventionally a video tape is played on a VCR to be viewed on a TV, the VCR / TV mode switch of the VCR is in the VCR mode, and the tuner section of the TV is set to channel 3 or Since it is set to channel 4, the user operates the VCR / TV mode key to watch a television broadcast signal. At this time, the user operates the VCR / TV mode key to watch a television broadcast signal. After the mode selection switch is set to the TV mode, the tuner portion of the TV receiver has to be set to the channel of the television broadcast signal that the user wants to watch.

In addition, when the VCR / TV mode selection switch is set to the VCR mode and the VCR is in the stop mode, the tuner unit built in the VCR may be set to watch a desired television broadcast signal, but this is necessary when the VCR is in the stop mode. Not only does it take a lot of time, but also when watching a playback signal of a videotape while watching a television broadcast signal, there is a drawback that it takes a lot of time without a need for a playback signal to be output to the TV.

Accordingly, an object of the present invention is to provide a selective switching circuit for selectively watching a television broadcast signal or a playback signal of a video tape tuned by a tuner unit having a built-in VCR in response to pressing a VCR / TV mode key so that it can be viewed on a TV. There is.

In order to achieve the above object, the selective switching circuit of the present invention uses the VCR / TV mode selection switch when the VCR / TV mode selection switch selects the VCR mode when the playback mode is selected and the VCR / TV mode key is pressed when the playback mode is not the playback mode. A first switching unit for selecting a mode and a broadcast signal / playback signal when the broadcast signal / playback signal switch selects the broadcast signal when the play mode is not in the play mode, and presses the VCR / TV mode key in the play mode. And a second switching section for selective switching.

According to the present invention having such a configuration, when the play key of the VCR is pressed to the play mode, the VCR / TV mode selector switch selects the VCR mode regardless of whether the VCR / TV mode key is pressed under the control of the first switching unit. 2 The switching unit selects and controls the broadcast signal or playback signal by switching the broadcast signal / playback signal selection switch to the VCR / TV mode selection signal inputted by pressing the VCR / TV mode key. Therefore, the VCR presses the VCR / TV mode key. In accordance with the present invention, a tuned television broadcast signal or a playback signal of a video tape is selectively output to a TV through a broadcast signal / playback signal selection switch and a VCR / TV mode selection switch.

In the non-playback mode, the second switching unit controls the broadcast signal / playback signal selection switch to select a broadcast signal regardless of whether the VCR / TV mode key is pressed, and the first switching unit presses the VCR / TV mode key. By switching the VCR / TV mode selection switch to control the VCR mode or TV mode, the TV broadcast signal tuned by the VCR built-in tuner unit can be controlled through the broadcast signal / playback signal selection switch and the VCR / TV mode selection switch. The TV broadcast signal may be tuned by a tuner unit with a built-in TV or a built-in TV.

Hereinafter, the selective switching circuit of the present invention having the above object and configuration will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, a broadcast signal / playback signal selector switch SW1 selects a playback signal of a television broadcast signal tuned by the tuner section 11 or a video tape played back by the playback section 12, and converts a high frequency signal. In the VCR 10, which is inputted to the unit 13 and the output signal of the high frequency signal conversion unit 13 or the television broadcast signal is output to the TV 20 through the VCR / TV mode selection switch SW2, the VCR VCR / TV mode selection signal input terminal (VCR / In response to the VCR / TV mode selection signal inputted to the VCR / TV mode selection signal and the playback mode signal inputted to the reproduction mode signal input terminal PBH, the selection switching circuit 14 performs the broadcast signal / playback signal selection switch SW1 and VCR / TV mode. The selection switch SW2 is controlled.

FIG. 2 is a detailed circuit diagram of the selection switching circuit 14. As shown therein, the VCR / TV mode selection input terminal V / ) Is connected to the emitter of the transistor TR1 and the VCR / TV mode selection signal input terminal (V / ) And the regeneration signal input terminal PBH are commonly connected to the base of the transistor TR1 through the resistors R1 and R2, respectively, and the regeneration control signal input terminal PBH is through the diode D and then the transistor TR1. Is connected to the base of the resistor R4 and the transistor TR2 through the resistor R3 together with the collector of < RTI ID = 0.0 > (R) < / RTI > The collector of the transistor TR3 is connected to the control terminal of the VCR / TV mode selector switch SW2 to form the first switching unit 141 and the input terminal V /. ) Is connected to the base of the resistor R7 and the transistor TR4 to connect the collector of the transistor TR4 to the resistor R8 and to the base of the resistor R10 and the transistor TR5 through the resistor R9. The collector of the transistor TR5 was connected to the control terminal of the broadcast signal / playback signal selection switch SW1 together with the input terminal through the resistor R11 to form the second switching unit 142.

In the above, the VCR / TV mode selection signal input terminal (V / The high potential is input in the VCR mode, the low potential is input in the TV mode, and the high potential is input in the playback control signal input terminal PBH in the playback mode. Code Vcc is a power supply terminal.

In the selective switching circuit of the present invention configured as described above, when the user presses the play key to put the VCR into the play mode while the power supply terminal (Vcc) is applied, the high potential is input to the play control signal input terminal (PBH). Transistor TR1 is turned off because it is applied to the base of transistor TR1 through R2, and the high potential of the regeneration control signal input terminal PBH is applied to the transistor TR2 through the diode D and the resistor R3. Is applied to the base of the transistor, and the power supply of the power supply terminal Vcc flows through the transistors TR2 through the resistors R6 and R5, thereby applying a low potential to the base of the transistor TR2, thereby turning on the transistor TR3. The power supply of the power supply terminal Vcc is applied to the control terminal of the VCR / TV mode selection switch SW2 through the transistor TR3 so that the selection switch SW2 is shorted to one fixed terminal a2, that is, the selection switch is VCR / TV mode selection signal input terminal (V / Irrespective of the potential input to), it is short-circuited in the playback mode to select the VCR mode.

In this state, when the user presses the VCR / TV mode key, the VCR / TV mode selection signal input terminal (V / When the high potential is input to the high potential, the input high potential is applied to the base of the transistor TR4 so that it is turned on, and the transistor TR5 is open so that the high potential input to the input terminal PBH is transmitted through the resistor R11. The play signal of the video tape which is applied to the control terminal of the broadcast signal / playback signal selector switch SW1 and is short-circuited to the fixed terminal a1 of the movable terminal of the selector switch SW1, and thus reproduced by the playback unit 12. Is converted into a high frequency signal by the high frequency signal converter 13 through the selection switch SW1 and then output to the TV 20 through the selection switch SW2.

Then press the VCR / TV mode key again to enter the input terminal (V / In contrast, the transistor TR4 is turned off and the transistor TR5 is turned on, so that a low potential is applied to the control terminal of the selector switch S1 so that the movable terminal is fixed to the other side. The TV broadcast signal tuned by the tuner unit 11 is converted into a high frequency signal by the high frequency signal converting unit 13 by the selection switch SW1 and then output to the TV 20 through the switch SW2.

That is, when the VCR is in the playback mode, when the VCR / TV mode key is pressed, the playback signal of the video tape reproduced by the playback unit 12 or the television broadcast signal tuned by the tuner unit 11 is output to the TV 20. Therefore, if the user sets the channel of the tuner unit 11 to tune the desired television broadcast signal, the user can selectively watch the desired television broadcast signal or the playback signal of the video tape by pressing the VCR / TV mode key. .

On the other hand, in the non-playback mode, since the low potential is input to the input terminal PBH, the input terminal V / The low potential is applied to the control terminal of the selector switch SW1 regardless of the potential of the switch), the movable terminal is short-circuited to the other fixed terminal b1, and the television broadcast signal tuned by the tuner section 11 is selected by the selector switch SW1. Through the high frequency signal converter 13 is converted into a high frequency signal and output.

In this state, press the VCR / TV mode key to enter the input terminal (V / When the high potential is input to the input terminal, the input high potential flows through the resistors R1 and R2 to the input terminal PBH while applying a low potential to the base of the transistor TR1 so that it is turned on. ) Is applied to the base of the transistor TR2 through the transistor TR1 and the resistor R3 to turn on the transistor TR2. Accordingly, the transistor TR3 is turned on to control the terminal of the selection switch SW2. Since the high potential is applied to the movable terminal of the selector switch SW2, the output signal of the tuner unit 11, which is short-circuited to one fixed terminal a2 and converted into a high frequency signal by the high frequency signal conversion unit 13, is Inputted to 20 through selection switch SW2.

Then, press the VCR / TV mode key on the input terminal (V / In contrast, the transistor TR1 is turned off, the low potential is applied to the base of the transistor TR2, and the transistor TR3 is turned off, and the transistor TR3 is turned off. The low potential is applied to the control terminal, and the movable terminal is short-circuited to the other fixed terminal b2.

Therefore, the output signal of the high frequency signal converter 13 is not input to the TV 20, the TV broadcast signal is input to the TV 20 through the switch SW2, and the TV 20 is a tuner part built therein. The television broadcast signal is tuned.

That is, when the VCR 10 is not a playback board, the tuner unit 11 watches the tuned television broadcast signal tuned to the TV 20 by pressing the VCR / TV mode key or the tuner unit in which the TV 20 is built. The tuned television broadcast signal is viewed.

As described in detail above, the present invention enables the user to use the VCR more conveniently by allowing the user to watch the playback signal of the videotape or the desired television broadcast signal by pressing the VCR / TV mode key while the videotape is playing. It is effective.

Claims (2)

The broadcast signal / playback signal selection switch SW1 selects the tuner 11 tuned television broadcast signal or the video tape played back by the playback section 12, and inputs it to the high frequency signal conversion section 13, In a video cassette recorder in which the output signal of the high frequency signal conversion section 13 is output to the TV 20 through the VCR / TV mode selection switch SW2, the VCR mode when the selection switch SW2 is in the playback mode. Is selected and the playback mode is not in the playback mode, the first switching unit 141 for switching to the VCR mode or the TV mode by pressing the VCR / TV mode key, and the selection switch SW1 is the VCR / TV in the ashing mode. Selecting a broadcast signal / playback signal of a video cassette recorder, characterized in that the second switch unit 142 selects a broadcast signal or a play signal according to pressing a mode key, and selects a broadcast signal when the play mode is not in the play mode. Switching times in. The VCR / TV mode selection signal input terminal (V / ) And the reproduction signal input terminal PBH are connected to the emitter and the base side of the transistor TR1, the input terminal PBH is connected to the collector side of the transistor TR1, and the transistor TR2 is connected. ) Is connected to the base side of transistor TR3, and the collector of transistor TR3 is connected to the control terminal of selection switch SW2 to form the first switching unit 141, and the input terminal V / ) Is connected to the base of the transistor TR4 and its collector is connected to the transistor TR5 to the base, and the collector of the transistor TR5 is connected to the control terminal of the selection switch SW1 together with the input terminal PBH side. And a second switching unit (142). A broadcasting signal / playback signal selection switching circuit of a video cassette recorder.