JP3416324B2 - Recording and playback device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus,
In particular, it is interposed between a television receiver having a tuner capable of receiving a scrambled signal and a decoder for descrambling the scrambled signal, and outputs the descrambled signal input from the decoder to the television receiver via a buffer. And a recording / reproducing device. 2. Description of the Related Art Referring to FIG. 2, a conventional video tape recorder 1 includes connectors 1a and 1b. The video tape recorder 1 is connected to the television receiver 2 by the connector 1a and the connector 2a included in the television receiver 2, and is connected to the decoder 3 by the connector 1b and the connector 3a included in the decoder 3. The video tape recorder 1 also includes an antenna 1c, by which a high frequency signal received is provided to tuners 1e and 2b via a converter 1d. When the power switch (not shown) of the video tape recorder 1 is turned off, the tuner 1e does not operate and the switch S
W1 and SW4 are connected to terminals C1 and C6, as shown, by a control signal from the microcomputer 1h that operates even when the power switch is off. That is, the microcomputer 1h grasps the on / off state of the power switch, and connects the switches SW1 and SW4 to the terminals C1 and C6. Therefore, the video signal selected by the tuner 2b is supplied to the terminal C8 and the switch SW4
And to the decoder 3 via the buffer 1f. If the video signal is not a scramble signal by scramble broadcasting, the decoder 3 returns the video signal to the television receiver 2 via the switch SW1 and the buffer 1g without any processing. If so, the descrambling signal is returned to the television receiver 2 as described above, and the microcomputer 1h included in the video tape recorder 1 receives 1
A 2V determination signal is output. The microcomputer 1h receives this and turns on the switch SW2, thereby connecting the switch SW5 included in the television receiver 2 to the terminal C9. Therefore, if the video signal output from the tuner 2b is not a scrambled signal, the video signal supplied to the terminal C8 is output to the video amplifier circuit, but if the video signal output from the tuner 2b is a scrambled signal, Is descrambled by the decoder 3 and the terminal C9
Are output to the video amplifier circuit. The buffers 1g and 1f are connected to a switch SW
1 and SW4 have an ON resistance of at least several tens to several hundreds Ω, and are provided to compensate for the loss due to the ON resistance. Among them, the buffer 1g is configured as shown in FIG. . That is, the buffer 1g includes a transistor T1 whose collector is grounded, and the transistor T1 has an emitter connected to the transistor T1 via the emitter resistor R3.
Connected to 2V bias power supply. The base of the transistor T1 is grounded via a bias resistor R2, and is connected to a bias power supply via a bias resistor R1. This bias power is applied to the transistor T1 regardless of whether the power switch is on or off. The buffer 1g thus configured is connected to the switch SW1 via the coupling capacitor C1, and to the connector 1a via the coupling capacitor C2 and a resistor R4 for matching. More specifically, the base of the transistor T1 is connected to the coupling capacitor C1, and the collector of the transistor T1 is connected to the coupling capacitor C2.
Note that the buffer 1f is configured similarly to the buffer 1g. [0005] However, in such a conventional technique, the power switch of the video tape recorder 1 is turned off and the tuner 2 of the television receiver 2 is turned off.
Even when b is not receiving a scrambled broadcast, the bias power is applied to the buffers 1f and 1g, so that the respective biases 1g and 1f are always about 0.
The power of 3 W to 0.4 W was consumed. Of these buffers, the buffer 1f supplies the high-frequency signal output from the tuner 2b to the decoder 3, and makes the decoder 3 determine whether or not the high-frequency signal is a scramble signal, thereby controlling the switch SW5. However, the decoder 1e is completely meaningless,
It was wasting power. [0006] Therefore, a main object of the present invention is to provide a magnetic recording / reproducing apparatus capable of suppressing wasteful power consumption. SUMMARY OF THE INVENTION The present invention provides a television receiver having a tuner capable of receiving a scrambled broadcast in which a video signal has been scrambled, a descrambled scrambled broadcast, and a video signal output. The power switch of the recording / reproducing device is turned off in a recording / reproducing device which is interposed between the decoder and the decoder which outputs the discrimination signal at the time of descrambling and which outputs the video signal input from the decoder to the television receiver via the buffer. Detecting means for detecting the presence / absence of a discrimination signal when the power switch is turned off, and applying power to the buffer and detecting the absence of the discrimination signal when the detection means detects the presence of the discrimination signal when the power switch is off. Power switch means for shutting off power to the buffer when the , A recording / reproducing device. When the decoder descrambles the scramble signal given from the television receiver via the recording / reproducing device when the power switch of the recording / reproducing device is turned off, the decoder sends the signal to the recording / reproducing device. And outputs a descrambling signal and a discrimination signal. The recording / reproducing device detects this discrimination signal and supplies the discrimination signal to, for example, a switching circuit. As a result, the switching circuit is turned on, and power is applied to the buffer. Therefore, the descrambling signal is output to the television receiver via the buffer. According to the present invention, when the power switch is turned off, power is applied to the buffer only when the decoder descrambles the scramble signal, so that unnecessary power is consumed. Can be suppressed. The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings. Referring to FIG. 1, a recording / reproducing apparatus 10 of this embodiment is almost the same as the prior art shown in FIGS. 2 and 3, and the same points are denoted by the same reference numerals. A duplicate description will be omitted. The switching circuit 12 is interposed between the 12V bias power supply and the resistors R1 and R3. This switching circuit 12 includes a transistor T3, the emitter of which is connected to a bias power supply, the collector of which is connected to resistors R1 and R3, and the base of which is connected to the collector of transistor T4 via a resistor R6. A resistor R5 is inserted between the emitter and the base of the transistor T3. The emitter of the transistor T4 is grounded, the base is grounded via a resistor R8, and the diodes D1 and D1 are connected via a resistor R7.
2 output terminal. The input terminal of the diode D1 is
Turned on / off in response to power switch on / off 5
V, and an input terminal of the diode D2 is connected to the connector 1b and the microcomputer 1h. Therefore, the transistor T4 is turned on when the power switch is turned on or when a decision signal is given from the decoder 3, whereby the transistor T3 is turned on.
Becomes conductive. When the transistor T3 is turned on, a voltage of 12 V from the bias power supply is applied to the buffer 1g, and the buffer 1g is activated. As a result, the descramble signal given from the decoder 3 via the connector 1b is amplified by the buffer 1g, and the amplified descramble signal is output to the television receiver 2 via the connector 1a. According to this embodiment, the buffer 1g is activated only when the decoder 3 descrambles the scramble signal when the power switch is turned on or in the state where the power switch is turned off. Can be prevented. In this embodiment, the switching power supply of 5 V and the discrimination signal are applied to the base of the transistor T4 via the diodes D1 and D2.
May be controlled. That is, the microcomputer 1h
Knows the on / off state of the power switch and the presence / absence of a discrimination signal from the decoder 3, so that this control signal is supplied to the base of the transistor T4 when the power switch is turned on or when a discrimination signal is given. You may do so. Then, the diodes D1 and D2 become unnecessary, and the circuit configuration can be simplified.

[Brief description of the drawings] FIG. 1 is a circuit diagram showing one embodiment of the present invention. FIG. 2 is a block diagram showing a conventional technique. FIG. 3 is a circuit diagram showing a part of the related art. [Explanation of symbols] 10 Recording / reproducing device 12. Switching circuit 1g… buffer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 31/00 523 H04N 5/92 H04N 7/16

Claims (1)

(57) [Claim 1] A television receiver having a tuner capable of receiving a scrambled broadcast in which a video signal is scrambled, a descrambled scrambled broadcast to output a video signal, and A recording / reproducing apparatus interposed between a decoder that outputs a determination signal at the time of scrambling and outputting a video signal input from the decoder to the television receiver via a buffer, wherein a power switch of the recording / reproducing apparatus is Detecting means for detecting the presence or absence of the discrimination signal when it is turned off, and applying power to the buffer when the detection means detects that the discrimination signal is present when the power switch is off; and A power switch for shutting off the power to the buffer when detecting the absence of the discrimination signal; Characterized in that it comprises means, recording and reproducing apparatus.