KR900008436Y1 - Audio sound correction circuit in double deck cassette - Google Patents

Abstract

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Description

Double deck sound quality correction circuit

Circuit diagram of the present invention.

* Explanation of symbols for main parts of the drawings

5: Dolby Circuit 6: Double Voltage Rectifier

10: motor drive unit 15: dubbing detection unit

20: automatic level control circuit SW ₁ : function switching switch

SW _3-1 , SW _3-2 : Recording Playback Switch SW ₄ : Dolby Selection Switch

LS ₁ , LS ₂ : Life switch AM, BM: Motor

Q ₁ , Q ₂ , Q ₃ : Transistor

The present invention, in the double deck with a built-in Dolby circuit and automatic level control circuit, stops the operation of the Dolby circuit and the automatic level control circuit during dubbing, so that accurate dubbing operation can be performed without changing the sound quality. A double deck sound quality correction circuit that can be performed.

The double deck has a merit that it can perform a dubbing function in which the main deck capable of recording and playback and the auxiliary deck capable of playing only can be copied to the main deck as they are.

However, if the double deck is equipped with a Dolby circuit and an automatic level adjustment circuit, the sound quality can be expected to be improved by removing the noise of the beep during playback and limiting the over-input to lower the normal beep. The original sound was not dubbed, and the altered sound was recorded through the Dolby circuit and the automatic level adjustment circuit, so that the original sound could not be dubbed.

That is, at the time of dubbing, the signal sound higher than the level set by the automatic level adjustment circuit is applied to the signal sound of the set level by limiting this, so that the original signal sound higher than the set level cannot be faithfully dubbed.

In view of this, the present invention allows sound quality to be corrected by driving the Dolby circuit and the automatic level adjustment circuit, which are sound quality correction circuits, during normal playback (including continuous playback) and during recording other than dubbing, and when performing the dubbing function. It is intended to provide a double deck that can dub the original sound as it is blocked by the sound quality correction circuit as described in detail by the accompanying drawings as follows.

The input signal is configured to be output as a recording and reproducing signal through an automatic level adjusting circuit 20 for limiting over-input and a Dolby circuit 5 for removing noise. 20. In a double deck having a double voltage rectifying unit 6 configured to control the driving of the 20 and a general motor driver 10, a dubbing detector 15 for detecting a dubbing voltage during a dubbing operation, and a dubbing detector 15 The transistor Q _{4 which} is driven when the dubbing voltage is detected by the 15 and stops the driving of the automatic level adjustment circuit 20 and the driving is stopped when the dubbing voltage is detected by the dubbing detector 15 to drive the Dolby circuit 5. It consists of a transistor (Q ₈ ) for stopping the.

In other words the diode in the present design is the input signal with automatic level control for limiting the input circuit 20 and the Dolby circuit 5, recording, and voltage doubler rectifying section (6) the output signal according As the output to the reproduced signal through the (D ₃ -D ₆ ) is configured to control the driving of the transistor Q ₅ by controlling the driving of the transistor Q ₅ to control the driving of the over-input limiting transistor Q ₆ (Q ₇ ) of the automatic level adjustment circuit 20 and supply the power B ^In the double deck in which the motor driver 10 is configured such that +) is applied to the motor AM (BM) to which the simultaneous operation preventing transistor Q ₁ is connected through the leaf switch LS ₁ (LS ₂ ). , is the drive of the transistor (Q ₂₎ (Q ₃₎ of the dubbing detector 15 is controlled in accordance with the switching state of the function change-over switch (SW ₁₎ and a playback switch (SW _3-1) detects a voltage at the time of dubbing, the dubbing The dubbing voltage of the dubbing detector 15 blocks the driving of the automatic level adjustment circuit 20. And and at the same time controlling the drive of the transistor (Q ₄₎ adapted to control the drive of the transistor (Q ₈₎ to block the operation of the Dolby circuit 5.

SW ₁ is switched to the tape position as a function change switch, SW _3-1 and SW _3-2 are switched to the play position as the interlocked recording and playback switch, and SW ₄ is switched to the “off” position with the Dolby selection switch. have.

The input terminal P ₁ of the Dolby circuit 5 is a power supply terminal and the input terminal P ₂ drives the Dolby circuit 5 when the power supply B "is applied in the reproducing state or the power supply B" is applied in the recording state. Let's go.

In the present invention configured as described above, a general recording operation other than the dubbing operation will be described.

At this time, only the main deck which performs recording and reproduction is driven. When the life switch LS ₁ interlocked by the recording button is turned "on", the power source B is connected to the motor BM through the life switch LS ₁ . The main deck motor (BM) is in a recording state, so that the recording / playback switch (SW _3-1 ) (SW _3-2 ) is switched to the recording position opposite to the drawing. do.

And Leif switch (LS ₁₎ is "on" when the transistor is applied to the high level to the base of (Q ₁₎ transistor (Q ₁₎ is "off" causes and also does not drive the read only type auxiliary dekkeo Leif switch Since the LS ₂ is turned off, the motor AM is not driven and at the same time, the power supply B ⁺ is not applied to the dubbing detector 15, so that the transistor Q ₂ Q ₃ is turned off. It becomes a state.

Transistor (Q ₂₎ is "off" when the transistor (Q ₄₎ is "off" as soon at the same time the transistor (Q ₈₎ is self-leveling as "turn-on", "off" of to be on and the transistor (Q ₄₎ circuit ( 20 is driven by the output of the double-voltage rectifier 6, the power (B) is applied to the Dolby selection switch (SW ₄ ) by the "turn on" of the transistor (Q ₈ ), so that the Dolby switch (SW ₄₎ ), Driving of the Dolby circuit 5 is selected.

That is, when the Dolby switch SW ₄ is "on", the power supply B ⁺ is applied to the input terminal P ₂ to drive the Dolby circuit 5, and when the Dolby switch SW ₄ is "off", the Dolby circuit ( 5) is not driven.

The transistor (Q ₄₎ in the "off" when the level above the input signal is set to be driven by the output of the automatic level control circuit 20 is voltage doubler rectifying section (6) is applied to the transistors in the voltage doubler rectifying section (6) in (Q ₅₎ a "turn-on" and set below the level is a transistor (Q ₅₎ thereby "turned off".

Therefore, when the over-input signal is applied, the transistor Q ₅ is "turned on", thereby lowering the over-input signal input by "turning on" the transistors Q ₆ (Q ₇ ), so that only the normal input signal is applied.

Therefore, in the normal recording operation, the Dolby circuit 5 and the automatic level adjustment circuit 20 are normally driven.

Next, the states of the dubbing operation different from the above will be described.

When the dubbing operation is performed, the reproduction signal of the auxiliary deck is copied to the main deck so that the life switch LS ₁ and LS ₂ are both kept "ON" by the recording and playback buttons. _3-1 ) (SW _3-2 ) are all connected to the recording terminal (R) and the function switching switch (SW ₁ ) is switched to the tape position.

Therefore, the power B " applied through the life switch LS ₁ operates the motor BM to perform recording in the main deck, and the power B " applied through the life switch LS ₂ Regardless of " turning off " of the transistor Q ₁ , the auxiliary deck is applied to the motor AM through the recording / playback switch SW _3-1 to perform the playback operation.

At this time, the power source B ⁺ applied to the auxiliary deck motor AM is applied to the dubbing detector 15, and a high level is applied to the base of the transistor Q ₃ through the function switch SW ₁ . When Q ₃ ) is "turned on" and transistor Q ₃ is "turned on", a low level is applied to the base of transistor Q ₂ , causing transistor Q ₃ to be "turned on".

That is, only during the dubbing operation, the transistor Q ₂ of the dubbing detector 15 is “turned on” to detect the dubbing voltage.

And a transistor (Q ₂₎ that the diode (D ₁₎ (D ₂₎ of Sikkim a transistor (Q ₄₎ "turn-on" at the same time the transistor (Q ₈ via the collector-side high-level output when the "turn on" the transistor (Q ₂₎ ) Is "turned off".

When transistor Q ₄ is " turned on " transistor Q ₅ of automatic level adjustment circuit 20 is " turned off " regardless of the output of double voltage rectifier 6, so transistor Q ₆ (Q ₇ ). Is maintained in the " turn off " state so that the driving of the automatic level adjustment circuit 20 is interrupted.

And a transistor (Q ₈₎ is "off" so when Dolby selection switch (SW ₄₎ to the power supply (B ⁺⁾ is not applied even when "on", the Dolby selection switch (SW ₄₎ Dolby circuit 5 is not driven Will not.

Therefore, the beep sound reproduced in the auxiliary deck can be dubbed as the original sound without altering the beep sound in the automatic level adjustment circuit 20 and the Dolby circuit 5.

As described above, the present invention corrects the sound quality of the input signal by driving the Dolby circuit 5 and the automatic level adjustment circuit 20 when recording other than normal playback and dubbing, and enjoys a good sound quality and performs a dubbing function. At the time, the driving of the Dolby circuit 5 and the automatic level adjustment circuit 20 is cut off so that the original sound of the auxiliary deck is copied to the main deck as it is, so that sound quality deformation can be prevented. There is an advantage that can be widely applied to the double deck of intermediate or higher.

Claims (1)

The recording and reproducing signal is applied through the automatic level adjusting circuit 20 and the Dolby circuit 5 for limiting over-input, and the voltage is rectified by the double voltage rectifying unit 6 to drive the automatic level adjusting circuit 20. In the double deck which is controlled and includes a conventional motor driver 10, the transistor Q ₂ and Q ₃ are switched according to the driving state of the motor driver 10 and the switching state of the function switching switch SW ₁ . A dubbing detector 15 for detecting a dubbing voltage by driving, a transistor Q ₄ driven by an output of the dubbing detector 15 to control driving of the automatic level adjustment circuit 20, and the dubbing detector 15 A double deck sound quality correction circuit comprising a transistor (Q ₈ ) driven by the output of the control circuit to control the driving of the Dolby circuit (5).