JPS6113284B2 - - Google Patents

Description

Detailed Description of the Invention The present invention records different detection signals on a magnetic tape depending on whether or not a noise reduction circuit is used, and detects the detection signals to determine whether or not a noise reduction circuit is used. - A tape recorder capable of detecting nothing will be described in detail below with reference to the drawings.

FIG. 1 is an embodiment of the present invention, FIG. 2 is an output waveform diagram, and FIG. 3 is an explanatory diagram of a magnetic tape. 1 and 2 are input terminals for left and right channels, 3 and 4 respectively.
1 is a preamplifier circuit, 5 and 6 are noise reduction circuits, 7 and 8 are recording amplifier circuits, 9 and 10 are recording magnetic heads, 11 and 12 are monitor amplifier circuits, 1
3 and 14 are output terminals connected to input terminals of an amplifier having a large output. Reference numerals 15 and 16 designate first and second one-shot multivibrators, which operate in reverse when a non-lock operation switch 17 connected between the input terminals of the multivibrators 15 and 16 and the ground is closed, and operate for a predetermined time L. Outputs a (low) level signal. Reference numeral 18 denotes a third one-shot multivibrator which operates inverted when the first one-shot multivibrator 15 returns to a steady state after performing an inverted operation for a predetermined time and outputs an L level signal for a predetermined time; A capacitor 19 and a resistor 2 are connected between the input terminal of the multivibrator 18 and the output terminal of the first one-shot multivibrator 15.
A differential circuit consisting of 0 and an inverter 21 are connected. 22 inputs the output signals of the first one-shot multivibrator 15 and the third one-shot multivibrator 18.
The NAND circuit 23 is a driving transistor that drives a relay 26 that switches switches 24 and 25 connected between the noise reduction circuits 5 and 6 and the recording amplifier circuits 7 and 8, and its base is the
It is connected to the NAND circuit 22. 27 and 28
are transistors that control signals output to the output terminals 13 and 14, and each base is connected to the NAND circuit 22. 29 is the first
The output terminal A is connected to a first detection signal supply path 32 via resistors 30 and 31, and to a second detection signal supply path 35 via resistors 33 and 34. It is connected. 36 is a second oscillation circuit that generates a second detection signal with a frequency different from the frequency of the first detection signal, and its output terminal B is connected to the first detection signal supply circuit 32 via resistors 37 and 38; It is also connected to the second detection signal supply path 35 via resistors 39 and 40. The first detection signal supply path 32 is connected to the contact 24 of the switch 24 which is switched by driving the relay 26.
a, and the second detection signal supply path 35 is connected to the contact 25b of the other switch 25. 4
1 is the second one-shot multivibrator 16
and third one-shot multivibrator 18
This is a NAND circuit that receives the output signal of 42
and 43 are the first detection signal supply path 32 and the second detection signal supply path 32;
This is a muting transistor whose collector and emitter paths are connected between the detection signal supply path 35 and the ground, respectively, and its base is connected to the NAND circuit 41. 44 is a noise reduction circuit 5,
6 (not shown)
One terminal 44a is grounded, and the other terminal 44b is connected to a power source via a resistor 45. 46 is a selection switch that is switched in conjunction with a switch (not shown) that switches an equalizer or the like according to the characteristics of the magnetic tape; one terminal 46a is grounded, and the other terminal 46b is connected to the power supply via a resistor 47; It is connected. 48 is a first control transistor whose collector-emitter path is connected between the connection point C of the resistors 30 and 31 and ground in order to control the output signal from the first oscillation circuit 29 to the first detection signal supply path 32; and its base is connected to the terminal 44b of the switch 44. 49 is a second detection signal supply path 3 from the first oscillation circuit 29
Resistors 33 and 34 to control the output signal to 5.
A second control transistor is connected between the ground point D and the ground collector-emitter path, and its base is connected to the terminal 46b of the selection switch 46. 50 is a third control transistor whose collector-emitter path is connected between the connection point E of the resistors 37 and 38 and ground in order to control the output signal from the second oscillation circuit 36 to the first detection signal supply path 32; The base thereof is connected to the terminal 44b of the switch 44 via the inverter 51. 52 is a fourth control transistor whose collector-emitter path is connected between the connection point F of the resistors 39 and 40 and ground in order to control the output signal from the second oscillation circuit 36 to the second detection signal supply path 35; and its base is the inverter 53
The terminal 46b of the selection switch 46 is connected to the terminal 46b of the selection switch 46 via the terminal 46b. In this circuit configuration, the inversion operation time of the first one-shot multivibrator 15 is set to be longer than the inversion operation time of the second one-shot multivibrator 16. Further, a capacitor 54 connected in parallel to the operation switch 17 is for preventing malfunction.

The present invention is constructed as described above, and its operation will be explained next. First, to explain the normal recording operation, the recording signals input to the input terminals 1 and 2 of the left and right channels are sent to the preamplifier circuits 3 and 4, respectively.
The signal is applied to recording magnetic heads 9, 10 through noise reduction circuits 5, 6, switches 24, 25, and recording amplifier circuits 7, 8, and is recorded on a magnetic tape. In addition, the recording signal is amplified by monitor amplifier circuits 11 and 12, and then output as a monitor signal to the output terminal 1.
3 and 14.

Although the normal recording operation is performed in this way, the detection signal recording operation, which is the gist of the present invention, will be explained next. In the illustrated state, the first one-shot multivibrator 15, the second one-shot multivibrator 16, and the third one-shot multivibrator 18 are in a steady state, and an H (high) level signal is output to their output terminals. . Therefore, the output of the NAND circuit 22 which receives the output signals of the first one-shot multivibrator 15 and the third one-shot multivibrator 18 becomes L level. Therefore, the NAND circuit 2
The driving transistor 23 and the transistors 27 and 28, to which the output signal No. 2 is applied to the base, are in a non-conducting state. Similarly, the output signals of the second one-shot multivibrator 16 and the third one-shot multivibrator 18 are input.
The output of the NAND circuit 41 is at L level, and the muting transistors 42 and 43 to which this signal is applied to their bases are both non-conductive. In such a state, when the operation switch 17 is closed, the first one-shot multivibrator 15, the second one-shot multivibrator 16, and the third one-shot multivibrator 18 operate in reverse. It will look like Figure 2. Figure 2 a, b, and c are the first and second
and third one-shot multivibrator 1
5, 16, and 18 output waveforms,
T ₀ is the point at which the operating switch 17 is closed. T ₀
At this point, the first and second one-shot multivibrators 15 and 16 operate inverted, and their outputs are inverted from H level to L level. Then, after ₁ hour, the second one-shot multivibrator 1
6 is inverted to a steady state, and its output becomes H level rather than L level. Also, after T ₂ hours, the first
The one-shot multivibrator 15 is reversed to a steady state, and its output changes from the L level to the H level, and in conjunction with this, the third one-shot multivibrator 18 is reversed and its output remains at the L level until _T3 . When the operation switch 17 is closed, the first one-shot multivibrator 15 operates in reverse, and its output becomes L level, so the NAND
The output of the circuit 22 becomes H level, and the first level is reached at the _T2 point.
The one-shot multivibrator 15 reverses and returns to the steady state, and its output becomes H level. However, when the first one-shot multivibrator 15 returns to inversion, the third one-shot multivibrator 18 is inverted and its output goes to L level, so the output of NAND circuit 22 goes to H level. Therefore, the output of the NAND circuit 22 is at the _T0 point when the operation switch 17 is closed, and the third one-shot multivibrator 18 is inverted to a steady state.
It will be at H level until T ₃ points. Therefore, between the drive transistor 23 and the transistor 2
7 and 28 become conductive, switching the switches 24 and 25 to the opposite side from the illustrated state and bypassing the signals output to the output terminals 13 and 14.
In addition, the second one-shot multivibrator 16
and third one-shot multivibrator 18
When the output signal of is input, the output of the NAND circuit 41 is
From T ₀ to T ₁ and from T ₂ to T ₃ , the level is H.
The level is L from T ₁ to T ₂ . Therefore from T ₀
Between T ₁ and T ₂ to T ₃ , the muting transistors 42 and 43 are conductive to bypass the signal flowing through the first detection signal supply path 32 and the second detection signal supply path 35, so that the recording amplifier circuit The input signals 7 and 8 disappear, and no-signal areas P and Q are formed on the magnetic tape T during that time. Moreover, since the muting transistors 42 and 43 are in a non-conductive state between T ₁ and T ₂ , the first detection signal supply path 32
The signal flowing through the second detection signal supply path 35 is applied to the recording amplifier circuits 7 and 8 without being bypassed, and is recorded on the magnetic tape. Next, the signals flowing through the first detection signal supply path 32 and the second detection signal supply path 35 will be explained. In the illustrated state, both the switch 44 and the selection switch 46 are open, so the first control transistor 48 and the second control transistor 49 are in a conductive state, and the third control transistor 50 and the fourth control transistor 52 are in a non-conductive state. It is in. Therefore, in this state, the signal flowing through the first detection signal supply path 32 and the second detection signal supply path 35 is the second signal from the second oscillation circuit 36.
This second detection signal is recorded on a magnetic tape by recording magnetic heads 9 and 10. Furthermore, when the switch for controlling the operation and deactivation of the noise reduction circuits 5 and 6 is changed over, the switch 44 is closed and the first
The control transistor 48 becomes non-conductive, and the third control transistor 50 becomes conductive. Therefore, in this case, the first detection signal from the first oscillation circuit 29 flows through the first detection signal supply path 32, and the second detection signal flows through the first detection signal supply path 32.
A second detection signal from a second oscillation circuit 36 is supplied to the detection signal supply path 35 and is recorded on a magnetic tape by recording magnetic heads 9 and 10. Furthermore, select switch 4
6 is closed, the second control transistor 49 becomes non-conductive, and the fourth control transistor 52
becomes conductive, so the first detection signal from the first oscillation circuit 29 flows through the second detection signal supply path 35 and is recorded on the magnetic tape by the recording magnetic head 10. FIG. 3 shows the state of the magnetic tape recorded by the above-mentioned operation. When the operation switch 17 is closed and the tape recorder is put into the detection signal recording operation state, there is a no-signal section from T ₀ to T ₁ . P is formed, then the first detection signal or the second detection signal is recorded from T ₁ to T ₂ , and then from T ₂ to T ₃
A no-signal part Q is formed up to

As explained above, in the present invention, one of two detection signals of different frequencies is recorded on a magnetic tape depending on whether or not a noise reduction circuit is used. Since the detection signal is detected, the detection operation can be performed reliably without causing the problem of detecting the presence/absence of a single detection signal, which is the problem of detecting non-signal parts in music etc. It has the advantage that it can be done. Furthermore, the present invention is characterized in that not only the detection signal is simply recorded on the magnetic tape, but also a no-signal area is formed before and after the recording position of the detection signal. This has the advantage that the detection signal can be easily distinguished from the music signal without recording the detection signal on a special track, and the detection operation of the detection signal can be performed more reliably. have.

[Brief explanation of the drawing]

FIG. 1 is an embodiment of the present invention, FIG. 2 is an output waveform diagram, and FIG. 3 is an explanatory diagram of a magnetic tape. Explanation of main drawing numbers 3, 4...Preamplifier circuit, 5,
6... Noise reduction circuit, 7, 8... Recording amplifier circuit,
9, 10...Magnetic head for recording, 15...First one-shot multivibrator, 16...Second one-shot multivibrator, 17...Operation switch, 18...Third one-shot multivibrator, 23...Drive transistor, 29...No. 1 oscillation circuit, 32...first detection signal supply path, 35...second
Detection signal supply path, 36...Second oscillation circuit, 42, 4
3... Muting transistor, 48... First control transistor, 49... Second control transistor, 50... Third control transistor, 52...
Fourth control transistor.

Claims (1)

[Claims] 1. First and second oscillation circuits that generate first and second detection signals of different frequencies, respectively, an operation switch that is switched during the detection signal recording operation, and when the operation switch is switched, it becomes operational and remains in operation for a predetermined period of time. A control circuit that puts the tape recorder in a detection signal recording operation state, and a detection signal control that changes the state by switching the operation of a noise reduction circuit or the like and controls the output operation of the detection signal from the first and second oscillation circuits. When the detection signal is recorded by switching the operation switch, the control circuit and the detection signal control circuit control the first control circuit.
A tape recorder characterized in that either one of the detection signal or the second detection signal is selected and recorded on a magnetic tape, and a no-signal portion is formed before and after the recording position of the detection signal.