JPS6029060Y2 - Unrecorded part detection device between songs - Google Patents

Description

[Detailed Description of the Invention] The present invention is directed to a musical tone recorded on a magnetic tape or a signal similar thereto (hereinafter simply referred to as a single musical tone signal).

) and a musical tone signal, that is, a device for detecting an unrecorded portion between songs.

Conventionally, when detecting a non-recorded portion between songs on a magnetic tape and switching from a fast-forward state to a constant-speed playback state or from a constant-speed playback state to a fast-forward state, the switching is usually performed using a tsuremade or the like.

Therefore, during the above switching, the power supply voltage may be disturbed by the operating current of the solenoid.

Also, change the tape speed to high speed during fast forwarding (20 to 3 @ constant speed).
), the brakes are applied to the tape take-up rail a moment earlier than the supply reel to prevent the tape from breaking. This causes sagging.

Therefore, not only does it take time for the tape to reach a constant speed, but also chattering of the tape relative to the magnetic head occurs.

Therefore, in combination with the above-mentioned disturbance in the power supply voltage, a pulse-like output is produced by the inter-track non-silver tone part detection device, and this pulse may cause a malfunction in which the tape returns to the fast-forward state.

In order to prevent such malfunctions in inter-track detection, the present invention is characterized by automatically prohibiting the operation of the inter-track unrelated note detection circuit for the time required for the tape to stabilize at a constant speed. shall be.

Hereinafter, the present invention will be specifically explained using the drawings.

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

In the figure, reference numeral 1 denotes an unrelated tone part detection circuit between songs, which includes a magnetic head 11, a musical tone signal amplifier 12, and a musical tone signal detector 1.
3. A musical tone signal integrator 14 and a waveform shaping Schmitt circuit 15 are included.

Reference numeral 2 denotes a solenoid device for switching from fast forward to constant speed, in which a transistor 21 and a solenoid 22 are included.

3 is a time delay circuit in which a diode 31, a capacitor 32 and a resistor 33 are included.

Reference numeral 4 indicates an electronic switch consisting of a transistor, 5 indicates an inter-musical detection output pulse, and 6 indicates a solenoid device drive pulse.

Now, when the unrecorded part between songs passes the magnetic head 11 in the tape fast forward state, the unrecorded part between songs detecting circuit 1 generates an inter-song detecting output pulse 5 at its output terminal.

This output pulse 5 is generated every time the inter-music unrecorded portion passes the magnetic head 11, and is sent to a counter (not shown) and counted.

When the counter counts the preset number of output pulses 5 required to locate the beginning of a desired song, it generates a solemade device drive pulse 6.

When the drive pulse 6 is applied to the base of the transistor 21 of the fast forward → constant speed switching solenoid device 2, the transistor 21 is turned on, the solenoid 22 is energized, and the tape fast forwarding state is switched from the tape fast forwarding state to the constant speed playback state by the drive system (not shown). The state is maintained.

The drive pulse 6 simultaneously quickly charges the capacitor 32 via the diode 31 of the delay circuit 3 and turns on the electronic switch 4 after a moment.

After the drive pulse 6 disappears, the electric charge charged in the capacitor 32 is blocked from flowing backward by the diode 31, and the electric charge charged in the capacitor 32 is blocked by the diode 31.
3 and through the pace emitter of the electronic switch (transistor) 4.

Thus, electronic switch 4 remains on for a time constant determined by capacitor 32 and resistor 33.

While the electronic switch 4 is on, the output pulse of the detection circuit 1 is not sent to the counter, and the operation of the detection circuit 1 is prohibited.

FIG. 2 is a waveform diagram for explaining the above-mentioned operation.

2A shows the driving pulse 6, FIG. 2B shows the on time T (time constant time) of the electronic switch 4, and FIG. 2C shows the output pulse 5' sent to the counter.

Therefore, in the circuit shown in Fig. 1, if the time constant of the time delay circuit 3 is set equal to the time required for the tape to stabilize at a constant speed, it will be possible to prevent the inter-track detection due to the above-mentioned false image pulses. Malfunctions can be prevented.

FIG. 3 shows another example of a malfunction prevention circuit that can be used in combination with the circuit of the present invention. In the figure, parts corresponding to those in FIG. do.

As mentioned at the beginning, the fast forward speed of current cassette tapes is 20 to 3 degrees at constant speed, so the reproduction frequency at that time is 20 to 3 degrees at constant speed.

Further, since the non-recording time between music tapes is 4 to 6 seconds, it is necessary to switch from fast forwarding to constant speed at 4 to 6/20 to 3@.

Therefore, if the time constant of the integrator (see 14 in Figure 1) is determined appropriately, when switching from constant speed to fast forward, malfunctions (detection output pulses) may occur at various times during musical tone playback in constant speed playback. The pianissimo section of the musical tone ends up moving to fast forward.

) occurs. In order to prevent this malfunction, the time constant of the musical tone signal integrator 14 should be set to about 20 to 3 o @ when fast forwarding at constant speed.
Just do it.

However, this needs to be done automatically.

In the circuit shown in Figure 3, the trigger signal is the drive pulse of the solenoid device used to change the tape speed.
The time constant of the integrator is changed.

Numeral 14' is an integrator which converts the musical tone signal into a DC signal like 14, but differs from 14 in that the resistance value of the resistor that determines the time constant can be changed.

Reference numeral 7 denotes a solenoid device for switching from constant speed to fast forwarding, in which transistors 71 and 73 and a solenoid 72 are included.

8 indicates a drive pulse for the solenoid device 7.

Reference numeral 9 denotes a holding circuit that holds the electronic switch 10 in the on state during tape fast forwarding.

When the drive pulse 8 is applied to the constant speed → fast forward switching solenoid device 7, the solenoid 72 is energized and the tape is switched to the fast forward state by a drive system (not shown), and the transistors 91 and 92 of the holding circuit 9 are turned on. , turn on the electronic switch 10.

The operation of this holding circuit 9 is maintained by a positive feedback holding current shown by arrow A.

When electronic switch 10 is turned on, resistor R' of integrator 14' is grounded, reducing the time constant of the integrator.

This state is maintained during tape fast forwarding.

Next, when the drive pulse 6 is applied to the fast forward constant speed switching solenoid device 2, the solenoid 22 is energized and at the same time the transistor 93 of the holding circuit 9 is turned on, and the positive feedback holding current of the transistors 91 and 92 is cut off. As a result, the holding circuit 9 is turned off, and therefore the electronic switch 10 is turned off, and the time constant of the integrator 14' is switched to a large value suitable for constant speed.

In this way, in the circuit shown in FIG. 3, malfunctions due to large changes in tape speed as described above are prevented, and the inter-track detection output pulse 5 can be obtained stably and reliably.

Figure 4 shows the situation. Therefore, if the circuit shown in FIG. 3 is used in combination with the present invention, it is possible to obtain an inter-music unrecorded portion detection device that completely prevents malfunctions.

In the explanation so far, the present invention has been described as relating to a device for detecting unrecorded sections between songs on a magnetic tape on which musical tone signals have been recorded. However, it can also be applied to cases where a signal similar to a musical tone signal is recorded, and the description of the unrecorded portion between songs in the name of the present invention and the scope of the claim for registration of a utility model is merely for convenience. I hope you understand that.

[Brief Description of the Drawings] Figure 1 is a circuit diagram showing an embodiment of the present invention, Figure 2 is a waveform diagram to explain its operation, and Figure 3 is a malfunction prevention that can be used in combination with the present invention. Circuit showing another example of the circuit, No. 4
The figure is an explanatory diagram of the operation. DESCRIPTION OF SYMBOLS 1... Circuit for detecting silver-free notes between songs, 2... Song fast forward constant speed switching solenoid device, 3... Time delay device, 4... Electronic switch, 5... . . . Song interval detection output pulse, 6 . . . Drive pulse for solenoid device 2.

Claims (1)

[Scope of utility model registration request] In a magnetic recording/playback device that detects a detection signal of a non-recording area between songs and switches the tape from a fast-forward state to a constant-speed playback state, the tape is played back for a certain period of time after detecting a detection signal of a non-recording area between songs in the fast-forward state. What is claimed is: 1. A sound part detecting device for detecting an unrecorded part between songs, characterized in that it is provided with means for inhibiting the operation of a detecting circuit for detecting an unrecorded part.