JPS59218649A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the continuous reproduction with no interruption by having such a circuit constitution where a tape is put automatically rapid traverse mode up to its termination and then reversed automatically and at the same time a recording/reproducing device is put into a reproduction mode in case the reproduction is through with the sound information before the tape reaches its termination. CONSTITUTION:The reproduction is started, and a transistor TR25 is turned on via an amplifier 18 and a rectifying circuit 19 if a signal exists on a tepe. Thus a capacitor 29 is not charged. However the charging od the capacitor 29 is started when no signal exists on the tape any more. Then a TR33 is turned on when the both-terminal potential of the capacitor 29 reaches the threshold level decided by diodes 30 and 31 and the TR33. Then a rapid traverse command is fed to an operation circuit. Thus the recording/reproducing device is automatically set into a rapid traverse mode. Therefore a terminal 49 is set at 0 level, and the TR33 is turned off. When the tape reaches its termination in the rapid traverse mode, the tape driving direction is switched with the output of a tape termination detecting circuit. Then a reproduction command is supplied to the operation circuit, and the recording/reproducing device is automatically set into a reverse reproduction mode.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording and reproducing device equipped with an automatic reversing function that detects the end of a tape and automatically reverses the tape running direction. The purpose of this system is to automatically skip over recorded parts even if there are recorded parts, so that continuous playback without interruption can be performed.

In general, a magnetic recording/playback device equipped with an automatic reversing function is characterized by its ability to automatically and continuously play back audio information recorded on the top and bottom two tracks of a magnetic tape, without turning the tape over. be. When playing back a magnetic tape using such a device, assuming that the magnetic tape was recorded without long gaps, the audio information recorded on the tape will be played back continuously without interruption. , it is possible to take advantage of the features of the device. However, with user-edited magnetic tapes, there are often long blank spaces at the end of the tape depending on the recording source, and when playing back such tapes, the playback of the audio information on one track ends. After that, when the tape running direction is reversed, there is a blank time during which nothing is played back, and the features of the above-mentioned automatic reversing function are not fully utilized.

The present invention overcomes these conventional drawbacks,
If the playback of the audio information ends before the tape reaches the end, the tape is automatically fed forward until it reaches the end, and when the tape reaches the end, the tape running direction is automatically reversed and Shift the device to the playback state and play a continuous page with no interruptions.

In the figure, 1 to 4 go to playback 1. 2
and 3 are for playing the left and right channels when the tape is running in the normal rotation direction. Dos 1 and 4 are on the left when the tape is running in the reverse direction.

Go to right channel playback. Although the outputs of these playback heads are not shown here, they are supplied to a preamplifier 7.8 by a switch 6.6 which is switched by continuous operation of the tape running direction. Semi-fixed resistor 9
, 10 are for adjusting the output level of the line output terminals 13 and 14, and are connected to the semi-fixed resistor 9.10 and the output terminal 13.
．． Line amplifiers 11 and 12 are connected between the lines 14 and 14, respectively.

18 is an amplifier for signal detection, and the left and right channel outputs from the amplifier 7.8 are supplied to the input terminal of the amplifier 18 via resistors 15 and 16 and a semi-fixed resistor 17. . A rectifier circuit 19 rectifies the output signal of the amplifier 18, and is composed of capacitors 20, 23, diodes 20, 22, and a resistor 24. The transistor 25 is operated by the output of the rectifier circuit 19, and has the function of discharging the capacitor 29 of the first time constant circuit 26.

This first time constant circuit 26 includes a resistor 28 . capacitor 2
9. It is composed of diodes 27, 30, 31 and a semi-fixed resistor 61, and the time constant can be changed by the semi-fixed resistor 61. The transistor 33 is operated by the output of the first time constant circuit 26, has a pull-up resistor 32 connected to its collector, and has a terminal 34 connected to a logic-controlled tape running operation circuit (not shown). It is connected to the fast forward operation input terminal. 45 is a second time constant circuit, and a terminal 46 is connected to a "0" circuit for a short time during regeneration operation and running reversal operation.
When the pulse is input, the capacitor 44 is discharged through the diode 43, but when the pulse is no longer present, the resistor 52 is discharged.
The capacitor 44 is charged by this, and later the voltage of the capacitor 44 rises to the threshold voltage determined by the diode 42 and the transistor 41, and the transistor 41 is turned on, and at the same time, the voltage is turned on via the resistor 4o. The transistor 39 is turned off. Next, 47 and 48 are diodes, and the respective connection terminals 49 and 50 are set to the "o" level during fast forwarding and rewinding. The transistor 35 is a transistor connected to turn on via a resistor 36 when the transistor 26 is turned on, and this transistor 35 lights up a light emitting diode 38 via a resistor 37.

The operation of the above embodiment will now be explained.

When a regeneration operation is performed, a "0" pulse is applied to terminal 46 and capacitor 44 is discharged. When the pulse disappears, the capacitor 44 is charged via the resistor 52, but as described above, the transistor 39 operates so as to change from the on state to the off state after a certain period of time after starting the regeneration operation. Then, the capacitor 29 starts to be charged by the resistor 28 and the semi-fixed resistor 51. If there is a signal at Chibuto, amplifier 18. Transistor 2 via rectifier circuit 19
Since the capacitor 5 is turned on, the capacitor 29 is hardly charged. However, when the signal on the tape disappears, the capacitor 29 starts charging, and this capacitor 2
The potentials across 9 are diode 30, 31 and transistor 3.
When the threshold voltage determined in step 3 is reached, the transistor 33 is turned on and a fast-forward command is input to an operation circuit (not shown), so that the device automatically enters a fast-forward state. When the device enters the fast-forward state in this way, the terminal 49 jumps to the "o" level, so the transistor 33 is turned off. Although not shown in the figure, when the tape reaches the end in fast forward mode, the tape running direction is switched by the output of the tape end detection circuit, a playback command is input to the operation circuit, and the device automatically enters the reverse playback state. Even after the reversal operation, the same operation as in the reproduction operation described above is performed. The reason why the terminal 60 is set to the "○" level through the diode 48 during rewinding is because no signal is sent from the amplifier 18 during rewinding. This is to prevent the device from being changed to a fast forward state due to silence detection. It's the second
The time constant circuit 45 is often equipped with a leader tape at the beginning of the tape, and in this case, it takes time from the start of the playback operation until the signal on the tape is output, This is to prevent malfunctions during signal detection, and if there is no signal during signal detection, the first
After the time determined by the time constant circuit 26, the fast forward operation is started. Light emitting diode 38 is tape
If the transistor 25 is turned on due to - noise, normal detection operation becomes impossible, so whether or not the detection is normal is checked based on the operating state of the transistor 25.

Further, the semi-fixed resistor 17 is used to adjust the gain of the amplifier 18 to make the detection level normal when the transistor 25 is turned on due to the noise level of the tape. Unfortunately, the semi-fixed resistor 51 is used to set a time longer than the interval between songs so that the above-mentioned silence detection operation does not occur in the unrecorded portion between the songs on the tape.

As explained above, according to the magnetic recording and reproducing device of the present invention, the usability of the magnetic recording and reproducing device with an automatic reversing function is improved, and the user does not have to perform unnecessary operations, and the effect is great. It is what it is.

[Brief explanation of drawings]

The figure is a circuit diagram of a main part of an embodiment of the present invention.05.6...
...Tape running direction selection switch, 19...
- Rectifier circuit, 26...First time constant circuit, 45
The...first constant circuit. Name of agent: Patent attorney Toshio Nakao and one other person

Claims (4)

[Claims] (1) When the end of the tape is detected in the playback mode, the tape running direction is reversed and the playback mode continues; when the tape end is detected in the fast forward or rewind mode, the tape running direction is reversed and the tape is played back. A magnetic recording/reproducing device configured to shift to an operating state, which includes an amplifier that amplifies the playback signal from the tape, a rectifier circuit that rectifies the output signal of this amplifier, and an operating state that is controlled by the output of the rectifier circuit. a time constant circuit that is reset by the operation of the first switching means; and a second switching means whose operating state is controlled by the output of the time constant circuit. When there is a reproduction signal from the tape, the first switching means is activated, the time constant circuit is reset, and the second switching means is held in an inoperative state. However, when the reproduction signal from the tape disappears, the first switching means is activated. becomes inoperative, the second switching means is activated, and the second switching means is activated.
A magnetic recording/reproducing device configured such that the device automatically enters a fast-forward state by the operation of a switching means. (2) The magnetic recording and reproducing apparatus according to claim 1, wherein the time constant circuit is configured to become operable after a predetermined period of time has elapsed after the start of the reproducing operation or the start of the reversing operation. (3) The magnetic recording and reproducing apparatus according to claim 1 or 2, which is configured to display the operating state of the first switching means. (4) Claim 1 or 2 in which at least one of the time constants of the gain 2 time constant circuit of the amplifier is made variable.
The magnetic recording and reproducing device described in .