JPH03250446A - Back spacing circuit for tape recorder - Google Patents

Abstract

PURPOSE:To fix the length of a magnetic tape to be rewound even if its winding diameter is changed by measuring the pulse width of a pulse signal obtained at the time of reproducing operation and counting up the number of pulses based upon the pulse width to determine the rewinding operation time. CONSTITUTION:In the reproducing operation state, a pulse signal outputted from a pulse signal generating circuit 25 is inputted to a pulse width measuring circuit 24 and the pulse width P is measured. A user sets up the length of the magnetic tape to be rewound in a rewinding length setting circuit 19 as the time T required for reproducing operation by the 1st and 2nd time setting switches 20, 21. When the rewinding operation of the magnetic tape is started, a pulse number counting circuit 26 counts up the number of pulses outputted from the circuit 25, and when the number N of pulses satisfied an equation N=A(1/PXT) (A is a constant), the output signal of a rewinding output terminal 17 is inverted to the 'L' level and a tape recorder is turned to a stopped state. Thus, the length of the magnetic tape to be rewound is fixed even if the winding diameter of the tape is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tape recorder having a backspace function that rewinds a magnetic tape a little when a stop operation is performed from a playback state and then switches to a stop state.

(b) In a conventional tape recorder, when the magnetic tape is stopped in the middle of reproducing information recorded on the magnetic tape and then the magnetic tape is driven again to continue reproducing the information, Since it is easier to understand the continuation of a sentence by replaying some of the previously played information before replaying it, a tape recorder called a dictating transcriber machine, which is used especially with a typewriter, can be stopped before it is in playback mode. It generally has a function called backspace, which rewinds the magnetic tape a little and then stops it. A technique for performing such a backspace operation is disclosed in, for example, Japanese Utility Model Publication No. 57-44501.

(8) Problems to be Solved by the Invention The above-mentioned publication describes a technique in which, when a stop operation is performed during a playback operation, the magnetic tape is rewound and then stopped.

The rewinding operation time in this technology is set by the charging voltage of the capacitor, but even if the rewinding operation time is the same, the length of the magnetic tape rewound during that time will vary depending on the winding diameter of the magnetic tape. There will be a big difference.

When the rewind length of the magnetic tape changes, the length of the signal that is played back changes, so it is necessary to adjust the rewind operation time near the beginning of the magnetic tape and near the end of the magnetic tape. It is inconvenient. The present invention aims to provide a backspace circuit that is improved in this respect.

(d) Means for Solving the Problems The backspace circuit of the present invention includes a pulse signal generation circuit that generates a pulse signal corresponding to the rotational speed of the reel shaft;
a pulse width measurement circuit that measures the pulse width of the pulse signal output from the pulse signal generation circuit during reproduction operation; and a pulse width measurement circuit that receives the pulse signal output from the pulse signal generation circuit and counts the number of pulses. It is composed of a number counting circuit, a rewind length setting circuit that sets the rewind length by the backspace operation, and a display that displays the rewind length by the rewind length setting circuit in terms of the time during the playback operation. .

(f) Function The present invention determines the rewinding operation time by counting the number of pulses based on the pulse width of the pulse signal obtained from the pulse signal generating circuit during the reproducing operation, and determines the rewinding operation time of the magnetic tape that can be rewound during the backspace operation. The length of the magnetic tape is made the same even if the winding diameter of the magnetic tape is different, and the length of the magnetic tape is displayed in terms of the time during the reproduction operation.

(f) Embodiment The illustrated circuit is an embodiment of the backspace circuit of the present invention. In the figure, (1) is a rotating reflector that rotates in conjunction with the reel axis, (2) is a photocoupler consisting of a light emitting diode (3) and a phototransistor (4), and the rotating reflector is in a rotating state. The phototransistor (4) is configured to alternate between a conductive state and a non-conductive state when the phototransistor (4) is in a conductive state and a non-conductive state. <5) is a switching transistor whose emitter is connected to a power supply and whose flipter is grounded via a resistor (6).
Its base is connected to the emitter of the phototransistor (4). (7), (8), (9)
and (10) are playback operation switches, fast-forward operation switches, rewind operation switches, and stop operation switches that are pressed and closed during playback, fast forward, rewind, and stop operations, respectively; and <11) are the respective operations described above. Switch (7), (8)
.

(9) A control circuit that controls each operation of the tape reflex based on the signal input by closing (10);
(12) enters an open operating state in which an H (high) level drive signal is output to the playback output terminal (13) provided in the control circuit (11), and also puts the tape recorder into a playback operating state. The playback switching circuit (14) enters an open operating state in which an H-level drive signal is output to the fast-forward output terminal (15) provided in the control circuit (11), and causes the tape recorder to perform fast-forward operation. A fast-forwarding switching circuit (16) for changing the control circuit (1)
1) is a rewinding switching circuit which puts the tape recorder into a rewinding operation state when the tape recorder enters an open operating state in which an H level drive signal is output to the rewinding output terminal (17) provided in the rewinding output terminal (17) provided in the rewinding output terminal (17). Reference numeral (18) is a selection switch for selecting operation/non-operation of the backspace operation, and is configured to be closed during the backspace operation.

(19) is a rewind length setting circuit for setting the rewind length of the magnetic tape during backspace operation, and is configured to set the rewind length in accordance with the time required for playback during playback operation. There is. <20) is a first time setting switch that is operated to set the rewind length time and increases the rewind length time by, for example, 0.5 seconds each time it is pressed and closed; Similarly, it is a second time setting switch that is operated to set the rewind length time and decreases the rewind length time by, for example, 0.5 seconds each time it is pressed and closed. (22> is a numeric display, (2
3) is a display drive circuit that causes the number display (22) to display the time set by the rewind length setting circuit (19). (24) indicates that when the tape recorder is in the playback operation state, a pulse signal output from the pulse signal generating circuit (25) composed of the photocoupler (2) and the switching transistor (5), etc. is input, and the pulse signal is A pulse width measurement circuit (26) measures the pulse width of a signal, and (26) is a pulse width measurement circuit that measures the pulse width of a signal.
5) A pulse number counting circuit which receives the pulse signal outputted from 5) and counts the number of pulses. In such a circuit configuration, when the tape recorder is in a backspace operation state by closing the selection switch (18) and a stop operation is performed from the playback operation state, the output signal of the playback output terminal (13) goes to H level. At the same time, the rewinding output terminal (17
) is configured to output an H level signal for the time required to rewind the magnetic tape by the length set by the rewind length setting circuit (19). The time during which an H level signal is output to the rewinding output terminal (17) for performing the rewinding operation for the backspace operation is determined as follows. The rewind length set by the rewind length setting circuit (19), that is, the time required for the reproduction operation, is T, the pulse width measured by the pulse width measurement circuit (24) is P, and the magnetic tape of the set length is If the number of pulses required to unwind is N, then the following relational expression holds true: N=A('XT) where A is a constant. Here, the value of N is rounded up to the nearest integer, and is equal to the number of N in 7/<Russ counting circuit 26)
The control circuit (11) is configured such that the output signal of the rewinding output terminal (17) becomes L level rather than H level when the rewinding output terminal (17) is counted.The backspace circuit of the present invention is configured as described above. Next, the operation of such a circuit will be explained.

When the selection switch (18) is in an open state, that is, in a state in which no hack space operation is performed, press and close the playback operation switch (7), fast forward operation switch (8), and rewind operation switch (9). The control circuit (1
1), each output terminal (13), (15
>, an H level signal is output to (17), and the playback switching circuit (12) and fast forwarding switching circuit (14)
and the rewind switching circuit (16>) are activated to bring the tape recorder into each operating state.Furthermore, when the stop operation switch <10> is pressed and closed when the tape recorder is in each operating state, each Output terminal (13),
The output signals of (15) and (17) are at L level, and each switching circuit (12) and (14) is in an operating state.
.

<16) becomes inoperative, so the tape recorder is returned to the stopped state. When the tape recorder is in each operating state, the rotating reflector (
1) rotates, light from the light emitting diode (3) that constitutes the photocoupler (2) is transmitted to the phototransistor (
4) Intermittent irradiation is completed. As a result, the phototransistor (4) repeatedly conducts a conductive operation and a non-conductive operation, and as the phototransistor (4) reverses its operation, the switching transistor (5) also repeatedly performs a conductive operation and a non-conductive operation. Therefore, a pulse signal is output from the collector of the switching transistor (5), and the pulse width measuring circuit (24) and the pulse number counting circuit (26) are output as a pulse signal that can be output from the pulse signal generating circuit (25).
).

The normal operation of the tape recorder is performed as described above, but the backspace operation will be explained next. Such a backspace operation is performed when a stop operation is performed from a reproducing operation state while the selection switch (18) is in a closed state.

A pulse signal output from the pulse signal generation circuit (25) during the reproduction operation state is input to the pulse width measurement circuit (24), and the pulse width P is measured by the pulse width measurement circuit (24). The user sets the length of the magnetic tape to be rewound by the backspace operation using the first time setting switch (20) and the second time setting switch (21).
This set value is set as the playback time T during the playback operation. The time set in the rewind length setting circuit (19) is determined by the display drive operation of the display drive circuit (23) on the numeric display (22).
) can be displayed.

Therefore, the user can recognize the length of the magnetic tape rewound by the backspace operation based on the playback operation time. When the user presses and closes the stop operation switch (10) in such a reproducing operation state, the output signal of the reproducing output terminal (13) is inverted from the H level to the L level and the rewinding output terminal The output signal of (17) is inverted from L level to H level. As a result, the tape recorder is put into the rewinding state after being released from the reproducing state, and the rewinding operation of the magnetic tape can be started. When the rewinding operation of the magnetic tape is started, the pulse number counting circuit (26) counts the number of pulse signals output from the pulse signal generating circuit (25) in association with the rewinding operation. As the magnetic tape is rewinded, when the pulse count circuit (26) reaches a value that satisfies the total, the output signal of the rewind output terminal (17) is inverted from the H level to the L level, and the tape recorder Forced to stop. When the tape recorder that has been switched to the stopped state is operated in this way, the playback operation state is configured and the playback operation of the signals that have been completely recorded on the magnetic tape is started, but the playback operation is stopped within the first hour. The signal received will be the same as the signal heard in the previous playback operation. Therefore,
The user listens to the signal reproduced from the magnetic tape again from the part he listened to last time, and can easily understand the contents of the text and the like. If the stop operation is performed during the playback operation state, the backspace operation described above will be performed, but even if the winding diameter of the magnetic tape changes, the time T set by the rewind length setting circuit (19) will not change. If they are the same, the length of the magnetic tape to be rewound becomes the same by changing the rewinding operation time.

Therefore, even if a backspace operation is performed while playing back a signal recorded near the folding position at the beginning or end of the magnetic tape, the length of the magnetic tape rewound will remain the same. , very convenient.

In this embodiment, the present invention is configured by a control circuit (11), a pulse width measuring circuit (24), a pulse number counting circuit (26), etc., but it can also be configured using a microcomputer. In addition, the pulse width measurement circuit (24
) does not necessarily have to be performed continuously, but can also be performed at predetermined intervals.

Although the pulse signal generating circuit (25) is configured by a photocoupler (2), a switching transistor (5), etc., it is of course possible to use other circuit configurations. Also, the rewind length setting circuit (1) is displayed on the numeric display (22).
Although the time set by 9> is displayed, it is also possible to display the running distance of the magnetic tape.

(G) Effects of the Invention The backspace circuit of the present invention measures the pulse width of a pulse signal obtained from a pulse signal generation circuit during a reproducing operation, and counts the number of pulses based on the pulse width as a rewind operation clock. The feature is that the rewinding operation time is determined, and by doing this, the length of the magnetic tape that is unwound during the backspace operation can be made the same even if the winding diameter of the magnetic tape is different. can.

Furthermore, in the present invention, the length of the magnetic tape rewound during the backspace operation is displayed by the time during the playback operation, so the user can easily recognize the time when the magnetic tape will be played back again by the backspace operation. Therefore, the present invention is most suitable as a backspace circuit for a tape recorder.

[Brief explanation of drawings]

The illustrated circuit is a packspace circuit car embodiment of the present invention. Explanation of main drawing numbers (1)...Rotating reflector, (2)...Photocoupler (11)...Control circuit, (12)...Reproduction switching circuit, (14)... Rapid forward switching circuit, <16
)...Rewinding switching circuit, (19)...Rewinding length setting circuit, (22)...Numeric display, <23)
...Display drive circuit, (24)...Pulse width measurement circuit, (25)...Pulse signal generation circuit, (26)...Pulse number counting circuit.

Claims (1)

[Claims] (1) A pulse signal that generates a pulse signal corresponding to the rotational speed of the reel shaft in a tape recorder equipped with a backspace function that rewinds the magnetic tape a little when the stop operation is performed from the playback state and then switches to the stop state. a pulse width measurement circuit that measures the pulse width of a pulse signal output from the pulse signal generation circuit during a reproducing operation; and a pulse width measurement circuit that receives the pulse signal output from the pulse signal generation circuit and the number of pulses. a rewind length setting circuit that sets the rewind length by the backspace operation, and a display that displays the rewind length by the rewind length setting circuit in terms of the time during the playback operation. The rewind operation time corresponding to the length set by the rewind length setting circuit is determined by counting the number of pulses based on the pulse width measured by the pulse width measurement circuit by the pulse number counting circuit. A backspace circuit for a tape recorder, characterized in that it is configured to do so.