JPS6242341B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an auto-reverse device for a tape recorder that automatically drives the magnetic tape to run in the opposite direction when the magnetic tape runs in one direction and reaches near the end. Regarding.

Conventional auto-reversing devices for tape recorders have been proposed in various configurations, some of which include optical transmission between a leader tape connected to the start and end of a magnetic tape and the magnetic tape. A device that obtains a reverse signal by detecting the difference in index or light reflectance.

A conductive sensing foil is pasted near the end of the magnetic tape and detected by a contact pole, etc. to obtain a reverse signal.

When the end of the tape is fixed to the reel hub, such as with a cassette tape, it detects changes in tape tension, stops rotating the reel, etc.
The one that gets the reverse signal.

etc. are generally known. However, in all of these, the tape run is reversed regardless of the recorded content, and the recording is interrupted during this reversal operation, so the music may be interrupted in the middle, causing discomfort to the listener, or important words in the conversation may be difficult to hear. However, there were some shortcomings that could impede understanding of the content. Particularly for listeners who pursue high-fidelity (so-called HiFi) reproduction of music, the above-mentioned interruption during music reproduction is considered a fatal flaw.

SUMMARY OF THE INVENTION An object of the present invention is to provide an auto-reversing device for a tape recorder that can eliminate such drawbacks and automatically perform back-and-forth recording without interrupting recorded content.

An auto-reverse device for a tape recorder automatically reverses the running direction of the magnetic tape so that signals can be recorded or played back in both directions. a signal detecting means for detecting the amount of tape remaining on the supply reel based on the rotation period of the tape reel; and outputs of the signal detecting means and the remaining tape detecting means are supplied; logic means for outputting a reverse signal only when the remaining amount is below a predetermined value and the minimum signal level duration is above a predetermined value; means for reversing the running direction of the magnetic tape in response to the reverse signal; The apparatus is characterized in that it is configured to include means for reversing the running direction of the magnetic tape in response to a signal.

Here, the lowest level of the recording/playback signal refers to the level when there is no more sound to be recorded, such as when there is no sound between music songs or when the speaker changes in a lecture or conversation. . Further, the remaining amount of tape is the length of the magnetic tape remaining on the supply reel side, and is also the time (remaining time) that can be recorded from the current time to the end of the magnetic tape. A reverse signal is obtained based on the correlation between the duration of these lowest signal levels and the remaining amount of tape. Various combinations of this correlation are possible, but the simplest method is to AND (logical product) of each condition. That is, a detecting means outputs "1" when the minimum signal level continues for a set time (for example, set to about 3 seconds) or more, and a detection means that outputs "1" when the above-mentioned minimum signal level lasts for a set time or more (for example, set to about 3 minutes), and a detecting means that outputs "1" when the remaining tape amount is set to a set value (for example, the remaining time is set to about 3 minutes). ), the outputs of these detection means may be sent to an AND circuit, and the output of this AND circuit may be used as a reverse signal. In addition, the setting value of the minimum signal level duration may be made smaller as the remaining tape capacity decreases.

According to the configuration described above, the running direction of the magnetic tape is automatically reversed when the remaining amount of tape becomes low and the music song ends and there is no sound, so the recording content can be recorded without interruption. , it is possible to record and play back and forth continuously. Therefore, even when recording while the user is away, the recording time can be twice as long as in the past.

Hereinafter, preferred embodiments of the present invention will be described.
This will be explained with reference to the drawings.

In FIG. 1, a cassette tape 1 has two reels 2, 3 and a magnetic tape 4 wound around these reels. The magnetic tape 4 is driven to run by two sets of capstans 5 and 6 and pinch rollers 7 and 8. An erasing head 9, a recording/playback head 10, and an erasing head 11 are arranged in this order between the pinch rollers 7 and 8, and the two erasing heads 9 and 11 move according to the running direction of the magnetic tape 4 during recording. Therefore, only one of them performs the erase operation.
For example, when the magnetic tape 4 runs in the direction of the arrow in FIG. 1, only the erasing head 9 performs the erasing operation.

The recording signal amplification system 12 amplifies a microphone signal input to an input terminal 13 via a microphone amplifier 14 and a line amplifier 15, and further sends it to the recording/reproducing head 10 via a recording equalizer amplifier 16. In addition, in the case of a signal from a tuner or other tape deck, input terminal 17
The signal is directly input to the line amplifier 15 via the line amplifier 15.

Next, the auto-reverse device 20 includes a signal level detection section 21 and a remaining amount detection section 22 for the magnetic tape 4, and their detection outputs are sent to an AND circuit 23.
is being sent to. First, the signal level detection section 21
As described above, this detects the lowest signal level and its duration corresponding to a silent state. Regarding the recording signal, a part of the output of the line amplifier 15 of the recording signal amplification system 12 is detected by the detection amplifier 24.
is taken out via the diode 25, and rectified by the diode 25.
It is sent to an RC parallel circuit of a capacitor 26 and a resistor 27. This RC parallel circuit consists of diode 2
The AC component of the audio signal rectified by step 5 is removed, and the DC component voltage, which is approximately proportional to the volume, is sent to the next stage inverter 2.
8. In this case, in the silent state,
Since the current supplied from the detection amplifier 24 to the capacitor 26 via the diode 25 becomes almost 0,
The accumulated charge in the capacitor 26 is discharged via the resistor 27, and the output voltage of the RC parallel circuit decreases. The inverter 23 performs a switching operation and sends a signal "1" to the AND circuit 23 when the output voltage of this RC parallel circuit falls below a certain value. Here, the time constant of the RC parallel circuit and the switching voltage value of the inverter 28 determine the duration of the silent state (ie, the lowest signal level) for the inverter 28 to perform the switching operation.

Next, the tape remaining amount detection unit 22 of the auto-reverse device 20 detects the remaining amount of the magnetic tape 4, that is, when the tape running direction is in the direction of the arrow in FIG.
This detects the length of the magnetic tape 4 remaining unwound or the time required to record and reproduce this length. The remaining amount of tape is determined by detecting the rotation period of at least one of the reels 2 and 3. This is because the winding diameter is determined by the amount of tape wound around each reel 2, 3, and the rotation period of each reel 2, 3 is determined by this winding diameter.

For this reason, in the tape remaining amount detection section 22, the rotation period of the reel 2 is first detected by the rotation detector 29. This rotation detector 29 can take various configurations, but a typical configuration is such that a rotating body such as a disk or cylinder is provided on the drive shaft of the reel 2, and the rotation of this rotating body is detected and converted into an electric signal. be. Specifically, there are those in which S and N magnetic poles are magnetized at equal intervals around the periphery of a rotating disk, and these magnetic poles are detected using a saturable inductance, a Hall element, a magnetoresistive element, etc., and those that are connected to the rotation axis of a rotating disk. A device may be used in which slits or through holes are provided at equal intervals on concentric circles, and the slits or through holes are detected by a pair of a light emitting element and a light receiving element arranged to sandwich the rotating disk. From the rotation detector 29 having such a configuration, a rotation detection pulse having a period t proportional to the rotation period T of the reel 2 is obtained. The relationship between these periods T and t is, for example, T=nt, where n is the number of the magnetic poles, through holes, etc. provided on the rotating disk. This rotation detection pulse with period t is transmitted to the frequency divider 30
This results in a rotation detection pulse with period T, which is sent to the period discrimination circuit 31. The cycle discrimination circuit 31 discriminates whether the cycle of the input pulse is large or small (long or short) with respect to a preset reference cycle, outputs a signal of "0" or "1", and sends this to the AND circuit 23. There is.
If, for example, the rotation period of the reel 2 when there is enough remaining tape to record only 3 minutes is selected as the reference period, the output of the period discrimination circuit 31 becomes "0" 3 minutes before the tape reaches its end. to "1".

Here, a specific example of the structure of the period discrimination circuit 31 will be explained with reference to FIG. 2. In FIG. 2, an input terminal 32 to which a rotation detection pulse of period T is applied is connected to the base of a transistor 33. In FIG. The collector of this transistor 33 consists of a resistor 34 and a capacitor 35.
An RC circuit is connected, and the base of a transistor 36 is further connected to this collector. The emitter of this transistor 36 is the transistor 37
It is commonly connected with the emitter of , forming a so-called current switch circuit. The collector of the output transistor 37 of this current switch circuit is
Connected to the base of transistor 38. An RC parallel circuit consisting of a resistor 39 and a capacitor 40 is connected to the emitter of this transistor 38, and the base of a transistor 41 is connected to this emitter. The collector of this transistor 41 is connected to the output terminal 42 of the period discrimination circuit 31, and this output terminal 42 is connected to the AND circuit 23.
It is connected to the.

The operation of the period discrimination circuit 31 having the above configuration will be explained with reference to FIG. Here, FIG. 3A shows that when the period T of the rotation detection pulse is long,
Figure 3B shows the case where the period T is short, and the waveforms (a) to (d) for these A and B represent the voltage waveforms appearing at each point a to d in Figure 2 in each case. This is a time chart.

First, if the period T of the rotation detection pulse (a) applied to the input terminal 32 is long as shown in FIG. 35 is charged for a longer period of time, signal (b) of FIG. 3A is applied to the base of transistor 36. transistor 3
Since the current switch composed of 6 and 37 discriminates the level of the above signal (b) at a constant level L,
The collector output signal of the transistor 37 is shown in Fig. 3A.
(c). This signal (c) is smoothed by the capacitor 40 through the transistor 38, and becomes a relatively high level signal as shown in the signal (d) in FIG. 3A.

On the other hand, as shown in signal (a) in Figure 3B, the period T
If is short, the OFF time of the transistor 33 is shortened, so the charging time for the capacitor 35 is shortened, and a signal like that shown in (b) is applied to the base of the transistor 36. Therefore, the collector output of transistor 36 is
The signal becomes signal (c) in Figure B, the pulse width becomes shorter, and the average level of the smoothed signal (d) becomes lower.

In this way, the signal (d) applied to the base of the transistor 41 decreases as the rotation period T becomes shorter. Transistor 41 receives this signal (d)
A switching operation is performed at the time when s falls below a certain level s, and the output signal of the output terminal 42 changes from "0" to "1". The above-mentioned constant level s is determined according to the remaining amount of tape to be detected,
For example, if it is desired to detect that the remaining time has reached 3 minutes, the level s may be set equal to the level of the signal d corresponding to the rotation period T at this time.

Various other configurations are known for the configuration of the period discrimination circuit 31. For example, means for generating pulses with a constant period sufficiently shorter than the rotation period T is provided, and the period discrimination circuit 31 is provided with means for generating pulses with a constant period that is sufficiently shorter than the rotation period T. A configuration that counts the number of pulses is also often used. In this case, as the period T becomes shorter, the count value also decreases, and when this count value falls below a certain value, the signal "1" may be output. Of course, this constant count value is also determined depending on the remaining amount of tape to be detected. Such period discrimination is particularly effective in the case of tape recorders equipped with microprocessors, which have become widely used in recent years.

As described above, when the lowest signal level corresponding to a silent state continues for a certain period of time (for example, about 3 seconds) or more, the signal level detection section 21 performs a switching operation to send a signal "1" to the AND circuit 23, and The remaining tape amount detecting section 22 performs a switching operation to output a signal "1" to the AND circuit 23 when the remaining recordable time falls below a certain value (for example, about 3 minutes).
send to When all of these two input signals become "1", the AND circuit 23 outputs an output signal "1" as a reverse command signal to the reverse drive device 43.
send to At this time, the reverse drive device 43 reverses the actual tape running direction by reversing a motor (not shown) or operating a power transmission mechanism such as an idler, and at the same time reverses the actual tape running direction. By switching the recording and reproducing track of the recording and reproducing head 10, so-called reverse recording and reproducing is performed.

Here, the signal level detection unit 21 does not perform a switching operation during a short pause time (usually 1 second or less) due to a rest symbol included in one piece of music,
The switching operation is performed only when a certain period of time (for example, about 3 seconds) of silence continues after the song ends. Further, the tape remaining amount detection unit 22 does not perform a switching operation when the time that can be recorded with the remaining tape amount is longer than approximately one music song (for example, about 3 minutes), and the switching operation is near the limit where one song cannot be recorded. Switching operates when there is enough remaining tape. Therefore, when a music song ends and there is not enough tape remaining to record one more song, the reverse operation is automatically performed.

Therefore, reverse recording can be automatically performed without interrupting the music while the user is away, and recording when the user is away can be performed with peace of mind. Comparing this with conventional auto-reverse devices, firstly, it prevents the inconvenience of reversing the tape in the middle of the recorded content, such as during the performance of a music song, when there is no operator present, such as when recording while the user is away. . Furthermore, even when an operator is present to manually reverse the tape, conventional auto-reversing devices check the tape counter and the amount of tape remaining on the supply reel to determine whether one more song can be recorded. When the tape is finished, the tape must be reversed quickly and manually, and when the remaining amount of tape is low, the user must wait near the tape recorder, concentrate on the tape recorder, and sometimes put his finger on the reverse operation button. However, since all these preparations and operations are no longer necessary, you can enjoy good recordings while enjoying music or doing other things.

In the above, the signal level detecting section 21 detects that the duration of the lowest signal level exceeds a preset fixed time, and the remaining tape amount detecting section 22 detects that the remaining tape amount is below a preset fixed value. This was an example in which a reverse signal is obtained by detecting each signal individually and ANDing them. The second shown in
As in the embodiment, a configuration may be adopted in which the duration of the minimum signal level required to obtain a reverse signal is shortened as the remaining tape amount decreases.

That is, in the second embodiment shown in FIG. 4, the signal level detector 21' and the remaining tape amount detector 2
2' is the signal level detection section 2 of the first embodiment.
1 and the tape remaining amount detection section 22, and the same parts are given the same reference numerals and a description thereof will be omitted. Here, the inverter 28 which is the output circuit of each detection unit 21 and 22 of the first embodiment
The output circuits 28' and 31' of the second embodiment each output a digital signal based on a switching operation, whereas the output circuits 28' and 31' of the second embodiment output signals that are approximately linear with the duration of the lowest signal level and the remaining amount of tape. The circuit configuration and circuit constants are designed to output related analog signals. In this case, output circuit 2
The level of the output of the output circuit 8' increases as the duration of the lowest signal level corresponding to a silent state increases, and the level of the output of the output circuit 31' decreases as the remaining amount of tape decreases. These output circuits 2
The outputs from 8' and 31' are sent to the respective bases of transistors 44 and 45 forming a current switch circuit. Therefore, as the remaining amount of tape decreases, the base potential of transistor 45 decreases, and the duration required for switching the current switch circuit becomes shorter. Furthermore, transistor 4
Diode 4 connected in series to the base of 4
6, this base potential is clipped so that it does not exceed a certain level, and when the remaining amount of tape approaches 0, the base potential of the transistor 45 becomes below the clip potential, and the recording signal level is kept at the lowest level. The current switch circuit is forced into switching operation even if it does not occur.

The output of this current switch circuit is transmitted through a drive circuit composed of transistors 47, 48, etc.
It is sent to the reverse drive device 43. This reverse drive device 43 performs actual reverse operations such as tape running reversal and head switching as described above.

Therefore, according to this second embodiment, the switching operation is enabled from the time when the remaining amount of tape (remaining time) reaches about 5 minutes, and when the remaining time is 5 minutes, there is no sound for about 10 seconds, for example. When it lasts, the current switch circuit is operated, and as the remaining time approaches 3 minutes, 1 minute, and 30 seconds, the duration is shortened to 3 seconds, 2 seconds, and 1 second, and then the remaining time approaches 0 seconds. Now, it is possible to control the reverse operation even during the middle of a song. Note that the relationship between the remaining time and the duration described above is an example, and any other combination is possible.

In this second embodiment, of course, the effects of the first embodiment can be obtained, but by appropriately combining the remaining tape amount and the duration of the lowest signal level, even finer and better automatic Reverse operation is possible.

Note that the present invention is not limited to the above two embodiments; for example, if the auto-reverse operation is configured to operate under the same conditions not only during recording but also during playback, the remaining tape amount can be set to the same level as the recording reverse position. Since it reverses at the desired position, optimal auto-reverse playback can be performed at appropriate intervals even in silence.
Furthermore, in the case of a tape recorder with a built-in timer, it is possible to have a configuration in which the remaining time of the music program obtained from the timer is compared with the remaining tape amount (remaining time).

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention, FIG. 1 is a block circuit diagram showing the whole, and FIG.
The figure is a circuit diagram showing a specific circuit example of the period discrimination circuit 31 in Figure 1, and (a) to (d) in Figures A and B are time points showing voltage outputs at each point a to d in Figure 2. Chaat, 4th
The figure is a circuit diagram showing the main parts of the second embodiment. 1...Cassette tape, 2, 3...Reel, 4
...Magnetic tape, 20...Auto reverse device,
21...Signal level detection section, 22...Tape remaining amount detection section.

Claims (1)

[Claims] 1. In an auto-reverse device for a tape recorder that automatically reverses the running direction of a magnetic tape and records or plays back signals in both directions, the lowest level of the recording or playback signal and its duration are a signal detecting means for detecting the remaining amount of tape on the supply reel based on the rotation period of the tape reel; and outputs of the signal detecting means and the remaining tape detecting means are supplied to detect the remaining amount of tape on the supply reel based on the rotation period of the tape reel. comprising: logical means for outputting a reverse signal only when the minimum signal level duration is equal to or less than a predetermined value; and means for reversing the running direction of the magnetic tape in response to the reverse signal. An auto-reverse device for a tape recorder, characterized in that: