JPS6053365B2 - Magnetic recording and reproducing device for audio signals - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording and reproducing apparatus for audio signals using an endless tape.

Among devices that record and playback audio signals, cassette tape recorders have become rapidly popular, and because of their ease of operation, they can be used not only for recording and playing FM broadcasts, but also for copying the contents of vinyl records onto cassette tapes. It is becoming increasingly common to use tape recorders for playback.

Particularly in the case of short single discs, this method is very convenient because, once transferred to a cassette tape, a large number of songs can be played back consecutively without frequent performance operations. With a cassette tape recorder, especially a regular two-reel type, when you want to select and play a desired song from among the many songs recorded on the tape, you have to fast-forward the tape to find the recording position of that song. , it required complicated operations such as rewinding and rewinding, which was time-consuming.
On the other hand, endless tape cassettes are often used in car stereos.

This cassette is an endless tape that runs in a fixed direction, with multiple tracks recording audio signals arranged in the width direction (in the case of stereo, multiples of 2).
During reproduction, by moving the head one pitch in the tape width direction each time the tape runs one round, signals on all tracks can be reproduced almost continuously. However, the recording method for conventional audio endless tape cassettes is to run the tape at a speed of about 9.5 TrL/SeC, similar to the 2-reel type, and record high frequency bias in the key without any change. In order to ensure the signal-to-noise ratio, the track width cannot be made too narrow. Therefore, the number of tracks on the tape is about 8, and the track pitch is about 0.8 Twt. In addition, in the case of popular music with this cassette, each song is around 3 minutes long,
Since approximately 3 to 4 songs are recorded per track, a track can be selected by manually moving the head as appropriate during playback, but it is possible to select a desired song from among the several songs on one track from the beginning at any time. Making choices is difficult and time consuming. This invention was made in view of the above-mentioned problems, and its purpose is to enable high-quality recording and playback of audio signals, and to select a desired unit from among many already recorded audio signals at the time of playback. To provide a magnetic recording and reproducing device that can quickly select and reproduce a signal (for example, a signal corresponding to a desired song when the content is music).

This invention allows endless magnetic tape, which is a recording medium, to be
．． Basically, the tape is run at a high speed of 7 to 37 TL/SeC, and audio signals are recorded on the tape by a magnetic head that can move in steps in the width direction of the tape. To record an audio signal for one song as one or more tracks on a tape.

During playback, this audio signal is reproduced and demodulated via a magnetic head, but if the head is moved appropriately in the tape width direction to select a track, the same track can contain other tracks. Since the audio signal is not recorded, the audio signal of the desired song can be selected and played back in a short time. The present invention will be explained in detail below with reference to Examples.

FIG. 1 shows the configuration of an endless tape running mechanism, a magnetic head, and its moving mechanism in a recording/reproducing apparatus according to an embodiment of the present invention. This diagram. 1 is an endless magnetic tape (hereinafter simply referred to as tape),
It is wound around the outer periphery of a fixed reel 2 formed in an annular shape as indicated by 1''.The reel 2 has a slit 3 formed in a part thereof that communicates both the inner and outer circumferences, and the winding portion on the reel 2・A 1" tape 1 is pulled out from the innermost circumference of the winding part 1" through this slit 3 to the inside of the reel 2 while being guided by a guide 4, and then guided by a pair of head facing guides 5 and 6 to be magnetically It comes into sliding contact with the head 7. Reference numeral 8 denotes a head moving mechanism for moving the head 7 in a stepwise manner in the width direction of the tape 1.

After the tape 1 comes into sliding contact with the head 7, it is guided between a capstan 9 and a pinch roller 10, which constitute a tape drive mechanism. The capstan 9 is rotationally driven in the direction shown by arrow A by a capstan motor (not shown), and the pinch roller 10 is also rotated in the direction shown by arrow B, so that the tape 1 is driven to run in the direction shown by arrow C. It's a matter of fact. The tape 1 that has passed between the capstan 9 and the pinch roller 10 is regulated by the guides 11 and 12 to form an appropriate slack, and is further regulated by the guides 13 and 14.
It is guided over the reel 2 and the winding section 1'', and is wound around the outermost periphery of the winding section 1''. In addition, 15
16 is a lower roller that supports the lower surface of the winding part 1'', and 16 is a board that supports the entire device. are selected as such.

When the tape 1 is run at such a high speed, the recordable frequency band on the tape 1 is widened, so that modulation recording such as frequency modulation that requires a wide frequency band becomes possible.
That is, in the present invention, the tape 1 is run at the above-described high speed, and then the audio signal is subjected to, for example, frequency modulation and recorded on the tape 1.

According to frequency modulation recording (hereinafter referred to as FM recording), the nonlinearity of the electromagnetic conversion system including the tape 1 and the magnetic head 7 does not cause distortion during recording and reproduction, so there is no need for high frequency bias as in conventional magnetic recording. There isn't. Therefore, compared to high frequency bias recording, 11? This makes it possible to record at shorter wavelengths, and even higher frequencies can be recorded. FM like this
If an audio signal is recorded, the FM modulation index m1
In other words, the S/N can be improved, so even if the track width on tape 1 is made smaller, the required S/N can be easily achieved.
N can be secured.

Therefore, even if the tape width is the same, it is possible to obtain a much larger number of tracks than in the past, and even when the tape 1 is run at high speed as described above, the recording time for the entire tape 1 is sufficient. To give a concrete example, if a carrier wave of 200 KHz is used for FM recording and the maximum frequency deviation is 150 KHz,
The recording signal has a spectrum with a maximum frequency of 350 KHz, but if the tape 1 is run at a speed of about 1771,/Sec, it is easy to record up to this high frequency. In this case, the audio signal to be recorded, for example 10K
Even at Hz, the modulation index m is m=15, and the S/N is improved by about 24 dB, so even if the pitch of the tracks on the tape 1 is about 50 μm, a sufficient S/N of the reproduced signal can be obtained. In this case, tape 1 is 1'2 inches (12.7
Tfr! n) width, approximately 200 tracks can be formed. FIG. 2 shows tracks Tl, T2, . . . on the tape 1 when recording is performed while the head 7 is moved stepwise in the tape width direction by the head moving mechanism 8 every time the tape 1 runs one round. ...Tn is shown.

In addition, D in FIG. 2 indicates the moving area of the head 7, and when recording or reproducing continuously, the head 7 steps in the tape width direction by a distance corresponding to one track pitch in the area D on the tape 1. move in a specific manner. Here, in the conventional endless tape cassette for audio, as mentioned above, audio signals of about 3 to 4 songs are recorded on each track, but with this invention, the audio signal of one song (one unit) is recorded in 1 to 4 songs per track. Record as multiple tracks.

That is, in the present invention, such a recording method is adopted because the running speed of the tape 1 is very fast and therefore the time required for one round running is short. In this case, the recording time per track will be short, but since the track width is small and the number of tracks can be increased by using FM recording, even if one or more tracks are used to record one song, it will still be possible to record a single song using conventional audio. It is possible to record the same number of audio signals as, or more than, an endless tape cassette. For example, if the time required for one round of tape 1 is taken to be about one second, one song of pop songs and other popular music is approximately three minutes long, so it is recorded as approximately 12 tracks.

If there are 200 tracks on tape 1 as in the previous example, there are actually 16 songs (about 5 tracks) on tape 1 as a whole.
The degree can also be recorded. By recording in this way, a desired song can be immediately played back by simply moving the head 6 using the head moving mechanism 7 and selecting a track during playback.

The time required for this track selection is determined by the head moving mechanism 7.
If it is configured with a step motor or the like, it will take 1 to 2 seconds or less. In addition, even when playing a desired song from the beginning, in other words, when searching for the beginning, the available time (access time)
The maximum time required for running tape 1 once is sufficient. This has an extremely large practical effect compared to the conventional 2-reel or endless tape audio tape recorders that require complicated operations and long running times when trying to play a desired song. . In addition, when actually recording popular music, etc., start recording each song a little after the head movement area D (Fig. 2) on tape 1, and also adjust the head movement by performing operations such as fade-out at the end of the song. It is desirable to record slightly before the movement area D.

In this way, by moving the head 7 for song selection only in this area D, if you want to play the next song after playing a certain song, you can automatically do so without having to start playing from the middle of the song. In addition to being able to quickly locate the beginning of a song, especially when playing multiple songs in succession, even if the songs are recorded on separate tracks,
By moving the head 7 up the area D to the track of the next song to be played every time a song ends, it becomes possible to play the songs one after another with almost no blanking time between them. Some specific design examples according to this invention are shown in the following table.

Here, A is an example in which the running time of tape 1 is approximately 3 minutes and one song is recorded on each track. -2r old 2
This is an example of recording one song on each Q track.

In example A and B, the running speed of the tape 1 is relatively slow, so the tape 1 is stopped in the head movement area D, the head 7 is moved and a track is selected, and then the tape 1 is moved.
It is desirable to adopt a method in which the vehicle starts running. on the other hand,
In example C, the running speed of the tape 1 is fast and the running time for one round is short, so there is no need to use such a method. Also, as is clear from the above table, the sound quality (especially S/N) is determined by the running speed of tape 1, and by the way, even in example A, the playback quality equivalent to that of a conventional ordinary cassette tape recorder can be obtained, and in addition, example C As a result, very good playback quality comparable to that of a vinyl record can be obtained. By the way, especially when the content of the audio signal to be handled is music, it is naturally necessary to consider stereo recording and playback.

When recording stereo audio signals, using separate tracks for each of the L and P (left and right) channels, as in the past, increases the amount of tape used, and requires separate heads, modulation, and demodulation circuits. Since two channels are required, it is uneconomical. Therefore, in this invention, by taking advantage of the wide recordable frequency band on tape and the fact that the recording method is modulation recording, stereo audio signals are recorded on a common track using a multiplex modulation method similar to FM broadcast signals. Record.

In other words, the signal format of the FM broadcast signal is currently a stereo composite signal consisting of an L+R main channel signal, an L-R subchannel signal consisting of a carrier-suppressed amplitude modulated wave, and a pilot signal for demodulation, as shown in Figure 3. ．．
The main carrier wave is frequency modulated by the signal. In the present invention, a stereo audio signal is multiplex modulated and recorded in a similar signal format. Figures 4 and 5 show stereo
An example of the configuration of an electronic circuit used when recording and reproducing audio signals is shown.

In all of the examples, a portion surrounded by a broken line is added to a stereo receiver. FIG. 4 shows a configuration example corresponding to the example A in the table shown above.

In other words, in the FM stereo receiver, the broadcast signal received by the tuner section 22 through the antenna 21 is transmitted at 10.7 MHz.
After converting it into an intermediate frequency signal of The signal is processed and separated into L and R signals and extracted. Here, in the example A, the maximum frequency deviation is 75 KHz, which is the same as the FM stereo broadcast signal, and only the carrier frequency is lower, at 150 KHz. Therefore, in FIG. 4, for the broadcast signal, the carrier frequency is changed to 150 KHz using the output of the local oscillator 39 in addition to the frequency converter 34 via the recording signal changeover switch 33.
After the signal is converted into a signal, it is supplied to the receiver 7 via the recording amplifier 35 and the recording/reproduction changeover switch 36, and is recorded on the tape 1 as a mass modulation signal. On the other hand, for stereo audio signals other than broadcast signals, such as playback signals from vinyl records, the signals of both the L and R channels are converted into a multi-stereo modulator 31 as shown in FIG. It is converted into a stereo composite signal as shown, and then subjected to frequency modulation using the FM modulator 32 using the same carrier frequency as the intermediate frequency in the FM stereo receiver, and then transmitted via the recording signal changeover switch 33 in the same manner as above. During playback, in either case, the playback signal from the head 7 is switched between the recording and playback selector switch 36.
After being amplified in addition to the regenerative amplifier 37 via the frequency converter 38 and returning to the intermediate frequency using the output of the local oscillator 39, the FM demodulator 24 and the multi-stereo demodulator 25
By sequentially passing through the channels, signals of both the L and R channels can be obtained. On the other hand, Figure 5 shows the points explained in the previous table.
This is an example of a configuration that is compatible with both of (c), in which an FM modulator 41 and an FM demodulator 42 of the carrier wave frequencies shown in the table are provided before the recording amplifier 35 and after the reproducing amplifier 37, respectively. The frequency converters 34, 38 and the local oscillator 39 in the circuit become unnecessary. In this case, the output of the FM demodulator 24 for broadcast signals is input to the FM modulator 41, and the output of the multi-stereo modulator 31 for other stereo audio signals is input to the FM modulator 41. Although the above description deals with the case where the content of the handled audio signal is music, the present invention is not limited to this.

For example, for educational purposes, questions created by an instructor and model answers to the questions are recorded on one or more tracks as one unit of audio signal, and during playback, the part of the question is played back as appropriate, and then the tape is run. It is also conceivable that after the tape has stopped, a suitable track is selected according to the answer of the answerer, and the tape is started to run to reproduce the part of the answer. It is also possible to similarly record various guidance services for business use, especially for customers, as one unit of audio signal and selectively reproduce them as appropriate. Furthermore, in the above embodiment, the audio signal was frequency modulated and recorded, but pulse code modulation (P
A similar effect can be obtained by recording with CM). It is desirable to place more emphasis on sound quality and increase the tape running speed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of a mechanical part of an embodiment of the present invention, FIG. 2 is a diagram showing a recording track pattern on a tape in the same embodiment, and FIG.・Spectrum diagram of composite signal,
FIGS. 4 and 5 are diagrams showing the configuration of an electronic circuit used when the present invention is applied to a recording/reproducing apparatus for stereo audio signals. 1... Endless magnetic tape, 2...
Fixed reel, 7...Magnetic head, 8...
Head moving mechanism, 9...capstan, 10...
...Zentirola, 31...Multi-stereo modulator, 32,41...FM modulator, 24,42...
...FM demodulator, 25...Multi-stereo demodulator.

Claims (1)

[Scope of Claims] 1. An endless tape running mechanism that runs an endless magnetic tape at a speed of 0.7 to 3 m/sec, and a head moving mechanism that moves a magnetic head in contact with the tape stepwise in the tape width direction. , comprising means for modulating and recording an audio signal on the tape via the head as one or a plurality of tracks per unit, and means for reproducing and demodulating the modulated audio signal recorded by this means via the head. A magnetic recording and reproducing device for audio signals, characterized in that: 2. An endless tape running mechanism that runs an endless magnetic tape at a speed of 0.7 to 3 m/sec, a head moving mechanism that moves a magnetic head in contact with the tape stepwise in the tape width direction, and a head moving mechanism that moves the magnetic head in contact with the tape in a stepwise direction, and means for multiple modulating and recording a stereo audio signal as one or more tracks per unit through the head, and means for reproducing and demodulating the stereo audio signal recorded by this means through the head. An audio signal recording and reproducing device characterized by: