JPS6139287A - Recording regenerating device of plural narrow band signal - Google Patents

Abstract

PURPOSE:To enable the titled device to record and regenerate plural signals with a wide frequency band for a long time sufficiently raising recording density without deterioration of a quality such as a wow flutter by recording and regenerating a narrow band signal of a multi-channel with a rotary head with very fast relative speed between recording media and a head. CONSTITUTION:A rotary heads 131 and 132 for recording are respectively fitted to a rotary cylinder 54 facing 180 deg. and rotary heads 141 and 142 for regeneration are respectively fitted to a position of an angle theta which goes after the rotation direction. Further, the rotary heads 141 and 142 for regeneration are fitted at the position lower by height (h) only comparing with the rotary heads 131 and 132 for recording. A regenerating signal is respectively supplied to a (n) number of band filters 181-18n, a FM voice signal of the (i) channel is separated, filtered and removed from No.i band filter 18i and is supplied to an envelope detecting circuit 32. An alarm signal generator 33 respectively detecs the level of an input envelope detecting signal of a (n) channel and generates an alarm signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a recording and reproducing device for a plurality of narrowband signals, and in particular for signals such as audio signals that are narrowband compared to standard video signals, The present invention relates to a recording/reproducing apparatus for recording and reproducing signals on a recording medium using a rotary head.

BACKGROUND ART In recent years, information communication systems such as advanced information communication systems (INS) have become increasingly complex and voluminous. This trend is particularly noticeable with voice information, and among them, information using telephone lines is becoming increasingly diverse. This voice information communication system using telephone lines requires a device that can accurately and efficiently record the voice information that arrives irregularly 24 hours a day, and reproduce it as needed. Conventionally, as a device compatible with this, a recording/playback device is known that can record audio signals of multiple channels for a long time and playback the recorded audio signals.

This recording/reproducing device records multiple channels of audio signals on a magnetic tape by simultaneously forming multiple tracks using a fixed head with a multi-head gap.
Because the tape running speed was extremely slow due to the need for long-term recording, the relative speed between the tape and head was not sufficient, and the problem was that only low-quality audio signals with a narrow signal transmission band could be recorded and played back. Kaatsu. Further, since the above-mentioned conventional recording/reproducing apparatus records audio signals of many channels on multi-tracks using a fixed head, there are problems in that the recording density is low and the apparatus becomes large.

Furthermore, audio signal recording and reproducing devices used for the above purposes may use the audio information later as evidence, and recording errors cannot be tolerated, so some kind of monitoring means is required to ensure that recording is always being performed reliably. Met.

Therefore, the present invention simultaneously records narrowband signals such as audio signals for multiple channels using a rotating head, and at the same time, when recording, a separately installed playback head plays back the green signal recorded on the recording track for monitoring. By doing so, it is an object of the present invention to provide a recording and reproducing apparatus for a plurality of narrowband signals that solves the above-mentioned problems and also satisfies the above-mentioned requirements.

Means for Solving the Problems The present invention provides a modulation means, a mixing circuit, a recording rotary head, a reproducing rotary head, and a frequency separation and demodulation means.

It also serves as a warning means. The modulation means modulates a plurality of channels of signals, each of which has a narrower band than the standard video signal, into a plurality of modulated wave signals of different bands and outputs the modulated signals.

The mixing circuit mixes these multiple modulated wave signals.

A frequency division multiplexed signal is obtained by The recording rotary head and the reproducing rotary head are each mounted on substantially the same rotating body, and their mounting positions are such that the recording rotary head unifies the output multiplexed signal of the mixing circuit onto the recording medium. The reproducing rotary head is set at such a position that when the recording track of the book is formed and recorded, the reproducing rotary head scans the recording track behind the recording rotary head.

Further, the frequency separation and demodulation means extracts the recorded multiplexed signal from the recording track reproduced by the reproducing rotary head during the signal recording period by the recording rotary head.
After extracting the plurality of modulated wave signals separately and in parallel by frequency separation, the reproduced modulated wave signal of the desired channel is demodulated to obtain the reproduced narrowband signal of the desired channel A7.

Further, the alarm means detects the reproduction level of each of the plurality of modulated wave signals in the recorded multiplexed signal of the recording track reproduced by the reproduction rotary head, and detects the reproduction level of each of the plurality of modulated wave signals. Generates an alarm when the modulated wave signal is lost.

Narrowband signals from multiple channels are simultaneously recorded on a single recording track by a rotating recording head, but the relative speed between the rotating recording head and the recording medium is extremely large compared to when a fixed head is used. .

In addition, the state of signal recording by the recording head can be constantly monitored by the alarm means, the frequency component i, and the demodulation means, so that any one of the modulated wave signals of multiple channels can be monitored.
Even if the modulated wave signal of a channel is lost, an alarm is immediately issued. Hereinafter, the present invention will be described in more detail along with examples.

Embodiment FIG. 1 shows a block system diagram of an embodiment of the apparatus of the present invention. In the figure, n-channel audio signals are input to n input terminals 11 to 1n (where n is an integer of 2 or more).

This n channel A7 audio signal is supplied to automatic level adjustment circuits (A10 circuits) 31 to 3n after unnecessary high frequency components are removed by corresponding low pass filters 21 to 2n.
Here, fluctuations in the average level are detected and the levels are adjusted so that they are recorded at an appropriate and sufficient level. ALC
The audio signals taken out from the circuits 31 to 3n are processed by noise reduction circuits 41 to 4n to suppress noise in the transmission system and improve the dynamic range of the signal, converting high frequency components into low frequency components to improve the S/N ratio. The signals are supplied to FM modulators 61-6n through pre-emphasis circuits 51-5n, respectively, which amplify the level.

The FM modulators 61 to 6n perform frequency modulation (FM) L on carrier waves selected at mutually different frequencies using input audio signals, thereby frequency modulating audio signals (FM) in mutually different bands.
M audio signal) is output.

Here, the band of the output FM audio signal of the FM modulator 61 is selected to be the lowest, and the band of the output FM audio signal of the FM modulator 6n is selected to be the highest. Each FM audio signal taken out from the FM modulators 61-6n is supplied to a corresponding low-pass filter (which may be a bandpass filter) 71-7n, where unnecessary high frequency components are removed. Low pass filter 7+, 72
,...711 are shown in Fig. 2 (B) and (C
), as shown in (D), the upper limit cutoff frequency is fllll+
, fL, and fwn. The upper limit cutoff frequency fwn of the low-pass filter 7n is approximately equal to the upper limit frequency of the transmittable bandwidth BWIIax shown in FIG. 2(A) 1 of this recording/reproducing apparatus. In this way, n channels of FM in different bands are transmitted from the low-pass filters 71 to 7n.
Audio signals are respectively extracted. FM modulators 61 to 6n and low-pass filters 71 to 7n constitute modulation means 8, which supplies the n-channel FM audio signal to mixing circuit 9.

The mixing circuit 9 generates a frequency division multiplexed signal of n''/-i7 channel FM audio signals by mixing the nji1 channel FM audio signals.This frequency division multiplexed signal is shown in FIG. A signal with a frequency spectrum like
Recording amplifier 10. Switch 11 connected to contact R
and a recording rotary head 1 via a rotary transformer 12.
31 and 132, respectively. In addition, in Figure 3, 4
2+ indicates the frequency spectrum of the first channel FM audio signal extracted from the low-pass filter 71, and 422
．． 42n indicates the frequency spectrum of the FM audio signal of the second channel and the n-th channel extracted from the low-pass filter 72.7n, respectively.

Next, a description will be given of the mounting structure of the recording rotary heads 131 and 132 and the reproducing port 1 heads 141 and 142 to the rotary cylinder, and the tape running system of this recording and reproducing apparatus. FIG. 4 is a dimensional plan view of a tape running system of an example of the apparatus of the present invention, and this tape running system is similar to an existing helical scan type VTR and is well known except for the head arrangement. In FIG. 4, when the cassette 45 is loaded, the magnetic tape 48 between the supply reel 46 and the take-up reel 47 within the cassette 45 is moved to the loading posts 49, 50, .
The loading posts 49 to 52 are pulled out of the cassette 45 by the cassettes 51 and 52 and come to rest at the positions shown in FIG.
It comes into contact with the rotating cylinder 54 and the control head 55, respectively. Next, the pinch roller 56 moves and presses the capstan 57 with the magnetic tape 58 interposed therebetween. As a result, the magnetic chip 148 begins to travel toward the take-up reel 47 side. Further, the rotating cylinder 54 is rotated counterclockwise by a head motor (not shown).

Recording rotary heads 13+ and 132 are respectively attached to the rotary cylinder 5/I so as to face each other by 180', and reproducing rotary heads 13+ and 132 are mounted at an angle θ in the direction of rotation relative to the recording rotary heads 131 and 132. Rotating heads 141 and 14
2 are attached respectively. Further, as shown in FIG. 5, which is a developed view of the rotary cylinder 54, the recording rotary head 1
31 and 132 are respectively mounted at the same height position, and the reproduction rotary heads 141 and 142 are also respectively mounted at the same height position. Furthermore, a rotating head 141 for reproduction
and '142 are mounted at a height h lower than the recording rotary heads 131 and 132. This height 11 is such that when the recording rotary heads 131 and 132 form one recording track on the magnetic tape 48, the recording rotary heads 14+ and 142
The distance is selected so that the recording rotary heads 13+ and 132 can perform follow-up scanning. As is well known, the recording rotary heads 131 and 132 alternately form recording tracks that are inclined with respect to the longitudinal direction of the magnetic tape 48. , the frequency division multiplexed signal described above is recorded.

Referring again to FIG. 1, as described above, the reproducing rotary heads 14+ and 142 scan the recording track on which recording is being formed by the recording rotary heads 131 and 132 with a delay. As a result, the edge frequency division multiplexed signals of records 1 to 1 are reproduced by the reproduction rotary heads 141 and 142, and the rotary transformer 15. The signal is supplied to n bandpass filters 181 to 18n through a switch 16 and a regenerative amplifier 17 connected to the contact R side, respectively. The frequency characteristics of the bandpass filters 18+ and 182.18n are
They are selected as shown in Figures (E), ('F), and (G). As a result, the FM audio signal of the i-th channel is separated and filtered from the i-th band filter 18i among the n band-pass filters 181 to 18n. The n-channel reproduced FM audio signals taken out separately from the bandpass filters 181 to 18n are sent to the corresponding preamplifier 19.
Terminals 20+ to 20 of the switch circuit 20 via 1 to 19n
While the signal is supplied to the mouth, it is also supplied to the envelope detection circuit 32.

The switching circuit 20 is controlled by a control signal from an input terminal 23 to selectively output a reproduced FM audio signal of a desired negative channel.

The reproduced FM audio signal of the desired negative channel selectively outputted from this switch circuit 20 is supplied to a single FM demodulator 22 through a limiter 21.

Here, the FM demodulator 22 is a single circuit that converts the reproduced FM audio signal of any negative channel among the n channels into FM
However, since the reproduced FM audio signals of a total of n channels and A7 channels exist within a fairly wide frequency band, input terminal 2
The internal constants etc. are changed by the control signal input to 3. Thereby, the FM demodulator 22 can perform FM demodulation of a desired - reproduced FM audio signal among the n-channel reproduced FMRr voice signals existing within a wide frequency band.

The reproduced audio signal of the desired negative channel extracted from the FM demodulator 22 is supplied to a switching noise canceller 25 through a low-pass filter 24 for removing the demodulated carrier frequency. On the other hand, the rotating head selection signal is supplied to the cancel pulse generation circuit 27 via the input terminal 26, where it is converted into a cancel pulse and then supplied to the switching noise canceller 25. As a result, the switching noise canceller 25 moves to the reproducing rotary head 141°1.
42 (this switching is done by a switcher (not shown) provided on the output side of the regenerative amplifier 17).
This eliminates switching noise caused by The output reproduction audio signal of the switching noise canceller 25 is sent to a de-emphasis circuit 28. The signal is output from an output terminal 31 through a noise reduction circuit 29 and an amplifier 30, and is monitored.

On the other hand, the envelope detection circuit 32 has an n-channel reproduction F.
The respective envelopes of the M audio signals are detected and the respective envelope detection signals are supplied to the alarm signal generator 33. The alarm signal generator 33 detects the level of each n-channel input envelope detection signal separately, generates an alarm signal when the level falls below a very small predetermined level, and supplies it to the display 34 while passing it through the OR circuit 35. The signal is supplied to the good news sound generator 37.

The display 34 issues an alarm by displaying an abnormal channel whose envelope detection level has fallen below the predetermined level, that is, where the reproduced FM signal is substantially missing.

At the same time, if the reproduced FM code is substantially lost in any one of the n channels, an alarm sound is generated from the speaker 38 by the signal output from the false alarm sound generator 37. . Furthermore, in this example,
Even if an abnormality occurs in the power supply circuit 36 for some reason,
At the same time as the speaker 38 generates an alarm sound, the power supply alarm display 39 performs a display operation and issues a ledger.

Therefore, the blocks 32 to 35 and 37 to 39 described above constitute alarm means. By using this ledger means, when this recording and reproducing device is applied to record N-channel audio signals all day long, it will notify you of abnormalities related to recording and abnormalities in the power supply, even if a human being is not present and constantly monitoring. be able to.

Note that reproduction can also be performed by the recording rotary heads 131' and 132, and in that case, the switches 11 and 16 are generally switched to the contact P side. The frequency division multiplexed signal is subjected to the above-mentioned reproduction signal processing, and on the other hand, the frequency division multiplexed signal reproduced by the reproduction rotary heads 141 and 142 is blocked from being supplied to the subsequent stage circuit by the switch 16.

Although a detailed explanation has been omitted since it is not directly related to the present invention, since the head servo circuit and capstan servo circuit have no synchronization signal in the audio signal, the output of the internal oscillator is Servo operation is performed based on the reference signal.

Furthermore, the present invention is not limited to the above-described embodiments; for example, the plurality of signals to be recorded and reproduced may be signals other than audio signals as long as they have a narrower band than the standard video signal; A plurality of modulated wave signals having different bands may be obtained by modulating using a modulation method other than modulation. In addition, the switch circuit 20 selectively outputs only the reproduced FM audio signal of the desired negative channel and extracts only the demodulated audio signal of one channel, but by installing two or more FM demodulation systems, demodulation Of course, the audio signal can have any desired number of channels, such as two or more channels.

Effects of the Invention As described above, according to the present invention, even if the traveling speed of the recording medium is slowed down, the relative speed between the recording medium and the head is much faster than that of the conventional device using a fixed head. Because it records and reproduces narrowband signals of multiple A7 channels, the frequency band is wide (200H1 to 3400H7 in the conventional fixed head type device, but 2 in the present invention).
0Hz ~ 15kHz) Wow/flutter multiple signals
:! It is possible to sufficiently increase the recording density and record and play back for a long time without deteriorating the quality of the device. Since the recording status of narrowband signals can be automatically monitored at all times, it is suitable for applications where recording errors cannot be tolerated, especially when recording multiple narrowband signals over a long period of time. It has certain characteristics.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the device of the present invention;
FIG. 2 is a diagram that does not show the frequency characteristics of each part in the block system shown in FIG. FIG. 4 is a plan view showing an example of the tape running system etc. of the apparatus of the present invention, and FIG. 5 is a diagram showing the mounting positional relationship of the rotary head. 11-1n...Input terminal, 61-6n...FM modulator, 71-7n...Low-pass filter, 8...Modulation means, 9...Mixing circuit, 13+, L32...Recording Rotating head for use, 141, 14.2... Rotating bed for reproduction,
181. ~1.8n... Bandpass filter, 20... Switch circuit, 22... FM demodulator, 31... Playback audio signal output terminal, 32... Envelope detection circuit, 34... Display, 37...Y alarm generator, 48...Full width erasing head, 54...Rotating cylinder. TWI TW2 msR+Iku-4 Figure 5

Claims (1)

[Claims] a modulation means for converting a plurality of channels of signals, each of which has a narrower band than a standard video signal, into a plurality of modulated wave signals of different bands; A mixing circuit that frequency-division multiplexes multiple modulated wave signals, and a recording device that is attached to a rotating body and that sequentially repeats recording the output multiplexed signal of the mixing circuit by forming a single recording track on a recording medium. A reproducing device including a rotary head and an attachment position of the recording rotary head to the rotating body so that the recording rotary head scans the recording track that is being recorded by the recording rotary head with a delay of the recording rotary head. a rotary head, and frequency separation and demodulation means for obtaining a reproduced narrowband signal of a desired channel from a previously recorded multiplexed signal of the recording track reproduced by the reproducing rotary head during a signal recording period by the recording rotary head; Detecting the reproduction level of each of the plurality of modulated wave signals in the recorded multiplexed signal of the recording track reproduced by the reproducing rotary head during the signal recording period by the recording rotary head, 1. A recording and reproducing device for a plurality of narrowband signals, comprising an alarm means for generating an alarm when one or more modulated signals among the modulated wave signals are missing.