JPH09238300A - Magnetic recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record digital data of large scale and various kinds of information by converting digital data into an information signal constituted of a signal area, synthesizing the information signal and a sound signal and recording a synthesized signal in a recording medium. SOLUTION: At the time of recording digital data, a modulator 20 converts digital data into the information signal constituted of the signal area of a prescribed frequency. The information signal is synthesized with the sound signal by a mixing circuit 22 and is converted into the synthesized signal. A recording amplifier 13 records the synthesized signal in the recording medium. At the time of reproduction, a high fidelity head 7 reads the synthesized signal from the recording medium and the synthesized signal which is read is separated into the sound signal and the information signal. The separated information signal is demodulated and digital data is reproduced. Much information data is written and recorded in a magnetic tape without interfering the sound signal and the video signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus such as a home video tape recorder, and more particularly to a magnetic recording / reproducing apparatus for recording / reproducing information such as a program title and recording date / time together with an audio / video signal. .

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS. FIG. 5 is a block diagram of a video signal recording system circuit of a magnetic recording / reproducing apparatus such as a conventional home video tape recorder (hereinafter referred to as “VTR”), and FIG. 6 is a block diagram of the VTR high-fidelity audio signal recording system circuit. It is a block diagram. Further, FIG. 7 is a diagram showing a head arrangement on a rotary drum of a VHS system VTR, and FIG. 8 is a VHS system VTR.
It is a recording pattern diagram on the tape of. Furthermore, FIG. 9 shows V
The frequency distribution of the recording signal of the HS system VTR is shown, (a) of the figure shows the spectrum of the video signal, and (b) of the figure shows the spectrum of the audio signal.

The operation of the conventional device will be described below. First, the video signal shown in FIG. 5 is separated into a luminance signal and a chrominance signal by the Y / C separation circuit 12. In the case of the VHS method, the separated luminance signal is FM-modulated by the luminance signal processing circuit 13, and as shown in FIG. 9A, the luminance FM with the sync signal tip of 3.4 MHz and the deviation of 1 MHz.
While being converted into a signal, the separated color signal is low-pass converted by the color signal processing circuit 15 and converted into a low-pass converted color signal of 629 KHz.

The luminance FM signal and the low-frequency converted color signal are band-limited by a high-pass filter (hereinafter referred to as "HPF") 14 and a low-pass filter (hereinafter referred to as "LPF") 16 so that their frequency bands do not overlap. After being mixed by the mix circuit 17, it is amplified by the recording amplifier 18 and recorded on the video signal track on the magnetic tape shown in FIG.

On the other hand, the Lch audio signal and the Rch audio signal of the stereo audio signal are combined by the mixing circuit 8 shown in FIG. 6 and converted into monaural audio, and then the linear audio signal processing circuit 9 uses a normal audio recording tape. The same processing as that of the recorder is performed, further amplified by the recording amplifier 10, and recorded on the linear audio track on the magnetic tape shown in FIG. 8 via the linear audio head 11.

Here, the Lch audio signal is subjected to FM modulation processing with a 1.3 MHz carrier in the FM audio signal modulation processing circuit 1 and band-limited by a bandpass filter (hereinafter referred to as "BPF") 2 to be required. Only audio signals are selected. Further, the Rch audio signal is FM-modulated by the FM audio signal modulation processing circuit 3 using a 1.7 MHz carrier, and B
Only the necessary audio signal is selected by band limiting with PF4.

The band-limited audio signals of both channels are combined by the mix circuit 5, amplified by the recording amplifier 6, and recorded by the hi-fi head 7 on the hi-fi audio track of the magnetic tape shown in FIG. In addition,
The maximum deviation of this audio signal is ± 150 KHz, and the actual band is about ± 200 KHz. Therefore, the audio signals of the L channel and the R channel can be sufficiently band-limited by the BPFs of 1.3 MHz and 1.7 MHz, respectively.

FIG. 7 shows an example of the arrangement of heads on a rotary drum of a VHS type VTR. In the figure, reference characters L2 and R
A pair of heads indicated by 2 represents a standard mode recording / reproducing video head, and a pair of heads indicated by reference signs L1 and R1 represent a long mode video head. The video head 19 is configured by the mode video head.

Further, the pair of heads indicated by the symbols AL and AR constitute a hi-fi head 7 for both standard and long-time use. These hi-fi head 7 and video head 1
9 is provided on the rotary drum with a predetermined height difference, so that, as shown in FIG. 8, after the hi-fi head 7 deep-records an audio signal on a hi-fi audio track, the video head 19 makes an image. The signal is to be surface-recorded on the hi-fi audio track.

The video head 19 is ± 6 degrees, and
Since the hi-fi head 7 has an azimuth angle of ± 30 degrees, an azimuth difference of at least 24 degrees occurs between the video head 19 and the HiFi head 7, and a difference in azimuth loss occurs. Therefore, as shown in FIG. 8, even if the hi-fi audio track and the video signal track overlap each other,
The video signal and the hi-fi audio signal can be reproduced separately.

FIG. 9 shows the frequency distribution of a VHS recording signal. The figure (a) is a spectrum of a video signal, and the figure (b) is a spectrum of an audio signal. In FIG. 7B, the spectrum of the data signal according to the present invention is also shown by a broken line. As understood from FIG. 9, since the frequency band of the audio signal (audio FM signal) is selected as the frequency band between the video signal (luminance FM signal) and the color signal (low-frequency conversion color signal), In separating audio and video signals,
In addition to separation by the difference in azimuth loss, separation by frequency is also possible.

[0012]

By the way, the above-mentioned conventional apparatus has a function of recording the information of the recorded TV program, for example, the recording date and time, the program title, the setting condition of the timer, and the like, and manages the tape. There are things that can be done easily. In such a conventional VTR,
Identification means (for example, magnetic tape, bar code, etc.) in which a tape identification code for identifying each tape is recorded
Is provided in the tape cassette, and this identification means is read by the reading mechanism provided in the VTR. When the user inputs the program information into the VTR device, the VTR device associates the input information with the tape identification code and the program information to make the VTR device.
It is stored in the internal storage device. In this way, the tape cassette used for recording and the program information are stored in the device in association with each other, so that the information on the program recorded in the tape cassette can be output to the display device as needed. It was possible to manage the tape.

However, since the semiconductor memory is used as the storage device in the VTR device for storing the information about the tape, the total number of identifiable tape cassettes is limited due to the limitation of the storage data capacity of the semiconductor memory. There was a problem. Further, if the amount of information that can be input for one tape cassette is increased and the method of using the information is diversified to increase convenience, there is a problem that the number of tape cassettes recorded in the storage device is reduced.

Further, since the program information is stored in the VTR device side, in order to use the information on the tape cassette, the VTR device to which the program information is input must be reproduced, and the same model is used. Even if there is a different VTR device, there is also a problem that the information about the tape cassette cannot be used.

On the other hand, as an apparatus for recording digital data such as program information on a home VTR, there is one disclosed in Japanese Patent Publication No. 62-53991.
This apparatus records binary information by using a vertical blanking period of a television signal, such as a facsimile which carries out binary pattern transmission. However, there is a problem that a sufficient transmission bit rate cannot be obtained because recording is limited within the vertical blanking period.

For example, the transmission bit rate of British Teletext exemplified in the publication is 6.9375 Mbit /
sec. However, the period during which data can be actually transmitted is one horizontal scanning period of the 17th H in one field,
Moreover, since it does not disturb the synchronization, the synchronization signal part cannot be used,
After all, the data that can be transmitted in one field is 360 bi
t, that is, as low as 18 Kbit / sec in 1 second. In addition, an attempt to increase the recording amount by using a plurality of horizontal scanning periods within the vertical blanking period also causes interference on the television screen, and the number of lines is naturally limited.

The present invention has been made in view of the above problems, and provides a magnetic recording / reproducing apparatus such as a home VTR capable of recording digital data of large-scale and various kinds of information. Is an issue.

[0018]

Means for Solving the Problems The present invention has the following arrangement to achieve the above object. That is, the magnetic recording / reproducing apparatus according to the present invention is a magnetic recording / reproducing apparatus for recording / reproducing an audio signal and a video signal, wherein each bit of digital data is associated with a signal area of a predetermined frequency. Conversion means for converting the digital data into an information signal composed of the signal area, synthesizing means for synthesizing the information signal and the audio signal to generate a synthetic signal, and recording means for recording the synthetic signal on a recording medium. Reproducing means for reproducing the combined signal recorded on the recording medium, separating means for separating an audio signal and an information signal from the reproduced combined signal, and the digital data from the separated information signal. And demodulation means for demodulating.

According to a second aspect of the present invention, there is provided a magnetic recording / reproducing apparatus in which the converting means of the magnetic recording / reproducing apparatus according to the first aspect comprises an oscillator for generating an oscillation signal of a predetermined frequency, The oscillation signal is output in association with one of the values "1" or "0" of each bit of data, and is associated with the other value of the value "1" or "0" of each bit. It is configured to stop the output of the oscillation signal and convert the digital data into an information signal.

Further, in the magnetic recording / reproducing apparatus according to the third aspect of the present invention, the conversion means of the magnetic recording / reproducing apparatus according to the first aspect of the present invention respectively outputs the first and second oscillation signals of predetermined frequencies. An oscillator for generating is provided, which outputs one of the first or second oscillation signals in association with one of the values "1" or "0" of each bit of the digital data, and outputs "1" of each bit. Or the value of "0" in correspondence with the other value, and outputs the other of the first or second oscillation signal to convert the digital data into an information signal.

Furthermore, in the magnetic recording / reproducing apparatus according to the invention of claim 4, the frequency of the oscillation signal of the oscillator provided in the converting means of the magnetic recording / reproducing apparatus of claim 2 is the audio signal. Set below the carrier frequency, the conversion means is configured to convert the digital data into an information signal.

Furthermore, a magnetic recording / reproducing apparatus according to a fifth aspect of the present invention is configured such that the magnetic recording / reproducing apparatus according to the first aspect comprises a storage means for accumulating and holding the reproduced combined signal. ing.

The magnetic recording / reproducing apparatus of the present invention having the above structure operates as follows. That is, according to the magnetic recording / reproducing apparatus of the first aspect of the present invention, when recording digital data, the converting means converts the digital data into an information signal having a signal area of a predetermined frequency. In this conversion, the conversion means associates the value of each bit of the digital data with the frequency and generates an information signal having a signal region of this frequency. This information signal is combined with the audio signal by the synthesizing means and converted into a synthetic signal, and the recording means records the synthetic signal on the recording medium. When reproducing, the reproducing means reads the composite signal from the recording medium, and the separating means separates the read composite signal into an audio signal and an information signal. Then, the demodulation means demodulates the separated information signal to reproduce digital data.

According to the magnetic recording / reproducing apparatus of the second aspect of the invention, the transmitter provided in the converting means of the magnetic recording / reproducing apparatus of the first aspect of the invention transmits the transmission signal according to the value of the bit of the digital data. Output is controlled. That is, when the value of the bit is 1 or 0, the outgoing signal is output,
At the other time, the output of the outgoing signal is stopped. Thereby, one of the bits of the digital data is associated with the signal region of the predetermined frequency, and the binary value is identified.

Further, according to the magnetic recording / reproducing apparatus of the third aspect of the invention, the oscillator provided in the converting means of the magnetic recording / reproducing apparatus of the first aspect of the invention transmits the transmission signal according to the bit value of the digital data. Output is controlled. That is, when the bit value is 1 or 0, the oscillation signal of the first frequency is output, and when the bit value is the other, the oscillation signal of the second frequency is output. As a result, one and the other of the bits of the digital data are associated with signal regions of different predetermined frequencies, and binary values are identified.

Further, according to the magnetic recording / reproducing apparatus of the invention described in claim 4, the frequency of the oscillation signal of the oscillator provided in the converting means of the magnetic recording / reproducing apparatus of claim 2 is the voice signal. When the frequency is set to be equal to or lower than the carrier frequency of, the frequency band of the information signal is set below the audio signal frequency band. This allows frequency separation when separating the audio signal and the information signal.

Furthermore, according to the magnetic recording / reproducing apparatus of the fifth aspect of the invention, the storage means included in the magnetic recording / reproducing apparatus of the first aspect accumulates and holds the reproduced combined signal. By reading the composite signal stored and held in advance from the storage means, a large amount of data can be displayed instantaneously without being restricted by the reproduction speed from the magnetic tape.

Therefore, according to the magnetic recording / reproducing apparatus of the present invention having the above structure, a large amount of information data can be written and recorded on the magnetic tape without interfering with the audio signal and the video signal.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION A magnetic recording / reproducing apparatus according to an embodiment of the present invention is a digital data "1" or "0".
Is converted into an information signal in association with the presence or absence of a signal area of a predetermined frequency component, and this information signal is recorded on a high-fidelity audio track on a magnetic tape together with the audio signal.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4. Here, FIG. 1 is a block diagram of an audio signal recording system circuit of a magnetic recording / reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is an audio signal reproducing system circuit of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. It is a block diagram. 3 is a block diagram of a modulation circuit that constitutes the audio signal recording system circuit shown in FIG. 1, and FIG. 4 is a block diagram of another modulation circuit.

First, the recording operation of the magnetic recording / reproducing apparatus according to this embodiment will be described with reference to FIG. The configuration of the present embodiment is obtained by adding a digital signal modulator 33 to the configuration of the conventional device shown in FIG. 6 and converting the conventional digital data by the mix circuit 22, as will be described later. They are different in synthesizing a signal and an audio signal, and other video signal system circuits and linear audio circuits are the same as those of the conventional device, and the description of their configurations and operations will be omitted.

Digital data such as program information is FM-modulated by a modulator 20 of the digital signal modulator 33 with a carrier of 1 MHz and converted into an information signal. Here, when the data transfer rate is 10 Kbit / sec and the deviation (frequency displacement width) is 10 KHz, the frequency band of the information signal is about 1 MHz ± 15 KHz.
The PF 21 removes unnecessary signal components only through this frequency band. After the unnecessary signal component is removed from the information signal by the BPF 21, the information signal is combined with the audio signal by the mix circuit 22 to be converted into a composite signal, which is further amplified by the recording amplifier 6 and passed through the hi-fi head 7 through the hi-fi head 7.
It is recorded on the hi-fi audio track on the magnetic tape shown in.

Next, the operation during reproduction will be described with reference to FIG. The configuration of the reproducing system shown in the figure is different from that of the recording system described above in that the digital signal processing unit 34 is added to the conventional configuration. In FIG. 2, 1.
The BPF 2 that passes the frequency band of 3 MHz separates only the necessary frequency band from the signal reproduced by the hi-fi head 7, and the FM audio signal demodulation processing circuit 24 makes the BPF 2
The signal component passing through 2 is demodulated and an Lch audio signal is output. Similarly, the Rch audio signal is obtained by demodulating the signal component separated by the BPF 4 that passes the frequency band of 1.7 MHz by the FM audio signal demodulation processing circuit 25.

On the other hand, the synthesized signal (the signal obtained by synthesizing the information signal and the voice signal) reproduced by the high-fidelity head 7 from the high-fidelity voice track is transmitted by the BPF 21 constituting the input stage of the digital signal processing unit 34 added according to the present invention. After being separated and reproduced as an information signal, it is demodulated into digital data by the demodulation processing circuit 26, further stored in a digital memory 27 composed of a semiconductor memory, and then output. By once accumulating in the digital memory 27 and reading the digital data from the digital memory 27, it is possible to instantly display even a large amount of data such as text information in text broadcasting on the television screen. Therefore, processing with a short waiting time becomes possible.

Here, the digital data stored in the digital memory 27 can be used as character information displayed on the television screen as described above, or can be used for setting a timer or the like. In addition, BPF2 and B
Each of the PFs 4 can be used for both the recording side and the reproducing side, but they may be provided separately for the recording side and the reproducing side with an emphasis on reproduction quality.

As shown in FIG. 9B, the band of the Lch audio signal is 1.3 MHz ± 200 KHz, and the band of the information signal obtained by converting the digital data is 1 MHz ± 15 K.
Since the frequencies are Hz, the bands do not overlap with each other, which enables frequency separation with a predetermined filter. Further, the center (1 MHz) of the frequency band of the information signal is located at the upper end of the band of the low frequency conversion color signal of the video signal shown in FIG. 9A, and the low frequency conversion color signal and the information signal are Although frequency overlap occurs, in this case, as described in the conventional example, it is possible to separate and reproduce by utilizing the difference in azimuth loss between the heads.

Next, the modulator 20 constituting the digital signal modulator 33 will be described below. The modulator 2 in FIG.
The structure of 0 is shown. The oscillator 28 shown in the figure continuously oscillates at a predetermined frequency, and supplies the oscillation signal to the switch 29. The switch 29 is ON / OFF controlled according to the value of each bit of the digital data, and converts the digital data into an information signal including the presence or absence of a transmission signal area. At the time of reproduction, the presence or absence of a transmission signal area is detected from the information signal and demodulated to the original digital data. The information signal may be generated by directly controlling the oscillation operation of the oscillator with digital data.

FIG. 4 shows another configuration example of the modulator 20. The oscillators 30 and 31 continuously oscillate at different predetermined frequencies, for example, 0.99 MHz and 1.01 MHz, and their outputs are input to the switch 32. The switch 32 performs a switching operation in accordance with the value of each bit of the digital data, and one of "1" and "0" of the digital data is a transmission signal of 0.99 MHz, and
The other is associated with a 1.01 MHz outgoing signal.

At the time of reproduction, a detector for detecting each frequency component identifies each transmission signal area and demodulates the information signal into digital data. The modulator shown in FIG. 4 has a more complicated structure than the modulator shown in FIG. 3, but since each of the binary values of each bit of digital data is expressed by a specific frequency signal, the modulator shown in FIG. It is possible to effectively prevent the occurrence of a read error due to data loss (dropout) due to scratches on the.

It is also possible to use an oscillator capable of changing the oscillation frequency so as to obtain the same function as that of the modulator shown in FIG. That is, by changing the oscillation frequency of the oscillator according to the value of the digital data, it is possible to realize the same function as that of the modulator shown in FIG. Further, when the oscillator or the switch is switched according to the value of the bit of the digital data, the oscillating wave becomes discontinuous and the frequency band widens, but since the unnecessary component is removed by the BPF 21 in FIG. 1, it interferes with other signals. There is no such thing.

In the above description of this embodiment, frequency modulation was used as the modulation method for converting digital data into information signals, but this may be amplitude modulation. By converting digital data into an information signal in a narrow frequency band, it is possible to record and reproduce without interfering with other recording signals (audio signal, video signal).
This is because the amplitude modulation can obtain almost the same effect as the frequency modulation.

For example, when amplitude modulation is used to convert digital data into an information signal, the carrier frequency is 1 MHz and the data transfer rate is 10 Kbit.
/ Sec, the recorded signal frequency is 1MHz ±
It becomes 5 KHz. Therefore, even if the information signal is generated by using amplitude modulation, it can be easily separated from other signals by the narrow band filter, the interference with other signals is extremely small, and the reproduced voice of the same quality as the conventional one and You can get the playback video.

On the other hand, when frequency modulation is used as the modulation method, if the carrier frequency is 1 MHz, the data transfer rate is 10 Kbit / sec, and the deviation is 10 KHz, the recorded signal frequency is 1 M.
It becomes about ± 15 KHz, and the frequency band becomes wider than that of the amplitude modulation, but it is within the range where it can be easily separated from other signals by the filter, and the interference with other signals is extremely small. Also, in this case, compared to amplitude modulation,
The S / N ratio can be improved.

Further, in this embodiment, the frequency band (1.0 M) between the low frequency band color signal frequency band (629 KHz) and the Lch side frequency band (1.3 MHz) of the audio signal is used.
Although the interference given to other signals is reduced by setting (Hz) as the information signal frequency band, the information signal frequency band is not particularly limited to this frequency band, and this is not a limitation of the present invention. This is not the one that constrains the essence.

In describing the embodiment, the data transfer rate is set to 10 Kbit / sec for convenience.
However, according to the present embodiment example, 100 Kbit / s
It is possible to transfer data up to about ec, and data can be transferred at high speed. If the recording data transfer rate is 10 Kbit / sec as in the present embodiment, the NTSC
In the method, 1 field is approximately 16 msec, so 1
160 bits of digital data can be recorded per field. As the information to be recorded, if the date of recording, the receiving channel, and the program title of the data of the conventional tape management system, the amount of data to be recorded is several hundred bits.
It is about a degree, and it is possible to record in 0.1 seconds or less. Even when a teletext program is recorded, if the data amount is about 10 Kbit, it can be recorded in about 1 second.

The data transfer rate is 10 Kbit / s.
By modulating the data of ec at 1.0 MHz, the frequency band of the information signal is set to a frequency band having high recording / reproducing sensitivity of the hi-fi head. Therefore, in the case of this embodiment, the hi-fi head can record and reproduce the information signal with a practical signal strength.

Further, according to the present embodiment, when the contents of the information to be recorded are timer setting information such as recording date and time, reception channel, etc., these information are V
Since it is already stored as digital data in the timer of TR, in this case, it is also possible to record such digital data without inputting from the outside.

[0048]

As described above, according to the present invention,
The following effects can be obtained. That is, according to the invention described in claim 1, since 1 or 0 of digital data is converted into an information signal in association with a signal region of a predetermined frequency component and recorded together with an audio signal, the recording data capacity on the device side is reduced. There is no restriction, the recording amount of information can be significantly increased, and various kinds of information can be recorded simultaneously.

According to the second aspect of the invention, one of the digital data 1 or 0 is converted into an information signal in association with the signal area of a predetermined frequency component and recorded together with the audio signal. It is possible to simply configure a conversion unit that converts the signal into an information signal.

According to the third aspect of the present invention, the values of both "1" and "0" of the digital data are converted into information signals by associating them with the signal areas of different predetermined frequency components. Since the data is recorded together with the signal, the information can be correctly reproduced even if the signal is partially lost due to a scratch on the magnetic tape or the like.

Furthermore, according to the invention of claim 4, since the digital data is converted into an information signal having a frequency component equal to or lower than the carrier frequency of the audio signal and recorded in the audio signal track together with the audio signal, the audio signal is recorded. Information can be recorded on the magnetic tape without concern about interference with other signals such as video signals and video signals.

Further, according to the invention of claim 5, since the reproduced digital data is accumulated and held in the storage means, even if it is a large amount of data such as character information of teletext, By reading the information from the storage device, the information can be promptly displayed on the screen.

[Brief description of drawings]

FIG. 1 is a block diagram of an audio signal recording system circuit of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of an audio signal reproduction system circuit of the magnetic recording / reproducing apparatus according to the embodiment of the present invention.

FIG. 3 is a block diagram of a modulation circuit of the magnetic recording / reproducing apparatus according to the embodiment of the present invention.

FIG. 4 is a block diagram of another modulation circuit of the magnetic recording / reproducing apparatus according to the embodiment of the present invention.

FIG. 5 is a block diagram of a video signal recording system circuit of a conventional magnetic recording / reproducing apparatus.

FIG. 6 is a block diagram of an audio signal recording system circuit of a conventional magnetic recording / reproducing apparatus.

FIG. 7 is a diagram showing a head arrangement on a rotating drum of a conventional magnetic recording / reproducing apparatus.

FIG. 8 is a diagram showing a recording pattern on a magnetic tape by a conventional magnetic recording / reproducing apparatus.

FIG. 9A is a diagram showing a frequency spectrum of a video signal of the VHS type magnetic recording / reproducing apparatus. (B)
It is a figure showing the frequency spectrum of the audio | voice signal of the magnetic recording / reproducing apparatus of a VHS system.

[Explanation of symbols]

 1,3 FM audio signal modulation processing circuit 2 band pass filter (for 1.3 MHz band) 4 band pass filter (for 1.7 MHz band) 5,8,17,22 mix circuit 6,10,18 recording amplifier 7 hi-fi head 9 Linear audio signal processing circuit 11 Linear audio head 12 Y / C separation circuit 13 Luminance signal processing circuit 14 HPF 15 Color signal processing circuit 16 Low pass filter 19 Video head 20 Modulator 21 Band pass filter (for 1.0 MHz band) 23 Playback Amplifier 24,25 FM voice signal demodulation processing circuit 26 Demodulation processing circuit 27 Digital memory 28,30,31 Oscillator 29,32 Switch 33 Digital signal modulator 34 Digital signal demodulator

Claims (5)

[Claims] 1. A magnetic recording / reproducing apparatus for recording / reproducing an audio signal and a video signal, wherein each bit of digital data is associated with a signal area of a predetermined frequency, and the digital data is an information signal comprising the signal area. Converting means for converting the information signal and the audio signal to generate a combined signal; a recording means for recording the combined signal in a recording medium; and the combining recorded in the recording medium. A reproducing unit for reproducing a signal; a separating unit for separating an audio signal and an information signal from the reproduced combined signal; and a demodulating unit for demodulating the digital data from the separated information signal. A magnetic recording / reproducing apparatus characterized in that 2. The conversion means comprises an oscillator for generating an oscillation signal of a predetermined frequency, and 1 for each bit of digital data.
Alternatively, the oscillation signal is output in association with one of the values of 0, and the output of the oscillation signal is stopped in association with the other of the values of 1 or 0 of each bit to output the digital data. The magnetic recording / reproducing apparatus according to claim 1, wherein the magnetic recording / reproducing apparatus converts the information signal. 3. The conversion means comprises oscillators for generating first and second oscillation signals each having a predetermined frequency, and the conversion means is associated with one of the values 1 or 0 of each bit of digital data. One of the first or second oscillation signal is output, and the other of the first or second oscillation signals is output in association with the other value of 1 or 0 of each bit to output the digital data. The magnetic recording / reproducing apparatus according to claim 1, wherein the magnetic recording / reproducing apparatus converts the information signal. 4. The frequency of the oscillation signal of the oscillator is set to be equal to or lower than the carrier frequency of the audio signal, and the conversion means converts the digital data into an information signal. Magnetic recording / reproducing device. 5. The magnetic recording / reproducing apparatus according to claim 1, further comprising storage means for accumulating and holding the reproduced combined signal.