JPS6080173A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To record and reproduce the video and digital signals independently of each other and to improve the recording density of a magnetic tape, by recording the PCM sound signal accompanied with a TV signal to an area between tracks where video signals are recorded. CONSTITUTION:A luminance signal Y and color difference signals R-Y and B-Y are compressed respectively and then combined. These combined signals are supplied to a primary head 8 after FM modulation and addition with a pilot signal and recorded to a track 10 of a tape 1. At the same time, an addition signal is supplied to a switch 30 and the signals containing the signals of a vertical fly- back line period and some periods before and after said fly-back line period are extracted and supplied to a secondary head 7 to be recorded to a track 11. While the sound signal is combined 25 with digital data after A/D conversion 24 and then supplied to a head 9 after modulation to be recorded to a track 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic recording and reproducing apparatus that includes a main rotary magnetic head and a sub-rotary magnetic head and performs recording and reproducing of television signals.

[Background of the invention]

Conventionally, the method for recording digital signals such as PCM audio signals (hereinafter referred to as PCM audio signals) as television signals involves inserting digital signals into the vertical blanking period or horizontal blanking period of the video signal. record or
Regarding a two-head helical force scan type magnetic recording/reproducing device, a so-called overlap recording method, in which recording is performed by extending the entire overlap recording/reproducing period of the heads, has been proposed, and many attempts have been made.However, the former two methods have not been successful. If the insertion period of the digital signal is not sufficient and the amount of information is large, it may not be possible to record it completely, and since it is inserted within the video signal, it is not necessarily the most suitable recording time for the digital signal. However, problems arise in that it is not possible to perform modulation, and that it is troublesome to extract the signal of the digital part during playback.

On the other hand, in the latter case, the recording part of the digital signal is separated in location, so there is no signal modulation problem, but it is necessary to wrap the magnetic tape around the head cylinder extra time for overlap recording. Therefore, the recording density will decrease accordingly. Furthermore, the track width of the digital signal recording portion is necessarily equal to the track width of the video signal recording portion, and this is not necessarily an efficient recording method.

[Purpose of the invention]

An object of the present invention is to eliminate the drawbacks of the above-mentioned prior art and to record video signals and their accompanying (
Another object of the present invention is to provide a magnetic recording and reproducing device capable of recording and reproducing digital signals.

[Summary of the invention]

In order to achieve all of these objectives, the present invention records most of the video signal in a television signal with a main rotating magnetic head,
The remaining part of the video signal is recorded by a sub-rotary magnetic head.
The present invention is characterized in that a digital signal is recorded by a sixth rotary magnetic head in the card band portion between the first tracks formed by the main rotary head.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of the magnetic recording and reproducing apparatus according to the present invention, and FIG. 1 (tz), <h
) is a plan view and side view showing the head cylinder part,
FIG. 2 is a pattern diagram of tracks formed on a magnetic tape, FIGS. 3(α) and (h) are block diagrams showing a recording circuit and a reproducing circuit, and FIG. 4 is an explanatory diagram of recording signals.

In Figures 1 (α) and (h), 1 is a magnetic tape, 2 is a head cylinder, 3 and 4 are tape guides, 5 is an upper cylinder, 6 is a lower cylinder, and 7 is a sub-rotating magnetic head (hereinafter referred to as sub-head). ), 8 is a main rotary magnetic head (hereinafter referred to as the main head), and 9 is a rotary magnetic head for recording and reproducing digital signals (hereinafter referred to as the third head).

In Figure 2, 10.11.12 is a truck;
1 is a magnetic tape shown in FIG.

In FIG. 3(a), 13 to 18 are input terminals, 19° and 20 are time axis compression circuits, 21 is a synthesis circuit, 22 is a frequency modulation circuit (hereinafter referred to as 1M circuit), 23 is an addition circuit,
24 is an analog-to-digital conversion circuit (hereinafter referred to as A/D), 25 is a synthesis circuit, 26 is a modulation circuit, 27 is a clock pilot generation circuit, 2 is a tack generation circuit, 29.
30 is a switch circuit, 31, 32, and 33 are recording amplifiers, and parts corresponding to FIGS. 1(a) and 1(h) are given the same reference numerals.

In Figure 6 <h>, 3A, 35 is a preamplifier, 3
6 is a switch circuit, 37 is a demodulation circuit, 3B is a separation circuit,
39 is a synchronous separation circuit, 4Q, 41.42 is a memory, 4
3 is a clock generation circuit, 44 is a preamplifier, 45 is a demodulation circuit, 46 is a clock extraction circuit, 47 is a phase modulation circuit,
48 is a memory, 49 is a digital-to-analog conversion circuit (hereinafter referred to as D/A), 50, 51, 52 is a band pass filter (hereinafter referred to as BPF), 53 is a detection shaping circuit, 5
4.55 is an envelope detection circuit, 56 is a differential circuit, 57 is a polarity conversion circuit, and 58 to 63 are output terminals.

Now, in Fig. 1 (z), <h), magnetic tape 1
is guided by the tape guides 3 and 4, is wound around the head cylinder 2 in a spiral shape of slightly less than 36 degrees, and travels in the direction of the arrow X. The head cylinder 2 includes an upper cylinder 5 that rotates in the direction of arrow Y and a fixed head cylinder 6. The upper cylinder 5 is provided with a sub-head 7, a main head 8, and a sixth head 9. The main head 8 and the sixth head 9 are arranged in the direction of the arrow Y, and the sixth head 9 is positioned slightly lower @' (that is, in the direction of the lower cylinder 6) with respect to the main head 8. . The sub-head 7 and the main head 8 correspond to the sub-head and the main head, respectively, in the so-called 1.5 head helical force scan system, and are used to perform predetermined recording according to the winding angle of the magnetic tape 1 around the head cylinder 2 and other conditions. It is distributed with a step difference. The main head 8 and the third head 9 have different azimuth angles, and the sub head 7 has the same azimuth angle as the main head 8.

The upper cylinder 5 rotates in synchronization with the field period of the television signal, so that each head 7, 8, 9 scans the magnetic tape 1.

The rotation speed of the head cylinder 2 (more precisely, the rotation speed of the upper cylinder 5, hereinafter referred to as such) is NTSC
For signals, there are 66 oorpm T.

Next, in Figure 2, each of the spatulas mentioned earlier in Figure 1)'
From the arrangement of 7, 8.9 and the direction of rotation of the head cylinder 2 (arrow)', each rotation of the head cylinder 2, the sub head 7 starts scanning the magnetic tape 1, and then the third Head 9 and finally main head 8 start scanning. The sub head 7 corresponds to a 0.5 head in a so-called 1.5 head helical scan system, and records the vertical retrace period of the video signal and some signals before and after the vertical retrace period on the track 11.

The main head 8 corresponds to the main head of the same <1.5 to 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 1.5 x 4.
to be recorded. The above is the same as the so-called 1.5 head heli force scan system.

The sixth head 9 (Fig. 1) is a head for recording and reproducing digital signals, and the height in the direction of the rotation axis is equal to #1 with respect to the main head 8, but it is located below the main head 8. Then, a track 10 is formed by the main head 8, almost overlapping the track 12 formed by the third head 9. Therefore, by appropriately selecting the track pitch of the main head 8, the trunk 12 of the third head 9 can be formed in the guard band portion between the tracks 10 of the main head 8. Further, since the main head 8 and the third head 9 have different azimuth angles, the amount of crosstalk during reproduction between the tracks 10 and 12 can be reduced to a negligible level.

The width of the trunk 12 due to the third head 9 is in this embodiment smaller than the width of the trunk 10 due to the main head 8. B. Even if the S/N ratio when reproducing digital signal sound is lower than that of an analog signal, the digital signal can be reproduced with a sufficient error rate. This is because digital signals such as PCY audio signals generally have a narrower band than analog signals.

Next, the recording circuit shown in FIG. 6(a) will be explained.

In this embodiment, a case where a luminance signal and a color difference signal forming a video signal are time-axis compressed and recorded as a time-axis multiplexed signal is taken as an example.

The luminance signal Y from the input terminal 13 is supplied to the time axis compression circuit 19, and the color difference signal Y from the input terminals 14 and 15 (
7? -1') and (E-Y) are respectively the time axis compression circuit 2
0. The time axis compression circuits 19 and 20 use the horizontal synchronization signal HD supplied from the input terminal 17 and the clock pulse from the clock pilot generation circuit 27 driven by this horizontal synchronization signal HD as a reference, and IH (however, H is The time axis of the signal is compressed by 1 horizontal scanning period), and the time axis compressed luminance signal Y/9 color difference signal (R-)'
)', (B-Y)/ are outputted while being shifted from each other without temporally overlapping.

These luminance signals yt1 color signals (7j-1')/, (B-
1')' (hereinafter, a dash indicates a time-axis compressed signal) is synthesized by a synthesis circuit 21, and these signals are arranged in time series as shown in FIG. 4. A so-called timeplex signal is completely formed.

This time plex signal is subjected to FM modulation by an FM circuit 22, and is supplied to an adder circuit 23, where a pilot signal p for tracking from a switch circuit 27 is added.

The frequency of this pilot signal p is set to be in the lower frequency band outside the frequency band of the FM-modulated time plex signal. 1 clock pilot generation circuit 27 has a different frequency! t/, , f2, and these pilot signals are transmitted to head cylinder 2 (first
The head cylinder 2
is switched every rotation and is supplied to the oi circuit 23.

The output signal of the adder circuit 23 is amplified by a recording amplifier 31, supplied to the main head 8, and recorded on a track 10 shown in FIG. In this case, a pilot signal with a frequency ft is recorded on every other track 10, and a pilot signal with a frequency f is recorded on every other track 10.

pilot signals are recorded.

The output signal of the adder circuit 23 is further transmitted to a switch circuit 30.
supplied to Switch circuit 30 tack generation circuit 28
7, and extracts signals including signals during the vertical retrace period and some periods before and after the vertical blanking period. This extracted signal is recorded amplified 5! The signal is amplified by I, is supplied to the sub-head 7, and is recorded on the track 11 in FIG.

On the other hand, the signal 7 accompanying the television signal from the input terminal 16
The generated audio signal is supplied to the AID 2a and converted into a digital signal based on the clock pulse from the clock pilot generation circuit 27. The digitized audio signal (ie, PCM audio signal) is supplied to the synthesis circuit 25, where it is synthesized with the digital data from the input terminal 18, and an error correction bit is added thereto. Furthermore, the synthesis circuit 25 generates a third signal based on the tack signal from the tack generation circuit 28.
During the period when the head 9 is scanning the magnetic tape 1', P
Time axis compression of the PCM audio signal is also performed so as to output the CM audio signal.

The output signal from the combining circuit 25 is modulated in a form suitable for magnetic recording by a modulation circuit 26, amplified by a recording amplifier 62, and supplied to the third head 9.

Therefore, this PCM audio signal is recorded on track 12 shown in FIG.

As described above, the video signal and the accompanying digital signal are recorded, but when the luminance signal, color difference signal, digital data, etc. to be recorded are combined,
Separate these and input terminals 13, 14, 15, 18 respectively.
1/1° Next, the reproducing circuit shown in FIG. 3(h) will be explained.

The reproduction signals of the main head 8 and the sub-head 7 are transmitted to the preamplifier 5.
After being amplified by 4.35 and then synthesized by the switch circuit 56, the demodulation circuit! 17, and the original time plex signal shown in FIG. 4 is obtained.

This time plex signal is supplied to a separation circuit 38 and a sync separation circuit 39, and the sync separation circuit 39 separates a horizontal sync signal.Based on this horizontal sync signal, a branch circuit 3B converts the time plex signal into time base compression. Luminance signal Y' and color difference signal (R1')/, (B-
Y)' is separated every 1H. These signals are respectively written to the memories 40.41.42 by write clock pulses from the clock extraction circuit A6, and are further read out and time-axis expanded by the read clock pulses to be described later, and sent to the output terminals 5B, 59. 60, the original time axis luminance signal Y1 color difference signal (R)'), (B-1')
is obtained.

On the other hand, the reproduced signal from the sixth head 9 is amplified by a preamplifier 44 and demodulated by a demodulation circuit 45 to become an original digital signal. This digital signal is supplied to a clock extraction circuit 46 and a memory 48. The clock extraction circuit 46 extracts clock pulses from the digital signal. The extracted clock pulse undergoes phase modulation in the phase modulation circuit 47 and is sent to the memory AO,l,A2.48 as a write clock pulse.
supplied to

The clock pulse extracted by the clock extraction circuit 6 has exactly the same time axis fluctuation as the reproduction signal from the main head 8 and the sub-head 7, and for this reason, this clock pulse meeting memo IJ4Q, +11 By using the write clock pulse of A8 as the clock pulse and reading out the clock pulse with a constant repetition frequency from the clock generation circuit 43 and using it as the clock pulse, the memory 40.711./
12. The above-mentioned time axis fluctuations are canceled and not included in each signal read from each of AB.
During the reproduction period of the sub head 7, the digital signal is reproduced from the third head 9 (see FIG. 2), but this period is mainly a vertical retrace period, and the clock extraction circuit 46 has inertia, so there is no problem with abbreviation 11.

In addition, in this embodiment, the main head 8 and the third head 9
Since the azimuth angle is different from the azimuth angle, if there is a deviation in the tracking or tracking of each head 9.8, the time axis will fluctuate.

The phase modulation circuit 47 is intended to eliminate the time axis fluctuations that may cause force, and modulates the phase of the clock pulse from the clock extraction circuit 46 using a tracking error signal, which will be described later, and converts it into a read clock pulse. Including time axis fluctuations caused by tracking deviation, Memo I
J4o, al, 42 are the luminance signal Y1 color difference signal (R-
)') , (BJ) to cancel the time axis shift caused by the tracking shift.

A digital signal is written into the memory 48 using the clock pulses from the clock extraction circuit 46, and is read out using the clock pulses from the clock generation circuit 43 to eliminate time axis fluctuations.

Further, in the memory 48, the digital signal is separated into a PCM audio signal and digital data, and the PCY audio signal is expanded to the original time axis and converted to an analog signal by the D/AA 9, and sent to the output terminal 61. The original audio signal is obtained.

The separated upper digital data is output to the output terminal 61.

As shown in FIG. 2, in the main track 10, every other track has a pilot signal of frequency f, and every other track has a pilot signal of frequency f. .

In this embodiment, as is clear from FIG.
゛Because it is wider than the width, the sixth head 9 also tracks 1oV.
C@e, regenerate the recorded pilot signal. In this case, although the main head 8 and the sixth head 9 have different azimuth angles, the pilot signal has a low frequency and is not affected by the azimuth effect, so the third head 9 also reproduces the pilot signal sound.

Therefore, in FIG. 3(b), the reproduction signal of the third -.rad 9 amplified by the preamplifier 44 is Bl)F51,
52, the BPF 51 separates the pilot signal of frequency f1, and the BPF 52 separates the pilot signal of frequency f. These pilot signals are detected by envelope detection circuits 54 and 55 and supplied to a differential circuit 56 to detect the level difference between the two signals, that is, the amount of tracking deviation.

On the other hand, the signal from the switch circuit 36 has a frequency f.

The output signal of the BPF 50 is supplied to the detection shaping circuit 53, and when there is an input signal of a certain level or higher, a high level signal is output. Therefore, the EPF 50 and The detection and shaping circuit 53 has a function of determining the presence or absence of a pilot signal of frequency fl, and ultimately determines whether the main head 8 is reproducing and scanning a track on which a pilot signal of frequency f is recorded, or a pilot signal of frequency f is detected. It is determined whether a track on which a signal is recorded is being scanned for reproduction.

The output signal of the detection shaping circuit 53 controls the polarity conversion circuit 57. That is, the signal representing the amount of tracking deviation of the differential circuit 56 is generated by the main head 8 reproducing and scanning the track on which the pilot signal of frequency 11 is recorded using the output signal of the detection shaping circuit 53 in the polarity conversion circuit 57. The polarity is set depending on whether the track is being read or scanned by recording a pilot signal of frequency f1, and becomes a tracking error signal that also indicates the direction of tracking deviation.

This tracking error signal is supplied from the output terminal 63 to a tracking servo system (not shown) and, as mentioned earlier, is supplied to the phase modulation circuit 47 to eliminate time axis fluctuations in the reproduced signal caused by tracking deviation. Phase modulation of the clock pulse from the clock extraction circuit 46 is performed.

As described above, one embodiment of the present invention has been described, but according to this embodiment, since the PCM audio signal is recorded on track 12 in FIG. 2, after-recording is difficult. Of course, if only digital data is recorded on the track 12 and the PCM audio signal is recorded on the longitudinal direction of the magnetic tape 1, as in a conventional magnetic recording/reproducing device, after-recording can be easily performed. .

Additionally, as is well known in the past, after-recording can be performed by recording a time-base compressed PCM audio signal in the overlap area. A track pattern of another embodiment of the present invention in this case is shown in FIG.

In the same figure, tracks 65 are provided in the extended portion of the track 11 via some guard portions 64, so that P C' If audio signals without time axis compression can be recorded on these trunks 65. That is, the sub head 7 records the time-axis compressed PCM audio signal following the recording of the video signal. By doing so, only the track 65 can be selectively erased by the preceding erasing head (not shown), making it possible to perform after-recording.

In the above embodiment, the so-called 1,5-head heli force scan system is used, and the sub-head 7, which is a 0.5-head, records and reproduces the vertical blanking period portion of the video signal. In combination with the television camera, the television camera can output the video signal only during the scanning period of the main head 8, and the sub head 7 can be omitted. In this case, the time axis is expanded by using the memory of the playback signal from the main head 8, or by using a playback device that performs playback scanning at a slower speed than during recording, and the time axis is expanded using a normal TV receiver. It can be a video signal that allows image reproduction.

Furthermore, it is also possible to omit the third head 9, to make the azimuth angles of the main head 8 and the sub-head 7 different, and to form the track 12 in FIG. 2 with the sub-head 7. This means that each head 7.8
It can be fruitful by arranging. In this way
.

FIG. 6 shows a further embodiment of the present invention in which a track pattern is formed. In this case, the length of the track 12 is a little more difficult than in the cases of FIGS. 2 and 5, but the time axis compression ratio of the recorded signal can be set accordingly. In addition, in the figure, 66 is a guard portion between the recording portions of the video signal and the digital signal.

〔Effect of the invention〕

As explained above, according to the present invention, a digital signal such as a PCM audio signal accompanying a television signal can be recorded between tracks on which a video signal is recorded. Digital signals can be recorded and reproduced independently, and signal processing during recording and reproduction is easy, and each signal can be recorded under optimal conditions. Since the amount of winding can be reduced, the recording density of the magnetic tape can be improved, and a magnetic recording/reproducing device with excellent functions can be provided without the drawbacks of the above-mentioned prior art.

[Brief explanation of drawings]

1 to 4 show an embodiment according to the present invention, in which FIGS. 1(α) and (b) are a plan view and a side view showing the head cylinder portion, and FIG. 2 is a magnetic tape Is the track pattern diagram formed above, Figure 3(a), the recording circuit? FIG. 3 is a block diagram showing the reproducing circuit, FIG. 4 is an explanatory diagram of the recording signal, and FIG. FIG. 6 is a pattern diagram of tracks formed on a magnetic tape in still another embodiment of the magnetic recording/reproducing apparatus according to the present invention. 1...Magnetic tape 2...Head cylinder 7...Sub-rotating magnetic head 8...Main rotating magnetic head 9...Third
Rotating magnetic head (Representative Patent Attorney Akio Takahashi Figure 5 (l:11) Class 4 Figure 5 Figure 6 Figure 6 Continued from page 1 0 Inventor Shiba 1) Akira Yokohama City Totsuka Ward - Research Institute

Claims (1)

[Claims] In a magnetic recording and reproducing device equipped with a main rotary magnetic head and a sub-rotary magnetic head, the main rotary magnetic head records most of the video signal accompanying a television signal on a first track, and the remaining part is recorded on a first track. The second rotating magnetic head
The first track and the second track are formed separately in the width direction of the entire magnetic tape, and the television signal is recorded on the inter-track guard band portion of the first track. A magnetic recording/reproducing device characterized in that a third track is formed for recording an accompanying digital signal.