JPS6280874A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain high definition reproduction and accurate after recording by sectioning a track of a magnetic tape into plural fields, recording a digital signal on them, reproducing the signal from the inner field and recording the signal on the outer field. CONSTITUTION:An oblique track is formed in the lengthwise direction of a magnetic tape by a rotary magnetic head. One track having a length corresponding to a winding angle of 221 deg. is sectioned into 4 fields A-D each having a length of 54 deg.. In recording a digital signal while audio signals F, B are added before and after stereo audio signals L, R so as to digitize a 4-channel signal, the left/right signals L, R and the forward/backward signals F, B are recorded on the inner fields B, C as a pair in the 1st recording. The digital signal is reproduced from the fields B, C and the signals L, R and the signals F, B are recorded at the 2nd recording while the outer fields A, D are used as a pair. Thus, high definition reproduction and after recording are executed accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording/reproducing device 1Tt for recording and reproducing information on and from a rotating magnetic field such as a video tape recorder.

[Summary of the invention]

The present invention provides a magnetic recording+lG production device that records and reproduces information by winding a magnetic tape at least 180 degrees around a rotating drum having a magnetic head, with two rotations Ilr+ separated by 180 degrees from each other, with respect to the longitudinal direction of the magnetic tape. The track formed at an angle is divided into multiple areas, and an analog signal is sampled using a clock of a predetermined frequency and recorded in the area as a digital signal, and the digital signal recorded in one area is reproduced and transmitted to another area. When recording in the O(i it) area, it is played back from the inner area and recorded in the outer area, allowing you to enjoy higher quality audio signals etc. on an 8m video tape recorder etc. In addition, the signal reproduced by one rotary magnetic head can be accurately recorded by the other rotary magnetic head.

[Conventional technology]

Recently, the so-called 8nn video tape recorder has been standardized,
It has been commercialized. In this 8 mm video tape recorder, the rotating diameter of the rotating magnetic head (the diameter of the rotating drum) is 40 nn, and the winding angle of the magnetic tape around the rotating drum is 221 degrees.

The part corresponding to the winding angle of 180 degrees receives the video signal, and the part corresponding to the winding angle of 36 degrees receives the P signal.
A CM audio signal is recorded (the remaining 5th part is considered as a surplus). If we divide this 36 degree portion into more detail, there is a portion a where a clock signal is recorded and a portion where data such as a PCM audio signal is recorded.

It is divided into a margin section C for after-recording and a video overlap section d where the video signal of the immediately previous field is continuously recorded. and for the entire part corresponding to the winding angle of 221 degrees.

Tracking pilot signals f,, f2. f3, f
4 are sequentially recorded on each track. These pilot signal fs, f2. f, , f4 are each, for example, f
58, fH150, f, /36, fll/4.0 (f
H is a horizontal synchronization signal). A tracking error signal is generated from crosstalk components from the left and right tracks of the pilot signal continuously recorded on each track. The rotation speed of the rotating magnetic head is 1800 ppm in the NTSC system, since it records video signals.
In the PAL system, it is set to 1500 ppm. Furthermore, a plurality (5) of parts corresponding to a winding angle of 36 degrees are formed in the part corresponding to a winding angle of 180 degrees, so that only audio signals can be recorded.

The audio signal recorded in the 36 degree area has a sampling frequency of 2fH (approximately 31.5 degrees) and a quantization bit count of 10 bits (however, on the magnetic tape, 10 bit data is converted to 8 bits). (compressed) and recorded)
, the number of channels is 2.

On the other hand, R-DAT has recently been standardized in order to record and reproduce audio signals on magnetic tape with even higher quality.

In R-DAT, the winding angle of the magnetic tape is 90 degrees, the diameter of the drum per rotation is 30 m, and the sampling frequency is 48 to 7, 44.1 to 7, and 32 k.
For any of I[z, the number of quantization bits is 16 bits and the number of channels is 2.

The track corresponding to the winding angle of 90 degrees is divided into 16 parts as shown in FIG. 4, and data is recorded in each part as shown in Table 1. Here, one block consists of 288 bits of data.

On magnetic tape, 8-bit data is converted to 10-bit data (
modulated) and recorded.

Note that fch is a clock signal with a frequency of 9.408 MHz.

As can be seen from Table 1, this data mainly consists of parts 2.3.
4, a tracking signal recording section consisting of section 5.6.7, a PCM audio signal recording section consisting of section 8.9, and section 10.11.12.
Tracking signal recording section and one part consisting of 13.14.
15 subcode signal recording sections.

[Problem that the invention seeks to solve]

There are two methods for recording and playing back digital audio signals on magnetic tape using a rotating magnetic head, but the 8m video tape recorder is originally designed to record video signals, so it is possible to record and play back digital audio signals on magnetic tape. The sampling frequency was also low, and the sound quality was inferior to that of R-DAT.

[Means for Solving the Problems] FIG. 1 shows a block diagram of a magnetic recording and reproducing apparatus (8-field video tape recorder) of the present invention.

In the same figure, 1 is a rotating drum (180 degrees apart from each other).
(not shown), the rotary magnetic head 1 is alternately supplied with signals from the recording amplifier 4 via a switch 2.3, and the signal from the rotary magnetic head 1 is The signal is output to a regenerative amplifier 5 via switches 2 and 3. The recording amplifier 4 is supplied with signals from a video modulator 8 and a PCM encoder 9 via a switch 6, and is also supplied with a pilot signal output from a pilot signal generator 35. Further, the signal from the regenerative amplifier 5 is outputted to a video demodulator 10 and a PCM decoder 11 via a switch 7. 12 and 13 are a PCM decoder and a PCM encoder compatible with the R-DAT format; the signal from the regenerative amplifier 5 is supplied to the PCM decoder 12 via the switch 7, and the output of the PCM encoder 13 is supplied via the switch 6. The signal is then supplied to the recording amplifier 4. 14 generates a clock signal f'ch and PCM
This is an oscillator outputting to the encoder 13.

Reference numeral 15 denotes a motor that rotates the rotating drum, and includes a frequency generator 16 and a pulse generator 17, and a drive circuit 18.
is driven by. The output of the frequency generator 16 is input to a frequency control circuit 19, and is compared with a predetermined reference signal output from a built-in oscillation circuit. Frequency control circuit 19 outputs the error signal. 20 is a phase control circuit;
A vertical synchronization signal included in the recorded video signal separated by the synchronization separation circuit 22, a reference signal outputted by the oscillator 23, a reference signal outputted by the PCM decoder 12, or P
Either of the reference signals output by the CM encoder 13 is
It is input as a reference signal via switch 21.

The phase control circuit 20 compares the phases of the pulses output by the pulse generator 17 and the reference signal, and outputs a signal corresponding to the error. The output of the frequency control circuit 19 and the output of the phase control circuit 20 are added by an adder circuit 24 and supplied to the drive circuit 18.

25 is a motor that rotates a capstan (not shown), and is equipped with a frequency generator 26.

The output of the frequency generator 26 is supplied to a frequency control circuit 27 and a frequency dividing circuit 28. The frequency control circuit 27 uses a predetermined reference signal output from a built-in oscillation circuit and the frequency generator 2.
It compares the output of G and outputs the error signal to the adder circuit 30. The frequency dividing circuit 28 divides the frequency of the output of the frequency generator 26 and outputs the divided signal to the phase control circuit 29 . The phase control circuit 29 compares the signal from the switch 21 and the signal from the frequency divider circuit 28 and outputs the error signal to the adder circuit 30 via the switch 34. The adder circuit 3° adds the output of the frequency control circuit 27 and the output of the phase control circuit 29, and outputs the result to the drive circuit 31.

The drive circuit 31 is configured to drive the motor 25. 32 is a tracking control circuit, which separates and extracts the piezot signal from the output of the regenerative amplifier 5, generates a tracking error signal, and sends the tracking error signal to the adder circuit 3o via the switch 34.
It is output to. Reference numeral 33 denotes a central processing unit (CPU) such as a microcomputer, which controls each circuit 1 means, switches, etc. in conjunction with a main central processing unit (not shown).

[Effect]

The effect will now be explained. When a command to record a normal video signal and an accompanying PCM audio signal is input, the CPU 33 controls the frequency control circuit 19.27,
A control signal is sent to the drive circuit 18.
rpm (1500 rpm in the case of the PAL system), and the capstan is rotated by the motor 25 so that the speed of the magnetic tape (not shown) becomes the standard speed.

At this time, the frequency control circuit 19 applies servo so that the frequency of the signal output by the frequency generator 16 becomes equal to the frequency of the built-in reference signal. At this time, the switch 21 is switched to select the output of the synchronization separation circuit 22, and the rotary drum is rotated so as to be synchronized with the phase of the vertical synchronization signal in the video signal to be recorded. The phase control circuit 20 generates a hent switching pulse (H5WP) that serves as a reference for switching between the two rotating magnetic heads, and outputs it to each circuit.

Similarly, frequency servo and phase servo are applied to the motor 25 by the frequency control circuit 27 and the phase control circuit 29. At this time, the phase control circuit 29 uses the output of the synchronous separation circuit 22 outputted by the switch 21 as a reference, and supplies an error signal between the output of the frequency dividing circuit 28 and the output to the addition circuit 30 via the switch 34. Therefore, the predetermined speed (14 in the case of NTSC system)
．． 345nwn/s, 20.051m for PAL method
The speed of the magnetic tape is controlled so that the speed of the magnetic tape is 100 m/s).

The video signal to be recorded is input to a video modulator 8 and frequency modulated. Also, the recorded audio signal is
The signal is input to the M encoder 9 and digitized (PCM). These signals are passed through a switch 6 to a recording amplifier 4.
, further supplied to the rotary magnetic head 1 via the switch 2.3, and recorded on the magnetic tape. Phase control circuit 20
1 based on the head switching pulse output by
A video signal is recorded in the 80-degree video signal recording section, and an audio signal is recorded in the 36-degree audio signal recording section. Also, at this time, a tracking pilot signal generated by the pilot signal generator 35 is frequency-multiplexed with the video signal and the PCM audio signal and recorded. Its frequency can be the same as the pilot signal in the case of the PAL system. In this way, the clock signal f
'ch or L] It becomes easy to frequency divide and generate the pilot signal.

When reproducing a video signal, the output signal of the oscillator 2:3 (signal corresponding to the vertical synchronization signal) is supplied to the phase control circuit 20 as a reference signal via the switch 21. Further, the switch 34 is switched to the tracking control circuit 32 side, and the phase servo of the motor 25 is performed in response to the tracking error signal generated from the crosstalk components of the pilot signals recorded on the left and right adjacent tracks.

The reproduction signal from the rotating magnetic head 1 is transmitted to the video demodulator 10 and P via the switch 2.3, the reproduction amplifier 5, and the switch 7.
The CM decoder 11 is manually operated. Therefore, the video signal recorded in the 180-degree video signal recording section and the audio signal recorded in the 36-degree audio signal recording section are each demodulated and output.

Next, when recording only high-quality audio signals, the audio signals are input to the PCM encoder 13 and digitized. The PCM encoder 13 is a so-called R-DAT.
The same PCM encoder as can be used. However, the PCM encoder 13 is controlled at a different timing by a different clock than in the R-DAT.

That is, in the present invention, one track having a length corresponding to a winding angle of 221 degrees has a length of 54 degrees as shown in FIG.
Divided into four areas of degree length.

Extra portions of 2.044 degrees and 2.956 degrees are provided on the left and right sides thereof. The area A to the second table having a length of 54 degrees is divided into nine parts as shown in FIG. 3, and data is recorded in each part as shown in the second table.

As is clear from Table 2, in the present invention, the tracking data recording units 5, 6, 7 and 10 in Table 1
．． 11.12. In particular, the format is such that the last margin section 16 is removed. Further, the clock f'ch here is, for example, 12.864 MHz (=160
．． 8X288X (10/8)10.0045). Of course, the combination can be changed as long as the winding angle of 54 degrees and the recording time of 4500 μs are maintained.

For example, it is possible to eliminate the two-block PLL (PCM) clock recording section and change the margin section from 8.8 to 10.8 blocks.Furthermore, the remaining sections at both ends can be arbitrarily selected.

In this way, R-DA, which has already been standardized,
Information can be recorded and reproduced simply by changing the timing without changing the coding of the T format.

The audio signal input to the PCM encoder 13 is 1
Clock input from the oscillator 14 (ii X>f'c
digitized corresponding to h, and the timing is CP
It is controlled by tJ 33 and converted into a signal having the format shown in Table 2. This (i is switch 6
, a recording amplifier 4, and switches 2, ;3, the signal is supplied to the rotary magnetic head 1 and recorded on the magnetic tape. Based on the head switching pulse outputted by the phase control circuit 20 at this time.

An area pulse corresponding to at least one of the areas @A to A is generated, and a signal is recorded in the area corresponding to the area pulse.

At this time, the frequency control circuit 19 and the drive circuit 1 are controlled by the CPU 33 to rotate the rotary drum at 200 rpm. Further, the switch 21 supplies a signal synchronized with the clock f'eh output from the PCM encoder 13 to the phase control circuit 2o as a reference signal. Furthermore, the frequency control circuit 27 and the drive circuit 3] are controlled in the same manner, and the speed of the magnetic tape is adjusted to the standard speed of PAL system 20.051 mm/
Set the speed 1' to 0.025 nm/s, which is 1/2 of s.

When set to this speed, the track pitch becomes 13.3 μm, and the rotating magnetic head for the standard speed of the NTSC system or the rotating magnetic head for 1/2 speed of the standard speed of the NTSC system, and the rotating magnetic head for the 1/2 speed of the standard speed of the PAL system. The width of the head falls within a range that allows recording and reproduction of audio signals and pilot signals, as well as tracking control based on the crosstalk component of the pilot signal, eliminating the need to use a rotating magnetic head with a special width.

When reproducing an audio signal recorded in this quality, a signal from the rotating magnetic head 1 is inputted to the reproducing amplifier 5 via the switch 2.3, and further supplied to the PCM decoder 12 via the switch 7. PCM decoder 1
2 is controlled by the CPU 33 and generates the clock f' from the reproduction signal.
Extract the channel and read the data of each part using it as a reference. The audio signal is converted into an analog signal and output. Further, a pilot signal for tracking included in the reproduced signal is input to the tracking control circuit 32,
A tracking error signal is generated.

This tracking error signal is output to the adder circuit 30 via the switch 34, and tracking control is performed.

In other words, in R-DAT, as is clear from Table 1, a tracking signal (ATF) is recorded before and after the PCM audio signal recording section, and crosstalk components from that part of the left and right trunks are recorded. A sample is held at a predetermined timing, and a tracking error signal is generated from the difference signal.5 In the present invention, as in the case of a normal 8nwn video tape recorder, the tracking error signal is continuously recorded on each track. A tracking error signal is generated from the difference signal of the Talostok components from the left and right tracks of the pilot signal.

Next, the data to be recorded in each area A through can be configured as shown in Table 3, for example. That is, when recording information is a stereo audio signal, R is assumed, and the sampling frequency is 48 kIlz.

A predetermined number of data sampled by each clock (
If consecutive numbers are assigned to words), Table 3 shows the odd-numbered numbering signal (Lo) and the even-numbered R signal (Re).
is in area A, odd numbered R signal (Ro) and even numbered 17
A signal (Le) is recorded in each area A of the next adjacent track. That is, the data is interleaved on two tracks (with further interleaving within each track), and by obtaining the signals of the two tracks, complete data can be reproduced. Of course, if the advantage of using the same encoder and decoder as R-DAT is abandoned and a different encoder and decoder is used, such interleaving can be set arbitrarily. Similar records are in each area B and C.

In this case, information of two channels (L, R) can be recorded four times on one inclined track. Note that in Table 3, only data LO and Re are listed for convenience (the same applies hereinafter).

Set the sampling frequency to 9, which is twice the reference frequency of 48kHz.
6k) When tz, first the even numbered signal Le.

Re, and odd numbered signals Lo and Ro.

Then, a new order is assigned to the even-numbered signals Le and Re, and the same classification as described above is performed for the new order. That is, a new signal Lo having an odd number i1 and a signal Re2 having an even number are recorded in area A, and a new signal Ro2 having an odd number in order and a signal Le having an even number are recorded in the next adjacent area A. Then, a new order is added to the signals Lo and Ro whose original order is an odd number, and the signals are processed in the same way, but these signals are recorded across the area.

As a result, the signal recorded in each area is essentially 48kll.
It is similar to the signal sampled at z, and is 48k)
When decoded with the lz clock decoder, it is 48kHz.
It is possible to reproduce the same audio signal as when sampling with z. This becomes impossible if, for example, one piece of sampling data is divided into upper bits and lower bits and each bit is recorded in a different area.

Furthermore, the sampling frequency is set to 192, which is four times the reference frequency.
When converting to k Ilz, data is first divided into data groups of every 4 samples. For example, as shown in FIG.

Sampling value L L , l R1 at time tit
1 and.

Sampling values L2□, R21 after 4 clocks
Then, the sampled value L after 4 clocks
3. , R,1, etc. are one group. Similarly, the sampling value L, 2. R02, L2□, R2□
, L, , R, □, etc. are set as one group, and the sampling value is □,
.

Ryu1, L23. R2,,L33? R33 etc. 1
group, sampling value L 141 Rl 4, L24
．． R, go, 4. R34 etc. are considered as 1 group. Then, the same processing as described above is performed so that each of these four groups is recorded in a different area A to each other. For example, if a new order is assigned within the first group, the odd numbered signal L04. and even numbered signal Re4 are recorded in area A, and odd numbered signal Ro4° and even numbered signal Le4 are recorded in the next adjacent area A, respectively. As a result, in this case as well, as in the case described above, the signals recorded in each area are essentially equivalent to the signals sampled with the reference frequency clock, and reproduction using the reference frequency decoder becomes an i-process. .

Similarly, if data is divided into data groups of every two samples, reproduction using a decoder with a frequency twice the reference frequency becomes possible.

Therefore, in any case, it is clear that it is preferable to make the recording area compatible with a lower sampling frequency.

Next, a case will be described in which, for example, front and rear audio signals (F, B) are added to the stereo audio signal (L, R) to record a four-channel audio signal. In this case, when the sampling frequency is set to the reference frequency of 48 kHz, left and right stereo signals (L, R) are sequentially recorded in area A, and corresponding front and rear signals (F, B) are recorded in area B, respectively. In principle, left and right audio signals (L
.

It is also possible to record audio signals (F, B) before and after (R) in one area. However, if you do that, you will have two channels of stereo signals (left and right signals (L, R).
))L, or playback becomes impossible on devices that cannot play. Therefore, the left and right signals (L, R) and the front and rear signals (F
, B) are preferably recorded in different areas. Left and right signals (L.

R) and front/rear signals (F, B) can be recorded in any area; the former can be recorded in areas B and A, and the latter can be recorded in areas C and D.
You can also record it in

In this case, since the left and right signals (L, R) and the front and back signals (F, B) can be recorded in areas C and D, respectively, information is recorded twice on one inclined track. In the above, the odd numbered signal Lo (Fo) and even numbered signal Re (Be) are recorded first in each area, and the odd numbered signal R is recorded in the next adjacent area.
o (Bo) and the even numbered signal Le (Fe). In this case, it is possible to arbitrarily decide in which area the left and right signals, R, and the front and rear signals F and B are to be recorded. The area where left and right signals and R are recorded is the area where 2 channel stereo signals are recorded, the area where R is recorded first, or the area where R is recorded first.
It is preferable that the two-channel stereo signal with a sampling frequency of 6 kHz is made to correspond to the area in which R is recorded first or next.

96 times the standard frequency of the 4-channel audio signal
When sampling with kl[z, the sampling values are first divided into odd-numbered sampling values , R, , F, , B, and even-numbered sampling values Le, Re, Fe, and Be. And the odd number signal L0. RD + Fa e
A new order is given to each of the signals Le, Re, Fe, and Be at even numbers. Odd number signal L0. A signal Lo4 whose new order is an odd number among Ro,
The signal Re4 whose new order is an even number is added to the area A, and the signal Ro whose new order is an odd number among the odd number signals, , and Ro.
4 and a new even-numbered signal Le4 are recorded in the next adjacent area A. Similarly, signals Fo and B at odd number of shiso
, the signal F04 whose new order is an odd number and the signal Be4 whose new order is an even number are in the area B, and the odd number signal F,
,B. Of these, the signal BO4 whose new order is an odd number and the signal Fe4 whose new order is an even number are recorded in the next adjacent area B. Even-numbered signals Le, Re, Fe,
Be is recorded in areas C and D in the same way. In this case as well, the areas for recording left and right signals, R, and front and rear signals F and B can be set arbitrarily, but in the case of standard frequency 2-channel stereo recording and standard frequency 4-channel recording It is preferable to make it correspond to That is, for example, the left and right signals of the sampling value of
The left and right signals of the sampling value of z, R, and 48k)
The preceding and following signals F and B of the sampling value of 96kHz are recorded in the same area as the area where the preceding and following signals F and B of the sampling value of Iz are recorded.

Record each item B. By doing this, 48
Even in a device having only a sampling clock of kIk, it becomes possible to reproduce a signal with a sampling value of 96k)Iz. In this case, one inclined track has one
times information will be recorded.

It is clear that if the recorded information is made into mutually independent information S to Z, eight channels of information can be recorded with 48 kHz sampling.

When it is necessary to further lengthen the recording wavelength.

Areas A and B may be used as one area, and areas C and D may be used as one area.

The above description has been made assuming that the regions A to A are equivalent.

However, in reality, when recording and reproducing information using two rotating magnetic heads rotated 180 degrees apart from each other, areas A or D
In this case, when one rotating magnetic head is in contact with the magnetic tape, the other rotating magnetic head is also in contact with the magnetic tape. As a result, when one rotary head plays back information and the other rotary head records information (for example, after-recording), the information on one side overlaps with the other information, noise increases, and the accuracy is reduced. It may become difficult to record and reproduce information. Therefore, when reproducing information using one rotary head and recording information using the other rotary head, it is preferable to reproduce information from areas B or C located in the center and record to area A or D. . Therefore, for example, when recording four channels of audio signals using standard frequency sampling, it is preferable to pair areas A and D or areas B and C, but in order to further enable after-recording, one For example, during the first recording, the front and rear signals F and B are recorded on the left and right signals I, , l;: , using the inner areas B and C as a pair, and during the second recording, the outer areas A and D are recorded as a pair. It is preferable to record the left and right signals, R, and the front and rear signals F and B as a pair.

Next, an embodiment of the PCM encoder 13 will be described.

For example, as shown in FIG.
It can be configured by a D converter 41 and a memory 42. The A/D converter 41 receives the input left and right signals, R,
Converting an analog signal to a digital signal according to a clock of a predetermined frequency (96klLz in the example),
It is stored in the memory 42. The signals stored in the memory 42 are read out according to a clock of the same frequency. At this time, for example, if the data read out at odd-numbered clocks is recorded in area A, and the data read out at even-numbered clocks is recorded in area B, the data recorded in each area can be sampled. The frequency is 48kl
(becomes z.

Further, the same thing can be realized in an embodiment as shown in FIG. That is, preferably in this embodiment, the A/D converter 41 operates with a clock of 48k)Iz.
Two systems (A, B) of memory 42 are prepared. The A/D converter 41B and the memory 42B are supplied with the 48 & clock (FIG. 8(b)) supplied to the A/D converter 41A and the memory 42A by the delay circuit 43.
The signal is supplied with a delay of 100 degrees (FIG. 8(C)). Therefore, for example, a predetermined analog signal (FIG. 8(a)) is sampled by 48 kHz sampling pulses whose phases differ by 180 degrees, and each signal is recorded in areas A and B. As a result, the original signal is substantially equivalent to being sampled at a frequency of 96 kHz.

FIG. 9 shows a PCM decoder 12 that decodes such a signal.
represents an example of In this example, the reproduced signals from areas A and B (48K signals with a phase shift of 180 degrees from each other) are used.
The signals sampled by the Hz clock) are added by the adder circuit 51 to become substantially 96kl (z sampling signals), and then input to the D/A converter 52. A 96 kHz clock is input, and a digital signal read out according to this clock is smoothed by a low-pass filter 53 and output as an analog signal.

FIG. 10 shows another embodiment of the PCM decoder 12. In this embodiment, there are two systems M (A.

B) It is prepared. The outputs of the D/A converters 52A and 52B are supplied to a sample hold circuit 54, and the output thereof is further output to a low pass filter 53. D/A
A 48 kHz clock is input to the converter 52A, and the clock is input to the D/A converter 5213 after being delayed by 180 degrees by the delay circuit 55. Further, a clock delayed by 180 degrees from this clock is supplied to a sample hold circuit 54. For example, the reproduced signal from area A is converted from a digital signal to an analog signal by the D/A converter 52A (shown by a solid line in FIG. 11), and the +IF raw signal from area B is converted from a digital signal to an analog signal by the D/A converter 52A.
The digital signal is converted into an analog signal by the converter 52B (indicated by a broken line in FIG. 11), and then input to the sample and hold circuit 54. Sample hold circuit 5
4 is a non-delayed clock that sequentially samples and holds the output of the D/A converter 52A, such as L//'C ax l 21 a3, and also samples and holds the output of the D/A converter 52B in response to the delayed clock. Levels b, b2, etc. are sampled and held sequentially. The combined output is smoothed by a low-pass filter 53, and the original signal (indicated by a dashed line in FIG. 11) is reproduced.

In this way, 2 48kllz encoders or decoders
If you prepare a system, 96k) (Effectively 96k even if you do not prepare the z clock and its encoder or decoder) I
The sampling signal of z can be recorded and reproduced.

In addition, the signals encoded by the encoder as described above and recorded in each area A or A are reproduced for each area, and 48
Of course, it is possible to reproduce a 48kllz sampling signal by decoding it with a k)Iz decoder.

〔effect〕

As described above, the present invention provides a magnetic recording and reproducing apparatus that records and reproduces information by winding a magnetic tape 180 degrees or more around a rotating drum having two rotating magnetic heads rotated 180 degrees apart from each other. The track formed at an angle to the other area is divided into multiple areas, and an analog signal is sampled with a clock of a predetermined frequency and recorded in the area as a digital signal, and the digital signal recorded in any area is reproduced. When recording in other areas,
Since playback is performed from the inner area of the area and recording is made to the outer area, it is possible to enjoy higher quality audio signals on 8 nm video tape recorders, etc. When the reproduced signal is recorded by the other rotating magnetic head (after-recording), noise and therefore errors can be reduced, making accurate recording possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the magnetic recording/reproducing apparatus of the present invention, and FIG.
The figure is a schematic plan view of the track, FIG. 3 is a schematic plan view of the area, FIG. 4 is a schematic plan view of the track in a conventional magnetic recording/reproducing device, and FIGS. 5 and 8 are according to the present invention. 6 and 7 are block diagrams of its pcM encoder, FIGS. 9 and 10 are block diagrams of its PCM decoder, and FIG. 11 is a schematic diagram of its output signal. FIG. 1...Rotating magnetic head 2.3, 6, 7, 21, 34...Switch 4...Recording amplifier 5...Reproducing amplifier 8...Video modulator 9.13...PCM encoder 10 ... Video demodulator 11.12 ... PCM decoder 14.23 ... Oscillator 15.25 ... Motor 16.26 ... Frequency generator 17 ... Pulse generator 18.31 ... Drive circuit 19.27... Frequency control circuit 20.29... Phase control circuit 22... Synchronization separation circuit 24.30... Addition circuit 28... Branch circuit 32... Tracking control circuit 33... ... Central processing unit 35 ... Pilot signal generator 41 ... A/D converter 42 ... Memory 43.5
5...Delay circuit 51...Addition circuit 52...D/A converter 53.
...Low pass filter 54...More than sample hold circuit

Claims (1)

[Scope of Claims] A magnetic recording and reproducing device that records and reproduces information by winding a magnetic tape by 180 degrees or more around a rotating drum having two rotating magnetic heads spaced apart from each other by 180 degrees, with respect to the longitudinal direction of the magnetic tape. The track formed at an inclination is divided into a plurality of areas, and an analog signal is sampled with a clock of a predetermined frequency and recorded as a digital signal in the area, and the digital signal recorded in any of the areas is reproduced. 1. A magnetic recording and reproducing apparatus characterized in that when recording in another area, reproduction is performed from the inner area of the area, and recording is performed in the outer area.