JPH03201885A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To simplify the circuit constitution by applying pulse mode modulation (PCM) processing to an audio signal at recording and superimposing an audio PCM signal onto a time compressed integration (TCI) signal of each channel for the vertical blanking period. CONSTITUTION:An audio PCM signal is superimposed on a TCI signal for the vertical blanking period so as to use a modulator, demodulator and a head peripheral circuit or the like for processing of a video signal provided originally in common for the processing of the audio PCM signal. Moreover, a time axis error correction means 20 to correct a time axis error of the reproduced TCI is provided and when the reproduced TCI signal is detected in the case of sampling the reproduced TCI signal by an A/D converter 21 of the time axis error correction means 20, the audio PCM signal superimposed on the reproduced TCI signal is simultaneously detected.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to a so-called video tape recorder (hereinafter referred to as VT).
Regarding magnetic recording and reproducing devices such as PCM (Pulse Code Modular
The present invention relates to a magnetic recording and reproducing device for recording and reproducing (on) signals.

[Conventional technology]

In recent years, along with the demand for higher quality television images, the demand for higher quality audio has also increased.As a measure to achieve higher sound quality, video is being developed that converts audio signals into digital signals and converts them into PCM signals for recording and playback. Signal recording and reproducing devices have been developed. For example, the 8mm video system is known for NTSC signals, and the UNIHI system is known for high-definition signals.

For example, recording methods for these audio PCM signals include:
As shown in FIG. 17, the tape pattern of the UNIHI system (a professional HDTV baseband VCR using 1/21 nch tape) includes tracks 82, 82, . . . (track width: 20) for recording video signals on a magnetic tape 81.
．． 0 .mu.m, track pitch: 24.degree. 8 .mu.m), and tracks 83, 83, . Note that the track 8 at one end in the width direction of the magnetic tape 81
4 (width 0.60 μm), an audio signal is recorded, track 85 (width 0.40 μm) at the other end in the width direction records a control signal, track 86 (width 0.45 μm)
m) is designed to record a time code.

Next, FIG. 18(a) shows a block diagram of signal processing in a recording system of a conventional video signal recording/reproducing apparatus. After the video signal is converted into a digital signal by an A/D converter 87, it is converted to a TCI (time signal) by a TCI encoder 88.
Compressed Integration) signal, and is further FM modulated by an FM modulator 89,
The data is recorded on the magnetic tape 81 by a magnetic head 91 via a recording amplifier 90.

On the other hand, the audio signal is converted into a digital signal by an A/D converter 92, added with an error correction code generated by an error correction code generation circuit 93, and then modulated by a modulator 94 to become a PCM signal. The data is recorded on the magnetic tape 81 via the magnetic tape 81.

Further, the playback system of the video signal recording and playback device is configured as shown in FIG. After that, it is demodulated by the FM demodulator 103. And TBC (Time Ba5e Co.
time axis correction is performed in 104, and the TCI
After the TCI signal is converted into a high-definition video signal by the decoder 105, it is outputted via the D/A converter 106.

On the other hand, the audio PCM signal reproduced from the magnetic tape 81 is amplified by a reproduction amplifier 107, waveform-equalized by an equalizer 108, and then pulse detection and synchronization based on the detection and synchronization circuit 109 are performed. And demodulator 110
The signal is demodulated by the code correction circuit 111, and code errors are corrected as necessary by the code correction circuit 111, and then outputted via the D/A converter 112.

[Problem to be solved by the invention]

As mentioned above, in the conventional video signal recording and reproducing apparatus for recording and reproducing audio PCM signals, the tracks 83 and 83 in FIG.
83..., not only a track dedicated to the audio PCM signal is required, but also a dedicated equalizer 108 for recording and reproducing the audio PCM data on the magnetic tape 81 (FIGS. 18(a) and (b)). , a detection/synchronization circuit 109, etc. are required, which poses a problem of complicating the circuit configuration.

[Means to solve the problem]

In order to solve the above problems, the magnetic recording and reproducing apparatus according to the present invention has two channels of high-definition video signals and 1125H (56
2.5H/CH) is converted into a TCI signal and then recorded on a magnetic tape using a helical recording method using a rotating head, while the TCI signal reproduced by the rotating head is decoded and output from the magnetic tape. In a recording/playback device, an audio signal is subjected to PCM processing at the time of recording, and this audio PC
The basic feature is that it includes an audio PCM signal superimposing means for superimposing the M signal on the vertical retrace period of the TCI signal of each channel.

The magnetic recording/reproducing device has a built-in A/D converter and detects the reproduced TCI signal based on the detection of the reproduced TCI signal.
It is preferable to include a time axis error correction means for correcting a time axis error of the reproduced TCI signal on which the audio PCM signal is superimposed by sampling the I signal with the A/D converter.

Further, the audio PCM signal superimposing means
TC the 2 bits of the audio PCM signal before superimposing it on the CI signal.
It is preferable to include a modulation circuit that modulates into four patterns represented by three I clocks, and a demodulation circuit that demodulates the audio PCM signal modulated into the four patterns during reproduction.

[Function] According to the above configuration, since the audio PCM signal is superimposed on the vertical retrace period of the TCI signal, the modulator, demodulator, and head surroundings that are originally provided for processing the video signal are used. Circuits (recording amplifier, equalizer), etc. can be shared for processing audio PCM signals, thereby simplifying the configuration and reducing the number of parts. Also, audio P
By superimposing the CM signal on the vertical retrace period of the TCI signal, the area of the magnetic tape required for signal recording can be reduced, and as a result, the storage capacity can be increased.

Furthermore, as described above, if the time axis error correction means for correcting the time axis error of the reproduced TCI signal is provided, when the reproduced TCI signal is sampled by the A/D converter of the time axis error correction device, the reproduced TCI signal is When detected, the audio PCM signal superimposed on the reproduced TCI signal is also detected at the same time.

Therefore, there is no need to separately provide a pulse detection circuit and a reproduction clock generator exclusively for the audio PCM signal.
The number of parts can be reduced.

Furthermore, as described above, the audio PCM signal superimposing means is provided with a digital modulator to convert the 2 bits of the audio PCM signal into 4 patterns represented by 3 clocks of the TCI clock before superimposing the audio PCM signal on the TCI signal. Along with modulating,
By demodulating the audio PCM signal modulated into the above four patterns with a digital demodulator during playback, the waveform distortion and waveform that are likely to occur when the audio PCM signal is FM modulated and recorded as is, similar to the TCIC signal medium image signal, can be demodulated. By alleviating the influence of interference, it becomes possible to properly detect the audio PCM signal during playback.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 16.

As shown in FIG. 3, a video signal recording and reproducing device as a magnetic recording and reproducing device is equipped with a rotary head drum l (Japanese Patent Application No. 1-1580 filed by the applicant on June 20, 1999).
75), and the rotary head drum 1 is provided with two magnetic head groups X and Y each consisting of four magnetic heads (rotary heads) 2 to 5 and 6 to 9. Two corresponding magnetic heads in head group X-Y, for example, magnetic heads 2 and 5, are each arranged at an interval of 180°. A magnetic tape 13 is wound around the outer periphery of the rotary head drum 1 by a pair of tape guides 11 and 12 during recording or playback, and four magnetic heads 2 are wound around the outer periphery of the rotary head drum 1 during recording or playback of baseband signals.・4, 6, and 8 are now used.

FIG. 4 shows a track pattern when recording and reproducing baseband signals. Here, the tracks on which recording is performed by each of the magnetic heads 2 to 9 are referred to as A-H, respectively. That is, during one rotation of the rotary head drum 1, the magnetic heads 2 and 4 record one head on tracks A to C, while the magnetic heads 6 and 8 record data on tracks E to G.
．． It is designed to be recorded by one head.

FIG. 5 shows the structure of one field of tracks. One field of the baseband signal is divided into channel I and channel H as a TCI signal (a signal in which a luminance signal and a color difference signal are time-division multiplexed to narrow the band of the baseband signal). Recorded in parallel by rotation. Trunks A and E mentioned above constitute channel I, trucks C and G constitute channel II, and each truck A and each truck C have 243.
A signal of 75H (H is one horizontal period) is recorded, while a signal of 37.5H is recorded in each track E and each track G.

Here, within each track E and each track G, there is a vertical retrace period ■, as indicated by hatching in FIG. 6 for convenience. The vertical blanking period of an HDTV (high-definition) baseband signal is 45H, and the vertical blanking period per channel of a TCI signal obtained by converting this into two channels is 22H and 23H, respectively.

FIG. 7 shows the TCI signal for lH. TCI
Of the signals IH (two pairs of 1800T CI clocks, the TCI clock is written as TCK, and when the number of clocks of the TCI clock is a problem, it is written as ck after the clock number), horizontal synchronization signal 14, burst signal 15
The number of clocks excluding the clocks is 1688ck. In other words, the effective number of samples for luminance signal Y and color signal C is 1 each.
260ck and 420ck, and Y and C for signal processing.
A blank period of 8 ck is provided in between.

By the way, since the aforementioned vertical blanking period for one field is 22H for the shorter channel, the effective number of clocks in the vertical blanking period for one field per channel is 22 x 16BB = 37136ck/channel. .

On the other hand, the number of data of the audio PCM signal is 48 KHz sampling, ■ 6 bits, and is recorded separately into 2 channels ■ and H by superimposing it on the TCI signal of each channel I and ■ using an audio PCM signal superimposing means (not shown). shall be.

FIG. 8 shows a memory map of one field's worth of audio PCM signals. One field of audio PCM signal is divided into two channels, L channel and R channel, for example,
Each block is composed of 67 blocks. By providing an inner code and an outer code as error correction codes,
In order to enable error correction for one field of data up to double error correction and to strengthen the correction capability, Reed-Solomon codes are generated twice. When superimposed on the TCI signal, the L channel audio PCM signal is superimposed, for example, on the vertical blanking interval ■ (see Figure 4) in track E of channel I, and the R channel audio PCM signal is superimposed on track G of channel ■. is superimposed on the vertical retrace period V of .

The block structure of the actual PCM signal is as shown in FIG. 9(a). At the beginning of 24 symbols of PCM data C corresponding to one column in the vertical direction in FIG. Add a 1-symbol block address check code for error checking of address a,
PCM data C is followed by the inner code d and outer code e each consisting of four symbols, and each block consists of 34 symbols (one symbol is 8 bits).

Therefore, the redundancy is about 30%, and 1 in the l field.
The total number of bits of the audio PCM signal in the channel is 3
4 (symbols) x 67 (blocks) x 8 (bits/symbols) = 18224 (bits/channel).

By the way, like the video signal, the audio PCM signal is
(Frequency Modulation) When recording with modulation, the following problems occur. That is,
While the audio PCM signal uses sample value transmission, the video system uses analog value transmission, so the cutoff characteristic of the low-pass filter included in the signal processing circuit is not the roll-off characteristic for sample value transmission. From this, 1. of the PCM signal. The aperture ratio of the eye pattern required for O detection decreases, and distortion of the analog processing circuit (especially the reproduction system) causes waveform distortion between sample values, which also causes the eye pattern to deteriorate. .

Therefore, the inventor devised a digital modulation method that allows PCM signal detection even under the influence of such waveform distortion and waveform interference, and adopted it in this embodiment. As shown in FIG. 10, this digital modulation method converts 2 bits of the PCM signal into four patterns 1 to 2, and allocates the 2 bits to 3 clocks of the TCI clock. That is, in the first of the three clocks, the reference value consisting of 8 bits, for example, 80□°
" is given, and at the second and third clocks, 8-bit data "FF," or "001("
is given. The above 8 bits are set according to the number of bits of the video signal, and the reference value "80." is set to 1/2 of the 8-bit dynamic range, and the "FF
," and "100 HII are the maximum and minimum values within the dynamic range. Note that the above pattern modulation is performed by a modulator 56 (see FIG. 13), which will be described later.

As mentioned above, by allocating 2 bits of the PCM signal to 3 clocks of the TCI signal clock, the total number of recording bits per block is expanded by 1.5 times, to 272
X1.5=408 (bits/block). or,
The audio PCM signal is superimposed on the TCI signal per IH, for example, every four blocks, as shown in FIG. 9(b).

As shown in the figure, a negative horizontal synchronizing signal 16 and a burst signal 17 are added to the beginning of the four blocks of audio PCM signals.

Under the above conditions, the number of PCM clocks per IH is 4
08 (clock/block) x 4 (block/H)
= 1632 (clock/H), and the number of H per channel required to superimpose the PCM signal is (182
24X 1, 5) /1632= 16, 5
It becomes H. Since this 16.5H is smaller than the above-mentioned vertical blanking period 22H per channel, the audio PCM signal can be inserted within the vertical blanking period.

FIG. 13(a) shows a block diagram of the recording system of this high-definition VTR.

Of the video input signals consisting of the luminance signal Y and the chroma signal PR'PR, the luminance signal Y is used as a genlock signal for the system synchronization board 50, and various clocks and synchronization signals genlocked to the input signal from the system synchronization board 50 are required. is output to.

The luminance signal Y and chroma signal PR-PR are sampled at a predetermined sampling frequency by the A/D converter 51, and the luminance signal Y is directly input to the TCI encoder 53, while the chroma signal PR'P11 is input to the chroma vertical filter 52. After vertical filtering is performed in advance, the signal is input to the TCI encoder 53. and,
The TCI encoder 53 performs line sequential processing, expansion processing, compression processing, etc. After that, channel ■ and channel ■
adder 5 as a two-channel TCI signal.
Output on 8.58.

On the other hand, the audio signals of the two channels L and H are sampled by the A/D converter 54 and made into audio PCM signals, and the above-mentioned inner code d and outer code e (Fig. 9(a) )), and then manually inputted to a modulator 56 as a modulation circuit.

Further, a block address a is supplied to the modulator 56 from a block address adding circuit 57, and added to the audio PCM signal. After the modulator 56 performs pattern modulation on the audio PCM signal as shown in FIG.
The signal is supplied to adders 58 and 58 as M signal superimposing means.

The adders 58 and 58 receive the T output from the TCI encoder 53 only during the period corresponding to the vertical retrace period indicated by the adder enable signal supplied from the system synchronous board 50.
The CI signal and the audio PCM signal of the pattern modulator output from the modulator 56 are added and output, and the TCI signal from the TCI encoder 53 is output as is during periods other than the vertical retrace period. . Note that during the vertical retrace period, the Tlj signal from the TCI encoder 53 is set to "OOu" except during the horizontal synchronization period.

After the adders 58 and 58 superimpose the audio PCM signal of the pattern modulator on the vertical retrace period of the TCI signal, the TCI signal is converted into an analog signal by the D/A converter 6o, as in the conventional case, and then the FM modulator converts the TCI signal to an analog signal. After FM modulation by 61,
For example, data is recorded on the magnetic tape 13 by four magnetic heads 63 (for example, magnetic heads 2, 4, 6, and 8 in FIG. 3) via four recording amplifiers 62.

FIG. 13(b) and FIG. 1 show block diagrams of the playback system of the present high-definition VTR.

Signals reproduced from the magnetic tape 13 by, for example, four magnetic heads 63 are amplified by each head amplifier 64,
After each equalizer 65 restores the balance of the signal strength of both sideband waves, the signal is demodulated by the FM demodulator 18 and becomes a reproduced TCI signal.

This TCI signal is used as a time axis error correction means to remove time axis fluctuations.
C.

director) 20 people.

Here, the TCI signal is transmitted by the A/D converter 21.
Converted to 8-bit digital signal and sent to line memory 2
2. At this time, the audio PCM signal superimposed on the TCI signal is also converted into an 8-bit digital signal. At this time, the reference phase of the TCI signal is detected by a detection circuit (not shown) using the burst signal 15 in the TCI signal (FIG. 7), and the reference phase of the TCI signal is detected using the detected signal to By resetting the write clock generator 24 that supplies the write clock Wck to the memory control circuit 23 for each IH, the TCI signal is always sampled and stored with the correct phase. Therefore, the time axis error is absorbed at the time of sampling. In addition, audio P
Since the superimposition phase within the IH is also determined for the CM signal,
The audio PCM signal is also detected at the time it is sampled by the A/D converter 21 of the TBC 20.

The line memory 22 and the line memory control circuit 23 are supplied with the read clock Rck from the read clock generator H25, and the TCI signals stored in the line memory 22 are sequentially read out to the video signal processing section 26 and the audio signal processing section 27. It is now sent to Note that the read clock generator 25 is supplied with TCK from a system synchronization board (not shown), and the line memory control circuit 23 is supplied with TCI to the line memory 22.
When writing and reading signals, the line memory 22
The line address can be specified.

The TCI signal read out from the line memory 22 is input to the TCI signal decoder 28 of the video signal processing section 26, where the TCI signal is converted into a high-definition video signal and sent to a luminance signal via the D/A converter 30. Y and chroma signal PR'P11 are output.

Further, the TCI signal read from the line memory 22 is sent to the PCM gate circuit 31 of the audio signal processing section 27.

This PCM gate circuit 31 is opened in the PCM region within the vertical retrace period of the TCI signal based on the PCM gate signal supplied from the system synchronous board.

The audio PCM signal (first
0) is demodulated by a regenerative PCM detection circuit 32 as a demodulation circuit in claim 3, and an error correction circuit 33 performs error correction as necessary.

Moreover, if it is impossible to correct the error of the error correction circuit 33,
The uncorrectable signal is sent to the interpolation circuit 34, where the uncorrectable data is interpolated based on previous and subsequent data, etc., and then outputted separately into an L channel and an R channel.

FIG. 14 shows a detailed configuration of the modulator 56 in the reproduction system.

This modulator 56 receives 8 signals from the error code generating circuit 55.
A parallel/serial conversion circuit 121 that serially converts a bit-parallel audio PCM signal, and a serial/parallel conversion circuit 12 that converts the serial signal from the parallel/serial conversion circuit 121 into a 2-bit parallel signal.
2, a latch circuit 123 that latches and synchronizes the output of the serial/parallel conversion circuit 122, and a latch circuit 12.
2-bit parallel signal from 3 and 1/3 counter 12
A modulation ROM 125 that performs the modulation shown in FIG. (2) Three-state buffer circuits 127 and 128 that divide the audio PCM signal of the modulator into two channels based on each enable signal.

To describe the operation of the main part of the modulator 56, the 8-bit parallel (1
The audio PCM signal (Fig. 15(b)) of the symbol) is TC
Parallel loading is performed by a K/12 load pulse (FIG. 15(d)). The loaded 8-bit signal is (8/
12) MS at the timing of TCK ((C) in the same figure)
B (Most 51gn1ficant Bit),
As shown in B6, B5, . . . ((e) in the same figure), the signals are serially output one bit at a time and manually input to the serial/parallel conversion circuit 122.

The 2-bit signal converted into parallel data bit by 2 bits by the serial/parallel conversion circuit 122 is converted to T by the latch circuit 123.
It is latched and synchronized by the CK/3 latch pulse ((f) in the same figure), and (MSB, B6), (B5, B) in (g) in the same figure.
4) Each two bits are outputted to the modulation ROM 125 as shown in FIG.

On the other hand, the 1/3 counter 124 is TCK ((a) in the same figure)
The count of "'0 Pa II +""2"" is repeated every l clock, and this is given to the modulation ROMI 25 as the lower address. By the way, the modulation ROM
Since the mapping is set as shown in Figure 16,
One of four patterns corresponding to 2 bits of the audio PCM signal is output every 3 clocks of TCK. For example, if any two bits of the audio PCM signal are (0, O), the variable ROM 125 will generate "'80." for each TCK.

→ "'00H" → "00H"
) is output as shown below.

Since a time delay occurs due to reading in the modulation ROM 125, synchronization is achieved by latching in the latch circuit 126 ((j) in the same figure). In addition, Fig. 15 (i) (j)
In FIG. 16, white circles indicate reference bits, and black circles indicate data bits.

FIG. 2 shows the PCM gate 31 and the first gate in the reproduction system.
A more detailed block diagram of a regenerative PCM detection circuit 32 as a demodulation circuit that demodulates the four patterns shown in FIG. 0 into two bits is shown.

The PCM gate circuit 3■ is a first and second three-state buffer circuit 3 to which the TC■ signals of channel I and channel ■ are respectively supplied from the line memory 22.
5.36, each three-state buffer circuit 3
The gate signals of PCM channel I and channel ■ are supplied from the system synchronous board to the output enable terminal OE of
The M signal region is extracted.

First and second three-state buffer circuits 35.
The PCM signal that has passed through 36 is latched and synchronized by a first stage latch circuit 37. Subsequently, the latch circuit 37
The signal latched by the latch circuit 38 and the latch circuit 4
0 sequentially and are sequentially latched based on the clock ck from the system synchronous board.

The outputs P - P' of the latch circuits 38 and 40 are sent to subtraction circuits 41 and 42, respectively. Latch circuits 38 and 4
The outputs of 0 each consist of 8-bit data, and the 10th
As shown in the figure, “FF.

It has a value of either "80." or "00H". In addition, the subtraction circuits 41 and 42 receive an 8-bit detection reference value Q (Q-"'80.'") from a reference value generation circuit (not shown).
is supplied, and the detection reference value Q is subtracted from the outputs of the latch circuits 38 and 40 in subtraction circuits 41 and 42.

Then, from the subtraction circuits 41 and 42, a combination determination circuit 43
The sign bit (carry bit) of the subtraction result and the absolute value IP-QI IP'Q1 of the subtraction result are sent to the combination judgment circuit 43, which divides the four patterns shown in FIG. It is demodulated into a bit PCM signal.

For example, if the outputs P-P' of the latch circuits 38 and 40 at a certain time are both "FF" and "FF", FIG.
), and at this time, as shown in the figure (b), the sign bits from the subtraction circuits 41 and 42 both become "+", so as shown in the figure (c), (1, 1).

Further, the output P of the latch circuit 38 at a certain time is “FF
,", and the output P" of the latch circuit 40 is "oo,", it corresponds to pattern (2), the sign bit from the subtraction circuit 41 is "+", and the sign bit from the subtraction circuit 42 is "-". Therefore, it is demodulated as (1°0).

Similarly, the output P of the latch circuits 38 and 40 at a certain time
If -P' are both "'0ON", it corresponds to pattern ■, so it is demodulated as (0, O), while the output P of the latch circuit 38 at a certain time is ° "oo, '", When the output P'' of the latch circuit 40 is "FF," it corresponds to pattern (2) and is demodulated as (0, l).

Note that the white circles in FIG. 11(a) indicate reference bits, and the black circles indicate data bits. Further, subtraction in the subtraction circuits 41 and 42 and demodulation in the combination determination circuit 43 based on the subtraction are performed every three clocks of TCK supplied from the system synchronous board.

The 2-bit PCM signal demodulated by the combination determination circuit 43 is sent to the symbolization circuit 44, where it is converted into a parallel signal in units of 8 bits (1 symbol) obtained by demodulation four times, and is sent to the latch circuit 45. The signal is then sent to the error correction circuit 33 in FIG. Note that the latch circuit 45 receives a symbol clock (TCK) supplied from the system synchronous board.
(generated at 12 times the time interval).

Next, a modified example of the demodulation procedure in the regenerative PCM detection circuit 32 will be shown.

In the above embodiment, the outputs P-P of the latch circuits 38 and 40
' is compared with the reference value Q for detection in the subtraction circuits 41 and 42 to demodulate the PCM signal, but the latch circuit 37
- PCM signals can also be demodulated by sequentially comparing the outputs of 38 and the outputs of latch circuits 37 and 40.

That is, the output of the latch circuit 37 changes as shown in FIG. 12(a), the output of the latch circuit 38 changes as shown in FIG. It is assumed that the output is further delayed by one clock from the latch circuit 38 and changes as shown in FIG.

In that case, for example, assuming that the data launched in the latch circuit 37 during the period of the first to third clocks ck and ~ck+ in TCK is in the pattern (2) shown in FIG. 10, the latch circuit When the first 8-bit data "'FF" (FIG. 3(a)) is latched in the latch circuit 37, the reference data "801 (
(0 in the same figure)) is latched, and when the latch circuit 37 latches the second 8-bit data "FF" ((a) in the same figure) based on the clock Ck3 one clock later, the latch circuit 40 The reference data ""80M ((C) in the same figure) is latched.

Therefore, the output of the latch circuit 38 is subtracted from the output of the latch circuit 37 based on the clock ck, and the output of the latch circuit 40 is subtracted from the output of the latch circuit 37 based on the next clock Ck. (Same figure (d)
)), it is possible to demodulate the data of pattern (2) into a 2-bit PCM signal (1, 1) as shown in (e) of the figure.

Further, for example, if the data latched by the latch circuit 37 during the period of clocks ck to ck6 in TCK is pattern 3, the data latched by the latch circuit 37 based on the clock cks is
((a) in the same figure) to the latch circuit 38 ((b) in the same figure)
), and the output of the latch circuit 40 ((C) in the same figure) is calculated from the output of the latch circuit 37 based on the clock Ck6.
), and the combination of subtraction results is +, - (same figure (d)
)), it is demodulated as (1, 0). below,
The data of pattern (2) and pattern (2) are similarly demodulated.

〔Effect of the invention〕

As described above, the magnetic recording and reproducing apparatus according to the present invention basically performs PCM processing on an audio signal during recording, and performs PCM processing on the audio signal during recording.
This configuration includes an audio PCM signal superimposing means for superimposing a CM signal on the vertical retrace period of the TCI signal of each channel.

As a result, the audio PCM signal is superimposed on the vertical retrace period of the TCI signal, so the modulator, demodulator, and head peripheral circuits originally provided for processing the video signal (
A recording amplifier, an equalizer), etc. can be used in common for processing the audio PCM signal, thereby simplifying the configuration and reducing the number of parts. Furthermore, by superimposing the audio PCM signal on the vertical retrace period of the TCI signal, the area of the magnetic tape required for signal recording can be reduced, and as a result, the storage capacity can be increased.

In addition to the above configuration, if a time axis error correction means for correcting the time axis error of the reproduced TCI signal is provided, when the reproduced TCI signal is sampled by the A/D converter of the time axis error correction device, the reproduced TCI signal When the signal is detected, the regeneration T
This means that the audio PCM signal superimposed on the CI signal is also detected at the same time. Therefore, there is no need to separately provide a pulse detection circuit and a reproduction clock generator exclusively for the audio PCM signal, so the number of parts can be reduced.

Furthermore, in addition to the above configuration, a modulation circuit is provided in the audio PCM signal superimposition means, and 2 bits of the audio PCM signal are converted to T (3 of l clocks) before superimposing the audio PCM signal on the TC1 signal
Audio PC that is modulated into four patterns represented by a clock and modulated into the above four patterns by a demodulation circuit during playback.
By demodulating the M signal, similar to the video signal in the TCI signal, the effects of waveform distortion and waveform interference that are likely to occur when the audio PCM signal is directly FM modulated and recorded are alleviated, and the audio PCM signal is reproduced during playback. This enables proper wave detection.

[Brief explanation of drawings]

1 to 12 show one embodiment of the present invention. FIG. 1 is a block diagram showing part of a reproduction system of a high-definition VTR. FIG. 2 is a block diagram showing the detailed configuration of the regenerative PCM detection circuit. FIG. 3 is an explanatory diagram showing the arrangement of magnetic heads on a rotating drum. FIG. 4 is a schematic front view showing the arrangement of tracks on the magnetic tape. FIG. 5 is an explanatory diagram showing the format of the video signal. FIG. 6 is an explanatory diagram showing a part of FIG. 5 in detail. FIG. 7 is an explanatory diagram showing the TCI signal waveform. FIG. 8 is a memory map of the audio PCM signal and error correction code. FIG. 9(a) is an explanatory diagram showing the structure of a block of an audio PCM signal. (in the figure) is an explanatory diagram showing a superimposed waveform of an audio PCM signal on a TCI signal. FIG. 1O is an explanatory diagram showing a pattern modulation waveform of an audio PCM signal. FIG. 11 is an explanatory diagram showing an example of a pattern demodulation procedure in the regenerative PCM detection circuit. FIG. 12 is an explanatory diagram showing another example of the pattern demodulation procedure in the regenerative PCM detection circuit. FIG. 13(a) is a block diagram showing the recording system of a high-definition VTR. FIG. 2B is a block diagram showing a reproduction system of a high-definition VTR. FIG. 14 is a block diagram showing details of the modulation circuit and channel division section in the recording system. FIG. 15 is a time chart showing the operating procedure of each part of the modulation circuit. FIG. 16 is an explanatory diagram showing mapping in the modulation ROM. FIG. 17 and FIG. 18 show a conventional example. FIG. 17 is a schematic front view showing the arrangement of tracks on the magnetic tape. FIG. 18(a) is a block diagram showing a recording system of a high-definition VTR. FIG. 4B is an explanatory diagram showing the reproduction system. 2 to 9 (63) are magnetic heads (rotary heads), 20 are TBCs (time axis error correction means), 32 are reproduction PCM detection circuits (demodulation circuits), 56 are modulators (modulation circuits), and 58 are adders ( (audio PCM signal superimposition means).

Claims (1)

[Claims] 1. After converting a high-definition video signal into a two-channel TCI signal, it is recorded on a magnetic tape using a helical recording method using a rotating head, while the TCI signal reproduced from the magnetic tape by the rotating head is A magnetic recording/reproducing device configured to decode and output the audio signal is provided with audio PCM signal superimposing means for performing PCM processing on the audio signal during recording and superimposing the audio PCM signal on the vertical retrace period of the TCI signal of each channel. A magnetic recording/reproducing device characterized by: 2. The magnetic recording/reproducing device has a built-in A/D converter, and detects the reproduced TCI signal based on the detection of the reproduced TCI signal.
Claim 1, further comprising a time axis error correction means for correcting a time axis error of the reproduced TCI signal on which the audio PCM signal is superimposed by sampling the signal with the A/D converter. The magnetic recording and reproducing device described above. 3. The audio PCM signal superimposition means T of the audio PCM signal.
TC the 2 bits of the audio PCM signal before superimposing it on the CI signal.
Claim 1, further comprising a modulation circuit that modulates into four patterns represented by three I clocks, and a demodulation circuit that demodulates the audio PCM signal modulated into the four patterns during reproduction. The magnetic recording and reproducing device described in 2.