JPS62170015A - Rotary head type reproducing device - Google Patents

Abstract

PURPOSE:To attain excellent tracking even at the time of high speed reproduction by separating a tracking control pilot signal from a reproducing signal and controlling the head displacement in response to the reproducing speed in a rotary head type reproducing device recording a PCM signal. CONSTITUTION:An amplifier 39 outputs an ATF error signal corresponding to the crosstalk of a pilot signal different in frequency for automatic track from an ATF control circuit 36 by a signal being at H when each of rotary heads 1A, 1B traces a PCM area from a terminal 50 at high speed reproduction. The error output and a ramp voltage corresponding to a reproducing speed outputted from a ramp voltage generator 44 in response to the setting speed of a speed setting device 42 are added and the displacement of the heads 1A, 1B is controlled via bimorphs 56A, 56B respectively. Then the heads 1A, 1B are on the track, excellent tracking is applied even at the time of high speed reproduction to surely reproduce the PCM signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application The present invention relates to a rotary head type reproducing device for recording PCM signals on a magnetic tape.

[Summary of the invention]

In a rotary head type playback device that records PCM signals on a magnetic tape, the present invention performs tracking control while the throat traces the PCM signal recording area as it rotates during high-speed playback. , recording date, etc. can be detected.

C. Prior Art] In a VTR (8 mm VTR) that uses a small tape cassette with a magnetic tape width of 8 mm, an audio recording method is used in which an audio signal modulated from F to f is recorded on an inclined track along with a recorded video signal. This is a standard system, and as an option, a PCM area is provided at the end of the track in which the audio signal is digitized and recorded. In other words, the magnetic tape lies within an angular range of 221 degrees with respect to the circumferential surface of the drum.
Tracks with a length of 221 degrees are alternately formed on the tape by two rotating heads. In this track, an audio signal related to one field of the video signal is converted into PCM and recorded in a time-compressed state in an angular range of about 36 degrees from the point when the rotating head starts scanning. be done. subsequent 18
The area corresponding to the angular range of 0 degrees has the color Is of l feel 1 minute.
An image signal and an FM modulated audio signal are recorded.

The remaining 5 degrees is used as a margin period when the He/7 Do is separated from the tape.

Furthermore, for 8 mm VTRs, a multi-PCM format for recording only PCM signals has been standardized. In the case of multi-PCM, the 221 degree winding is divided into 6 sections of 36 degrees each, with a 216 degree section excluding the 5 degree section at the end. A time-compressed PCM signal is recorded on each of these six divided track chains.

By the way, in addition to the recording area for digital audio signals, the PCM area of an 8mm VTR has an ID word recording area where occasional data such as time codes can be recorded. 1 minute PC ~ 1
The δq region contains 69-ts from IDO to TD5,
As shown in FIG. 11, D words IDO to TD5 are recorded in a distributed manner in the PCM δn area of the magnetic tape. Among these TD words TDO to ID5, 10(l is used as a mote code to define the mode of the word.

[Problems to be solved by invention C] - In conventional VTRs, when performing high-speed playback such as during high-speed search, the rotation throat does not move as shown by the broken line arrow in Figure 11? M
number of tracks (T, l, Tn,,,T,,,2...
). For this reason, all six rD words ■DO to ID5 recorded in each of the PCS1 areas cannot be pink-amplified.

That is, as shown in FIG.
In the CM area, the TD words TDO and ID3 are picked up, and in the PCM S'N area of another track Tn, the ID words TD1 and ID4 are pinocqua-knobbed. T in ID word T D 1- T D 5
DO is used as a mode code to define the mode of the word. ID used as this mode code
If the word IDO cannot be big-amplified, even if other ID words can be big-amplified, the meaning cannot be interpreted.

If ID words of different modes are recorded in the frame for each track, if the ID word rDO cannot be picked up, the mode cannot be set, and there is a risk that other big-amplified ID words may be interpreted with different meanings. be.

Therefore, it is an object of the present invention to
An object of the present invention is to provide a rotary gutter type playback device capable of playing back words.

Means for Solving the Problem] This invention provides tracking for each PCM area formed by dividing one track into a plurality of parts. In a rotary head type reproducing device designed to record a third-party barrosoto signal and a digital signal, a circuit for separating a pilot signal from a repeating signal and a circuit for detecting a tracking deviation in the separated pilot signal are used. a control circuit, a head displacement means for displacing the head based on the output of the control circuit, a signal generation circuit for giving an adaptive control signal to the head displacement means according to the reproduction speed ζ2, and a magnetic A signal generation circuit that outputs No. 1z corresponding to the predetermined PCM area of the tape, and a variable speed cab system? This is a rotary head type reproducing device equipped with 111 circuits.

[Effect]

When the reproduction speed is set by the speed setting circuit 42, the frequency ratio of the l/n round branch circuit 43 is controlled, the rotational speed of the xepstan motor 45 is set, and the output voltage from the lamp voltage generation circuit 44 is set. A lamp voltage corresponding to the speed is generated.

The ATF error signal for the period corresponding to the playback PC~D area and this lamp voltage are added in an adder circuit 51, and this QO
m3: The output of the circuit 51 drives the 7r1c, fmorphs 56A and 56B.

From this point, when high-speed reproduction is performed, the rotary heads IA and IB trace along the reproduction PCλ·1 area.

Therefore, rD word ■DO~ID5 of PCM area
You can play all of the following:

Embodiment] Drawings of an embodiment of this invention are shown in the following order. ,,! ? I will explain.

a. 8 mm VTR head and tape system and track pattern b. 8 mm VTR (7) PCM7'-event configuration c. A-F tracking d. Configuration of an embodiment and its operation a. 8 mm VTR Head, tape system, and track pattern FIG. 1 shows an embodiment of the present invention.

In this embodiment, an 8 mm VTR is used to reproduce a multi-PCM signal in which only the PC■ signal is recorded on a magnetic tape.

In FIG. 1, IA and IB are rotating heads. The rotary nozzles IA and IB are mounted on the drum 2 with an angular spacing of 180 degrees, as shown in FIG.

The extending directions of the air gaps of the rotating heads IA and IB are different, and the structure is such that crosstalk from adjacent troughs can be suppressed by azimuth loss.

Four 8 mm wide magnetic tapes 3 are wound diagonally around the circumferential surface of the drum 2, 7'1. drive at a constant speed.

The winding angle of the magnetic tape 3 is 221 degrees.

In the case of multi-PCM, as shown in FIG. 3, a 221-degree winding is divided into six sections of 36 degrees each, with a 216-degree section excluding the 5-degree section at the end. These six sections are divided into channels 1, 2, and 30 according to the Inα order in the scanning direction of the head. Channel 2. . . . is called channel 6. In the case of multi-PCM, the tiger, Kuformanoto, is the fourth
It is standardized as shown in the figure. In the 4th M, 1
In these sections, the rotary head LA or IB connects the magnetic tape 3.
From the right side, where it starts to come into contact with the head, first, the tip part has a plunge part 11 that corresponds to 5 degrees of the rotation angle of the head, and the second half of this plunge part 11, which is 2.06 degrees (38 degrees (H is the horizontal period) of the video signal, ↑
The period of interest is the preamble 12 for the subsequent PLL input. Following this preamble 12, a PCM data recording area 13 is provided over 26.32 degrees. The period < 2.06 degrees (3H) following this PCM data recording area 13 is considered as postamble 14, which is a pack margin against recording position deviation during after-recording, and the subsequent 2.62H is used for each PCM data recording area 13.
It is used as a guard section 15 between other sections of the CM area.

b. PCM data structure of 8 mm VTR FIG. 5 shows the data structure of the PCM data to be recorded. One word is 8 bits, which is the sampling wave number 2 + h, the peak angle 5 horizontal frequency 'l, 10 bits,
This is an audio signal that has been digitized in 8 bits and converted into 8 bits by 10-8 conversion (non-linear quantization). The data for the first half and yield is divided into 132 blocks. The digital audio signal for one field in the TSC system is 1050 words. On the other hand, if one unit of data is composed of 8 words and 132 blocks, it will be 1056 words. Therefore, six ID words are added.

The 1056 words, including the ID word ID O-T D 5, are spaced horizontally by 44 pro7 every two words. If the TD word is punctured, two words (CL+, R+), apart from parity data, are arranged horizontally. This one field worth of digital audio signal and I
Two parities are added to the D word. One column of the audio system in each row of the above matrix configuration is written as W9. W
, . . . W, the first parity sequence P is formed from 8 words belonging to each data sequence separated by a horizontal distance of 14 or 15 blocks.

Further, a second parity sequence Q is formed from nine words extracted from each of the nine audio sequences W0 to W and the parity sequence P at a distance of 12 blocks. The distance between these two parity sequences is in units of two or three blocks. and,
The first parity series P is placed in the center of the block,
The second parity series Q is arranged at the end within one block.

As shown in Fig. 6, each of the 132 blocks includes an 8-word digital audio signal, an ID query, and 2 words of validity and data, and a 16-bit CRC code is added to each block. ,Also,
A block period signal and a block address signal are added. Then, these data are time-compressed, and the biphase mark change m (the data of r 1 j is, for example, 5.8M
Hz, 'OJ data is modulated into, for example, a 2.9 M)lz signal) and recorded on a magnetic tape.

The six TD words IDO to ID5 mentioned above are used for recording various information. Specific ways to use the ID word include recording a time code, recording a program number, and recording the date and time of recording. As shown in Figure 7, these ID words I
Among DONID5, IDO is used as a mode code. This mode code rDO sets the mode of data recorded in ID1 to ID4.

Examples of modes set by ID mode IDO include those shown in 8th UAA-8I171F. When the TD mode IDO is (10000000), for example, as shown in FIG. 8, a frame number is recorded for each of ID1 to ID4s for a time of 1 minute and 2 seconds. +D
When the mode IDO is, for example, (01000000), as shown in FIG. 8, program numbers 7, 71-numbers, and minute 1 second from the start of each force/throat are recorded in ID1 to ID4, respectively. For example, ID mode TDO is (
11000000), as shown in Figure 8C,
One week of January 5, 2018 at the time of recording is recorded in ID1 to ID4, respectively. For example, ID mode TDO is (0010000
0), as shown in the eighth diagram, the recording time of 1 minute and 1 second and the frame number are recorded in ID1 to ID4, respectively. For example, if iD mote rDO is (101000
00), the time of 1 minute and 9 seconds from the beginning of the program is recorded in ID1 to ID4, respectively, as shown in FIG.

For example, when the ID mode IDO is (01100000), the program number indicating the beginning position of each program and the time 1 minute 9 seconds are rDO, as shown in Figure 8F.
~rD4 respectively.

In ID mode, ID5 has each of its 8 bits 1-
BO to B7 have the following information. As shown in Figure 7,
BO indicates whether this ID word is valid, Bl, B
2 indicates the type of digital audio signal (mono, stereo, bilingual, etc.), B3 distinguishes between audio information or other information for one channel, and B4 makes a similar distinction for the other channel. Yes, B5. B6 is a bit that is set high at the start and end of recording, and B7 is a bit for preventing dubbing.

c.ATF tracking 8mm VTR uses AT as a trunking servo.
F method is used. In the ATF system, four pilot signals f1 to f are used, and these four pilot signals f and f4 are cyclically recorded for each track. During playback, the pyro
Tracking servo is applied so that the amount of crosstalk is constant based on the level of the throat signal. For example, frequency f2
When reproducing a rack (in which a viroft signal of 2 is recorded), pilot signals on both sides (tuna and fff) are detected, and the signal level of the difference between the pilot signal of frequency r2 and the adjacent pilot signal is detected.

Between the playback track and one adjacent track, (ft-
ft) difference frequency, for example 4. The level of the component of IKII2 is detected, and the level of the component of the difference frequency (f2-f, ), for example, 16 kHz, is detected between the reproduced track and the other adjacent track. Shock tracking control is performed so that the levels of these difference signals are equal. The frequency of this 4 (Prisoner's Pyroso t signal is ((z − r,
) and (f□-f4) become 16KHz, and (f, -
If f2) and (fJ-f,) are selected in a relationship of 45Kllz, then for all tracks, the frequency of the adjacent Byronoto signal is 45K)Iz, 16K.
)Iz.

d.-Configuration and operation of the embodiment In FIG.
1B respectively. The playback amplifiers 21A and 21B are supplied with the PCM area signal corresponding to the designated channel from the terminals 22APi and 22B, and the playback amplifier 21
The playback outputs of the designated channels from A and 21B are taken out alternately. The pulse generation circuit 23 generates a PCM area signal whose phase amount is controlled in six stages by the output of the channel setting circuit 20, and the channel setting circuit 20 selects channels 1 to 6 of the PCM signal.
When one of the channels is set, the amount of phase shift of the pulse generating circuit 23 is controlled according to that channel.

The output of the reproduction 7 amplifiers 21A and 21B is the PLL24! This signal is also supplied to the demodulation circuit 25. PLL2
4, the bit clock is extracted and the output of the PLL 24 is supplied to the demodulation circuit 25. A demodulation circuit 25 performs demodulation of the phase mark modulation. The PCM signal demodulated by the demodulation circuit 25 is subjected to error detection using a CRC code in the CRC detection circuit 26, and then sent to the error correction circuit 27.
and error correction is performed.

The data that has not been error corrected by the error correction circuit 27 is
The signal is supplied to the 8-10 conversion circuit 28, converted into a 10-bit linear P'CM signal, and sent to the D signal via the interpolation circuit 29.
/A converter 30? Two supplied. D/A coefficient
At 30 pm, the PCMf word is converted into an analog audio signal, and this analog audio signal is supplied to the noise reduction circuit 32 via the low-pass filter 31.Output terminals 33A and 33B are led out from the noise reduction circuit 32, and the output terminals 33A and 33B are output. Analog audio signals of left and right channels are taken out from terminals 33A and 33B, respectively.

Further, the outputs of the regenerative amplifiers 21A and 21B are supplied to a low-pass filter 35, and a regenerated pilot signal is extracted by the low-pass filter 35.

This regenerated pilot signal is passed from the low-pass filter 35 to A
TF system? 111 circuit 36.

On the other hand, in the case of the NTSC system, a reference signal having a frequency of 378 fH (f, 4: horizontal frequency), for example, is supplied to the input terminal 37, and this reference signal is supplied to the l/N frequency dividing circuit 38. The 1/N frequency divider circuit 38 generates the reference bar 1″ lot signal f, ~
The reference pilot signals f, to f4 are switched for each track in synchronization with the RF switching pulse and supplied to the ATF control circuit 36.

The ATF control circuit 36 compares the amount of crosstalk between pilot signals of adjacent tracks on both sides, and generates a TF error signal based on this comparison. This ATF error signal is supplied to the amplifier 39 and also to the +70 arithmetic circuit 41.

42 is a speed setting circuit. When the playback speed is set by the speed setting circuit 42, the 1-coat frequency division ratio is set based on this playback speed.
/n frequency dividing circuit 43; and a lamp voltage based on this reproduction speed is generated from lamp voltage generating circuit 44.

The rotation of the spindle motor 45 is detected by the FG head 46, and the output of this FG head 46 is sent to the PG amplifier 47.1/
The signal is supplied to the speed servo circuit 48 via the n frequency divider circuit 43. The output of the speed servo circuit 48 is supplied to an adder circuit 41, and the output of the adder circuit 41 is co-supplied to the spindle motor 45 via a drive amplifier 49. The rotation of these loop spindle motors 15 is controlled.

The amplifier 39 and the lamp voltage generation circuit 44 have a terminal 50.
A PCM area signal (D in FIG. 9) is supplied from the PCM area signal (D in FIG. 9). This PCM area signal causes the amplifier 39 and the ramp voltage generation circuit 44 to operate for a period corresponding to the PCM area of the reproduction channel.

The output of amplifier 39 is supplied to adder circuit 51 .

In addition, a lamp voltage corresponding to the reproduction speed output from the lamp voltage generating circuit 44 (E in FIG. 9) is supplied to the adder circuit 51, and the ATF error signal (F in FIG. 9) sent through the amplifier 39 and this The lamp voltage (FIG. 9E) is added. The output of the adder circuit 51 is sent to the sample and hold circuits 52A and 5.
2B.

Sample and hold circuits 52A and 52B: As shown in FIGS. 9G and 9H, respectively, sample and hold pulses corresponding to the switching of IA and IB to rotation are supplied from terminals 53A and 53B, respectively. Ru. Addition circuit 5
1 is alternately sampled and held in sample and hold circuits 52A and 52B, and the sample and hold circuit 52
A and 52B outputs are low pass filters 54A and 54
The signals are supplied to drive amplifiers 55A and 55B through the respective terminals B. The outputs of drive amplifiers 55A and 55B are supplied to bimorphs 56A and 56B, respectively, and the outputs of drive amplifiers 55A and 55B drive bimorphs 3[A and 16B, respectively.

FIG. 9 shows signal waveforms at various parts when channel 3 of multi-PCM is reproduced at high speed. The terminal 50 has a ninth
As shown in the figure, the period in which the rotary head IA traces the channel 30PC to 1 area in Figure 9 and the period in which the rotary head IB in Figure 9C traces the PCM of channel 3
A PC~1 area signal is supplied which is at a high level for a period corresponding to the period for tracing the area. Therefore, while the rotary heads IA and IB trace the PCM area of channel 3, as shown in FIG.
1 is supplied with an ATF error signal. Also, at this time, the lamp voltage shown in FIG. 9E is supplied to the addition circuit 4!51.

Then, the output of the adder circuit 51 is as shown in FIG. 9G and FIG. 9F.
The bimorphs 56A and 5 are sampled alternately by the sampling pulses shown in FIG.
6B respectively.

As a result, the bimorphs 56A and 56B are driven for a period corresponding to the PCM area of channel 3 by the drive voltage generated during the period corresponding to the PCM area of channel 3 shown in FIGS. 9-1 and 9-J, respectively. Ru.

Therefore, when channel 3 is played back at high speed, the rotating head will move to channel 3 as shown by the broken line arrow in FIG.
P Scan along the CM area.

2, even during high-speed playback, the ID word ID recorded in the PCM area of channel 3 of
You can pink up all 0-D5.

In this way, even during high-speed playback, TD words lDO to TD5
Since all can be picked up, the bonds fH of the ID words IDQ to ID5 can be read as Furukawa during high-speed playback. The assigned ID word is sent from the error correction circuit 27 to the system controller 60, and various recorded information is displayed on the display section 61.

Effects of the Invention] According to the invention, when high-speed playback is performed, rotation-7-do IA and IB are traced along the PCM area. Therefore, even during high-speed playback, TD word ■DO~TD
You can pick up all 5. in this way,
Since all of the TD words TDO to rD5 can be picked up even during high-speed reproduction, the information of the TD words IDC1 to IDC105 can be utilized during high-speed reproduction.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a route diagram of an 8 mm VTR head and tape system to which this invention can be applied, and Figs. 3 and 4 are track formats of an 8 mm VTR. Route map used for explanation, Figures 5 and 6
The figure is a route map used to explain the data structure of an 8mm VTR, Figures 7 and 8 are route maps used to explain the ID data of an 8mm VTR, and Figure 9 is an explanation of an embodiment of this invention. FIG. 1O is a route diagram used to explain the operation of an embodiment of the present invention, and FIG. 11 is a route diagram used to explain the conventional reproducing apparatus. Explanation of main symbols in the drawings LA, IB: Rotating head, 36: ATF city II
1ff11 circuit, 44: lamp voltage generation circuit, 45
: Cab stan motor, 48-speed servo circuit,
56A, 56B: Highmorph. Helicopter ``ILσ Taped Figure 2 Figure 4 Figure 7 Word Figure 7 Mo V1 Figure 8 A 7-D 2 Figure 8 B Figure 8 C = 1 meet'' 4 8D Figure 10 Washed rice t-shikuni

Claims (1)

[Claims] In a rotating head type playback device that records a pilot signal for tracking control and a digital signal in each PCM area formed by dividing one track into a plurality of areas, the circuit separates the pilot signal from the playback signal. a control circuit for detecting tracking deviation using the separated pilot signal; a head displacement means for displacing the head based on the output of the control circuit; and adaptive control for the head displacement means according to the playback speed. A rotary head type playback device comprising a signal generation circuit for providing a signal, a signal generation circuit for outputting a signal corresponding to a predetermined PCM area of a magnetic tape, and a capstan control circuit capable of changing speed.