JPS62143244A - Setting circuit for program search operation of magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent malfunction in program search due to the disturbance from adjacent to adjacent tracks by outputting an output of a magnetic head for the LP made from a preamplifier at all times during the period when the program search is executed in the PCM multi-mode. CONSTITUTION:Magnetic heads 1a, 1b for the SP mode are pressed onto a magnetic tape 33 and magnetic heads 1c, 1d for the LP mode are pressed onto the tape 33 respectively in the mode recording/reproducing the video signal, and the sound signal subjected to PCM modulation is recorded/reproduced during the overlap period turned by 36 deg. and the video signal is recorded/reproduced during the period of next 180 deg.. Thus, a track T formed on the magnetic tape 33 consists of a section 37 formed during the overlap period and a section 36 formed while the magnetic heads are turned by 180 deg. in succession to the overlap section, a PCM sound signal is recorded on the overlap section 37 and a video signal is recorded on the 180 deg. section 36.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a helical scan type household magnetic field device having a first mode for recording and reproducing video signals and a second mode for recording and reproducing only audio signals. Recording and reproducing device (hereinafter referred to as VTR)
In particular, the present invention relates to a cueing operation setting circuit that enables cueing operation in the second mode.

[Background of the invention]

Recently, a helical scan type home VTR has been developed which has two modes: a mode for recording and reproducing video signals and a mode for recording and reproducing only audio signals. As an example, when recording an audio signal, there is a system that divides the recording track into several areas and records, for example, a PC or W audio signal (hereinafter referred to as a PCM audio signal) in each area. (For example, Japanese Patent Application Laid-Open No. 58-222
Publication No. 402).

On the other hand, as is well known, in devices that record and play back audio signals using conventional fixed heads, it is possible to automatically detect the earlier application of a song and realize the ability to select the song you want to listen to. There is.

Therefore, it is desirable that the system described in Japanese Unexamined Patent Publication No. 58-222402 also be provided with such a cueing function for audio signals.

[Purpose of the invention]

An object of the present invention is to satisfy such a demand, and to be able to accurately locate the beginning of a magnetic tape regardless of whether tracks are formed in SP (standard) or LP (long time) mode. The object of the present invention is to provide a cueing operation setting circuit that is configured to perform a cueing operation.

[Summary of the invention]

In order to achieve this object, the present invention multiplex-records a search signal (hereinafter referred to as ID data) necessary for cueing with a PCM audio signal, and at the same time, during the search period from the start of cueing to the end of cueing, 5 P/LP Automatic discrimination is stopped, and the ID data search is always performed using the output of the LP magnetic head with a narrow trunk width.

[Example of actual invention]

First, a mode in which video signals are recorded and reproduced too much and a mode in which only audio signals are recorded and reproduced in the present invention will be explained.

FIG. 2 is a plan view showing the head cylinder portion of the magnetic recording/reproducing apparatus according to the present invention.

As shown in the figure, there are 9 parts around the head cylinder 32.
Four magnetic heads 1α with angular spacing of 0°.

1d, 1b, and 1c are provided, and a magnetic tape 33 is wound around the outer periphery of the head cylinder 32 over a range of approximately 216 degrees by tape guides 34 and 35. The head cylinder 32 rotates in the direction of arrow A, and the magnetic tape 33 runs in the direction of arrow B, whereby each of the magnetic heads 1α to 1d scans the magnetic tape 33 while rotating about 216 degrees.

Here, since the four 8-air nodules 1α to 1d are arranged as described above, the magnetic heads 1α and IA are in a symmetrical positional relationship with respect to the rotation axis of the head cylinder 32 (this can be referred to as
The same applies to the magnetic heads 1c and 1d (hereinafter referred to as facing each other).

Therefore, while one of the two opposing magnetic heads (for example, magnetic nodes 1α and 1h) rotates by 36° (= 216° - 180°) after it starts contacting the magnetic tape 33, the magnetic head of the other magnetic head The head is also in contact with the magnetic tape 33. That is, the valley magnetic heads 1α to 1d are 121
The i-step 33 is in contact with the tape 33 during a rotation period of 6 degrees, and during the first rotation period of 36 degrees, both of the two opposing magnetic heads are in contact with the magnetic tape 33. This 66
The rotation period of ° is called the overlap period.

The two opposing magnetic heads ioL and 1b run the magnetic tape 33 at a standard speed to perform recording and reproduction.
sp) mode, and the two opposing magnetic heads 1c and 1d are used in a long-time (LP) mode in which the magnetic tape 33 is run at a speed slower than the standard speed to enable long-time recording and playback. used. In addition, in order to enable azimuth recording, the azimuth angles are made different between the two opposing magnetic heads, and in FIG. 2, + is used to distinguish the azimuth angles of the magnetic heads.

A - sign is added.

With this configuration of the head cylinder 32, in the mode of recording and reproducing video signals, the magnetic heads 1a,
1h, and during an overlap period in which the magnetic heads 1c and 1d rotate 66 degrees after contacting the magnetic tape 33 in the LP mode, a PCM-modulated audio signal (hereinafter referred to as PC
M audio signal) is recorded, 8 times are performed, and the next 18 times are recorded.
o.

During the period of rotation, video signals are recorded and reproduced.
□ As a result, as shown in FIG. 5, the track T formed on the magnetic tape 33 is divided into sections (hereinafter referred to as overlap sections) 3 formed in the overlap period.
7 and a section 36 formed during the period in which the magnetic head rotates 180 degrees following the overlap section (hereinafter referred to as the 180 degree section).
The M audio signal is recorded, and the video signal is recorded in the 180° section 36.

Note that this method of recording video signals and audio signals is called an overlap recording method.

Next, in the mode for recording only audio signals, the magnetic head contacts the magnetic tape 33 at 216° in FIG.
The rotation section is divided into six sections of 36 degrees each, and PCM audio signals are recorded and reproduced individually for each section.

As a result, the magnetic tape 33 is divided into six areas in the width direction, as shown in FIG. 4, and a track T is formed for each of these divided areas.

This recording method is called the PCM multi method, and each area is divided into channels (channels) i, cA in the scanning direction of the magnetic head.
2. ..., ch6. Also in this method,
The SP mode and the LP mode can be selected depending on the scanning speed of the magnetic tape 33 and which of the magnetic heads 1a, 1b or the magnetic heads Ic, 1d is used.

FIG. 5 is a schematic diagram showing the structure of the PC3f audio signal, and shows the section recorded and reproduced during the period in which the magnetic heads 1σ to 1d rotate through 36 degrees.

As shown in the figure (α), this section is a preamble before the real data divided into 162 blocks.

Later, a margin section called a boss full is provided, and one block includes a synchronization signal, an address signal, data, and a C for error detection, as shown in FIG. 5(b).
It consists of R(,' C code. Also, Fig. 5(7+
The data in one block shown in ) consists of 10 words as shown in FIG.
(Left) Consists of channel PCM audio data and index data ID used for cueing. Note that several Intex data IDs are inserted in each block (FIG. 5 (bl)).

As described above, video signals and PCM audio signals are recorded on the magnetic tape 33. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a reproduction system of a helical scan type magnetic recording and reproducing apparatus using an embodiment of the cue operation setting circuit according to the present invention, in which 2a to 2d are rotary transformers, 3α to 3d are transistors, 4cL to 4d are capacitors, 5α to 5d are preamplifiers, 6α, 6b, 7α,
7b.

8α, 8b, 9 are switch circuits, 10 is an audio signal input terminal, 1] is an audio signal output terminal, 12 is a PCM processing circuit,
13 is an ID search circuit, 14 is a cue start signal input terminal, 15 is an OR circuit, and 16 is a band pass filter (B
PF ), 17 is a detection circuit, 18 is a comparator, 19 is a frequency divider, 20 is a capstan motor, 21 is a D flip-flop, 22 is an AND gate, 23 is a buffer, 1 is a differentiation circuit, 25 is an inverter, 26 .27 is the power supply terminal,
28 is a head switching pulse input terminal, 29 is a video signal input terminal, 30 is a video signal output terminal, and 31 is a video processing circuit.

In the figure, the magnetic heads 1α and 1b are for the SP mode, as explained in FIG.
c and 1d are for LP mode. The SP and LP modes are set by the output of the AND gate 22. In the case of sp mode, the output of the AND gate 22 is '
H'' (high level), transistors 6α and 3h are turned off, transistors 5c and 5d are turned on, and switch circuits 8α and 8A are closed to the S side.In addition, in the LP mode, transistors 3cL to 6d and the switch The circuits 8α and 8b are in the opposite state to the above.

First, a case will be described in which a video signal and a pcM audio signal are reproduced from a magnetic tape on which they are recorded using the overlap method.

Now, when the SP mode is set, the output of the AND gate 22 turns off the transistors 3a and 54, and turns off the transistor 5.
Since c and 3d are on, the reproduction signals of the magnetic heads 1α and IA are transmitted to the rotary transformers 2α and 2b1 and the capacitor 4cL, respectively.

4h and is amplified by preamplifiers 5α and 5A. The reproduction signal amplified by the preamplifier 5a is sent to a switch circuit 6α,
The reproduction signal supplied to the C side of the switch circuit 6b and amplified by the preamplifier 5b is supplied to the b side of the switch circuits 6α and 6b.

These switch circuits 6α, 6b are switched and controlled by the head switching signal A from the input terminal 28, and the magnetic head 1α
is 180° of the track T (FIG. 3) on the magnetic tape 33.
When in the section 36, the switch circuit I@6α is closed to the C side and the switch circuit 6b is closed to the b side. Conversely, when the magnetic head 1b is in the 180° section 36 of the track T, the switch The circuit 6α is closed to the b side and the switch circuit 6
b closes to C side. As a result, the switch circuit 6α)
are 180 of the track T by the magnetic herad 1α, 1h.
The video signal reproduced from the interval is continuously obtained, and the PCM audio signal reproduced from the overlap interval 37 (FIG. 3) of the track T by the magnetic heads 1α and 1b is intermittently obtained from the switch circuit 6b. .

The video signal obtained by the switch circuit 6α is sent to the switch circuit 8
The signal is supplied to the video processing circuit 31 via α, where it undergoes processing such as demodulation, and a mark-type video signal is obtained at the output terminal 30. In addition, p c obtained by the switch circuit 6b,
The sr audio signal is sent to PC,4 via a switch circuit 8h.
The signal is supplied to the f processing signal 12, where it is subjected to processing such as decoding and time axis expansion, and a continuous audio signal is obtained at the output terminal 1].

In the LP mode, the output of the AND gate 22 turns on transistors 3α and 3b, and turns on transistors 5c and 3b.
3d is off force 1, magnetic head 'Ic, 'Id
The reproduced signals are transmitted through rotary transformers 2c, 2d, and
Passes through capacitors 4c and 4d to preamplifiers 5c and 5d.
is amplified.

The playback signal amplified by the preamplifier 5c is sent to the switch circuit 7.
The playback signal supplied to the C side of α, 7b and amplified by the preamplifier 5d is supplied to the b side of switch circuits 7α, 7A. The switch circuits 7α, 7b perform the same operation as the switch circuits 6α, 6h in response to the head switching signal A from the input terminal path, so that the switch circuit 7α reproduces data from the 180° section 36 (FIG. 3) of the track T. The PCM audio signal reproduced from the overlap section 37 (FIG. 3) of the track T is intermittently obtained from the switch circuit 7b.

The subsequent processing is the same as in the SP mode.

The sp and LP modes are set by reproducing a predetermined signal recorded on the magnetic tape 33 and detecting it.

This is done automatically by making a judgment. This predetermined signal includes:
With the fixed head, it is possible to use a four-frequency pilot signal that is recorded and reproduced mixed with the tracking signal and video signal recorded along the edge of the magnetic tape 33, but here, this reproduced pilot signal The case of using is explained below. SP/LP automatic determination using this pilot signal is EPxe.

Detection circuit 17. Comparator! 81 frequency divider 19.

That is, in the case of the overlap recording method, the switch circuit 9 is closed to the C side, and the video signal that has passed through the switch circuit 8a passes through the switch circuit 9 to the E P F 16.
supplied to This video signal has a four-frequency pilot signal multiplied by X, and the BPF 16 separates this pilot signal. This pilot signal is transmitted to the detection circuit 1
7 and is supplied to the comparator 1B. On the other hand, the capstan motor 20 outputs an FG multiplied signal with a frequency proportional to its rotation speed, and after being divided by the frequency divider 19,
The signal is supplied to a comparator 18 and compared in frequency with the pilot signal from the detection circuit 17.

By this frequency comparison, the recording signal of the magnetic tape 33 is
Comparator 1 receives signals of different levels depending on the P and LP modes.
8 and is supplied to the AND gate 22 as a 5 P/L P switching signal.

The operation in the case of the PCM multi system is almost the same as in the case of the above-mentioned overlap recording system, but the control of the switch circuits 6a, 6h, 7a, and 7b is different.

That is, in the sp mode, when the magnetic head 1α scans the track of a designated channel on the magnetic tape 33 (FIG. 4) in response to the head switching signal A from the input terminal 28, the switch circuit B6b is switched. When the switch circuit 6h is closed to the α side and the magnetic head 1b is reproducing and scanning it, the switch circuit 6h is closed to the b side. The PCM audio signal that is intermittently reproduced from the track of this designated channel is supplied to the PCM processing circuit 12 via the switch circuit 8b. In this case, the switch circuit 6a is controlled at the same time as the PCM audio signal of the other channel, but since this is supplied to the video processing circuit 3 via the switch circuit 8α, it is cut off there, causing no particular problem. do not have.

In the case of LP mode, switch times! 2! The PCM audio signal of the designated channel is obtained from bb and processed in the same way as in the sp mode.

In the case of the PCM multi system, a four-frequency pilot signal is superimposed and recorded on the PCM audio signal, and since the switch circuit 9 is closed to the d side, this pilot signal is used to determine sp/LP. will be carried out.

Next, a cueing operation setting circuit according to the first aspect of the present invention used in such a reproduction system will be explained.

Generally, cueing is performed by running the magnetic tape at high speed, so when considering the response of automatic SP/LP discrimination, its followability deteriorates.

For example, even if the recording pattern on the magnetic tape changes from SP mode to LP mode, the mode will remain SP for a while.
mode remains. Furthermore, as shown in FIG. 6(α), when the tracks of the SP mode pattern are being reproduced using the SP mode heads 1α and IA, the adjacent tracks are close to each other due to the relationship between the track pitch and the track width of the magnetic head. However, when the sp mode head 1α, iA is playing back an LP mode pattern track, as shown in FIG. A playback output that does not include the interference N from the adjacent track is obtained, which increases the possibility of malfunctions occurring in the automatic SP/LP discrimination, and may also cause malfunctions due to the inability to accurately reproduce the LD signal necessary for cueing. Conceivable. For this purpose, SP
If a first music program is recorded in the LP mode and then a second music program is recorded in the LP mode, there is a possibility that the beginning of the second music program cannot be found. On the other hand, the reproduced output waveform S obtained by the LP mode heads 1c and 1d is as shown in FIG. Therefore, the ID signal can be reproduced accurately and erroneous cueing operations can be prevented.
In Figures 6 and 7, A is a head switching signal.

From the above, in this embodiment, during cueing operation,
An LP mode head is used for the LP mode.

In FIG. 1, an ID search circuit 13, an OR circuit 15, and a D flip-flop 21 constitute the main parts of this embodiment, and a differentiation circuit 24 and a buffer 23 constitute the D flip-flop 21.
It constitutes a reset circuit for the flip-flop 21.

The operation of this embodiment will be explained below using the timing chart of FIG. Note that each signal in FIG. 8 is given the reference numeral of the corresponding signal in FIG. 1.

Now, time T. When the power supply voltage VCC is applied from the input terminal 26, a pulse B representing its rising edge is obtained in the differentiating circuit and shaped into a waveform by the buffer 23. The output pulse R5T of this buffer 23 is supplied to the D flip-flop 21 as a reset pulse. When the D flip-flop 21 is reset by this, the i
Output SB' becomes H'', and AND gate 22 is connected to comparator 1.
The SP/LP automatic discrimination signal SLP from 8 is allowed to pass. The level of the output C of the AND gate 22 changes according to the level of the 5P/LP automatic discrimination signal SLP, and the SP or LP mode is set.

Here, input terminal at time T! When the cue start signal S of H'' is supplied from 4 to 4, the ID search circuit 13 starts operating, and the ID
Detect data and make decisions.

Along with this, the cue start signal S is set to OR time J-31.
5, and its output SE is supplied to the D flip-flop 21
It is supplied by inputting T to . At this time, the η output of the D flip-flop 21 is "H', and the η output is also the D input, so at the same time as the cue start signal S is received, the η output SE' of the D flip-flop is inverted. L
” becomes.

For this reason, the output C of the AND gate 22 is SP/LP
Regardless of the automatic discrimination signal, it becomes "L", and the LP mode is fixed, and cueing is performed using the magnetic heads 1c and 'Id.

Thereafter, at time T, the ID search circuit 13 detects the ID data for the designated music program and outputs a cue end signal E of H'', which is supplied to the OR circuit 15, and its output SE is sent to the D flip-flop. At this time, the output S of the D flip-flop 21 is
Since E/ is "L", the υ output of the D flip-flop 21 is inverted SE' and becomes "H" at the same time as the signal SH is supplied.

As a result, the output C of the AND gate 22 is set to level toner, sp or LP mode according to the level of the SP/LP automatic discrimination signal.

In this way, the LP mode is always set during the cueing operation, and the search for predetermined ID data is performed accurately.

FIG. 9 is a block diagram showing another specific example of the reproducing system of the magnetic recording/reproducing apparatus using the above embodiment.
d is rotary transformer, 39α.

39b is a switch circuit, 40α and 40h are capacitors, 41α and 41b are preamplifiers, and 42α and 42b are switch circuits. Portions corresponding to those in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

When the park is opened, the switch circuits 39a and 39b are connected to the L side when the output C of the AND gate 22 is L'', and the arrow 4
3α, 43bO) 9 ports < Magnetic head 1c, 1d for Lp
The outputs thereof are supplied to preamplifiers 41α and 41b via rotary transformers 38c and 38d, respectively. Also, when the output C of the AND gate 22 is 11'', the switch circuit 39α
, 39h are connected to the L side, and the outputs of the SP magnetic heads 1α, 1b are connected to the preamplifier 41 (!, 41A) via rotary transformers 38α, 38b as shown by arrows 44α, 44h.
supplied to

The switch circuit 42α is a channel switch for video signals, and the switch circuit 42A is a channel switch for PC & audio signals.

In this manner, the present invention, in a four-head VTR having an automatic SP/LP discrimination function, forcibly shifts the playback circuit to the LP mode only during the period when cueing is performed in the PCM multimode, and The LP magnetic head output without interference from adjacent tracks prevents malfunctions during cueing. In the above embodiments, an ATF type VTR or an overlap recording type VTR in which magnetic tape is wound around the cylinder at an angle of about 216° has been explained. It is clear that the method can also be applied when realizing the method.

〔Effect of the invention〕

As explained above, according to the present invention, the output of the magnetic head for LP mode is always output from the preamplifier during the period when cueing is performed in PCM multimode, so that interference from adjacent tracks is prevented. It is possible to prevent malfunctions during cueing.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a reproducing system using an embodiment of the cueing operation setting circuit of the magnetic recording/reproducing gtili according to the present invention, and FIG. 2 is a plan view showing the vicinity of the head cylinder of the magnetic recording/reproducing apparatus. FIGS. 6 and 4 are schematic diagrams showing recording track patterns, FIG. 5 is a schematic diagram showing the structure of a PCM audio signal, and FIGS. 6 and 7 are waveforms showing playback output during conventional cueing operation. FIG. 8 is a timing chart for explaining the operation of the above embodiment, and FIG. 9 is a block diagram showing another specific example of the reproduction system of the magnetic recording/reproducing apparatus using the above embodiment. 1α, 1h... SP magnetic head 1c, 1d... LP magnetic head 13... ID search circuit 14... Cue start signal input terminal 15... OR circuit 21... D flip-flop 22...ANDGATE Patent Attorney Katsoo Ogawa Figure 2 d Figure 3 Figure 5 Figure 6 (shi) Figure 7<a) (shi) Figure 8

Claims (1)

[Claims] A first head pair consisting of two magnetic heads for standard recording mode and two magnetic heads for long-time recording mode are mounted on the head cylinder.
a second head pair consisting of magnetic heads;
A first mode in which video signals and PCM audio signals are recorded and reproduced in different areas in the width direction of the magnetic tape, and a second mode in which PCM audio signals are recorded and reproduced in individual areas divided in the width direction of the magnetic tape. In the magnetic recording and reproducing apparatus that can selectively set a mode, the PCM audio signal includes at least index data for cueing for each track, and when a cueing start signal is supplied, the index data is extracted from the PCM audio signal. The first step is to detect and determine
and a second means for setting a long-time recording mode for a period from when the cue start signal is supplied until the first means outputs a cue end signal, and 1. A cueing operation setting circuit characterized in that the cueing operation setting circuit is configured to be able to cue up using.