JPH0690822B2 - Magnetic recording / reproducing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oblique scanning type magnetic recording / reproducing apparatus, that is, a VTR (video tape recorder) for recording / reproducing a composite video signal or an information signal containing a synchronizing signal, and more specifically to a predetermined tape. The present invention relates to a magnetic recording / reproducing apparatus having a function of recording a tape position marking signal (cue signal) suitable for performing a cueing operation for obtaining a stop mode, a still image mode, etc. at a position.

[0002]

2. Description of the Related Art There are two conventional magnetic tapes for commercial VTRs.
Often there is one audio track. For this reason, when there are two audio tracks, a tape position marking signal (cue signal) for cueing may be recorded on one audio track. In this case, the audio signal in the portion where the marking signal was recorded is erased, but there was another audio track, so there was no practical problem.

[0003]

However, since a tape of a small VTR generally has only one audio track, if the marking signal is recorded on the audio track, the audio signal is erased. Therefore, if the audio signal is not desired to be erased, it is impossible to record the marking signal. It is possible to provide a dedicated track for recording a marking signal in order to solve this kind of problem, but inevitably the VTR becomes large, complicated and expensive.

Recording a cue signal or a marking signal together with a control signal on a control track is disclosed in, for example, Japanese Patent Publication No. 54-23804 and Japanese Utility Model Publication 55.
No. 174789 is disclosed. In addition , the method of recording the marking signal in the reproduction mode is actually developed.
It is disclosed in Japanese Patent No. 66219. But open here
In the system shown, the control signal (CTL signal)
Within 10msec from the leading edge of the
A marking signal is arranged. For this reason,
Even if there is no problem when driving
The wrong signal as the leading edge of the control signal,
There is a risk that the leading edge of the control signal of the rule may not be detected.
There is.

Therefore, it is an object of the present invention to record a marking signal in the reproduction mode and to perform reverse reproduction.
Even when the control signal and the marking signal are detected,
It is an object of the present invention to provide a magnetic recording / reproducing device that can reliably perform output .

[0006]

According to the present invention for achieving the above object, a magnetic tape is obliquely scanned by a rotary head to record a composite video signal or information signal including a synchronization signal.
And reproducing, and scanning a control track extending in the longitudinal direction of the magnetic tape with a fixed control head to record a control signal corresponding to the synchronization signal.
And a mark indicating the position of the magnetic tape while reproducing.
A recording signal on the control track and
In a diagonal scanning type magnetic recording / reproducing apparatus configured to reproduce, a vertical sync signal is separated from a composite video signal to be recorded.
Vertical synchronization signal separation circuit and the vertical synchronization signal separation circuit
1 of the vertical sync signal in response to the vertical sync signal separated by
Longer than the cycle (1 field), 2 rounds of vertical sync signal
Has a pulse width shorter than the period (1 frame) and has a trailing edge
Is a square wave pulse separated by a predetermined distance from the vertical sync signal.
Generated as a recording control signal, and in recording mode
The recording control signal to the control head.
A pulse generation circuit for a recording control signal supplied to
And a control signal detection circuit connected to the control head, and obtained from the control signal detection circuit.
Of a predetermined time width in response to the trailing edge of the reproduced control signal.
Marking for generating pulse for marking signal section indication
A pulse generating circuit for instructing a signal section and a marking instruction signal for inputting a marking instruction signal for instructing to record the marking signal on the control track.
A signal input terminal, said Ma - King signal section indicating pulse onset
Connected to the raw circuit and the marking instruction signal input terminal, the marking instruction signal and the marking signal section
The marking signal section instruction based on the instruction pulse
A marking signal generated in the period of use pulse, and a marking signal recording circuit for supplying a marking signal to the control head, the reproduction control -
Is separated from the leading edge of the signal
The marking signal does not interfere with the leading edge of the
The position of the marking signal section indicating pulse is
The present invention relates to a magnetic recording / reproducing apparatus characterized by being set . The correspondence between the present invention and the embodiment will be described. The recording control signal pulse generation circuit is a mono-multivibrator 13, and the control signal detection circuit is the reference numerals 23, 24, 25 in FIG. And 26, the marking signal section designating pulse generating circuit is a mono-multivibrator 28, the marking designating signal input terminal is a marking trigger signal input terminal 14, and the marking is The signal recording circuit is denoted by reference numerals 15 and 1 in FIG.
It is a part shown by 6, 17, and 18.

[0007]

The marking signal in the present invention is a signal indicating a predetermined position of the magnetic tape, such as a signal indicating a still image reproducing device and a signal indicating a stop position. The control signal detection circuit generates a signal indicating the time position of the control signal necessary for determining the recording position of the marking signal.
The marking signal recording circuit determines the position of the marking signal based on the reproduction control signal.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a VTR according to an embodiment of the present invention will be described with reference to FIGS. VT of this embodiment
R has the same structure as a general-purpose small VTR of a diagonal scanning type for home use, a mechanism for pulling out the tape 1 from a cassette (not shown), a drum for guiding the tape 1 obliquely, and a head drum for rotating a pair of video heads. , A capstan, a pinch roller, a reel drive mechanism and the like are provided. The tape 1 has a diagonal video track 2,
It has one audio track 3 and one control track 4 extending in the longitudinal direction of the tape 1. A fixedly arranged audio head 5 faces the audio track 3, and a fixedly arranged control head 6 faces the control track 4. The audio head 5 and the control head 6 are the tape 1
Since it is arranged in the horizontal traveling section of, the tape is scanned horizontally along the tape traveling direction shown by the arrow 7. On the other hand, since a video head (not shown), that is, a rotary head, is in contact with the tape 1 running obliquely while being rotated by the head drum, it scans obliquely as indicated by an arrow 8.

Reference numeral 9 denotes a head drum servo circuit for controlling a head motor (not shown) for rotating the video head, which is controlled by a control signal.
Reference numeral 10 denotes a tape running control circuit, which controls a tape running system such as a reel motor and a capstan to a state according to each mode such as forward constant speed running, forward fast forward, backward fast forward, still image, and stop. Circuit. Therefore, the tape running control circuit 10 sets each mode in response to a manual mode setting operation switch, and also responds to a tape position marking signal (cue signal) related to the present invention to stop mode or still image mode. Etc. are set.

In order to obtain a reproduction control signal and a reproduction marking signal to be supplied to the head drum servo circuit 9 and the tape running control circuit 10, the control head 6 has a control signal recording circuit, a marking signal recording circuit, a control signal and a control signal. A marking signal detection circuit is connected.

The control signal recording circuit includes a vertical synchronizing signal separating circuit 12 connected to an input terminal 11 to which an NTSC composite video signal is input, and a vertical synchronizing signal of FIG. 2A obtained from the separating circuit 12. 2B in FIG. 2B in response to the leading edge of the first mono-multivibrator 13 shown by MMV for generating a rectangular wave having a pulse width T2 in a period T1.

The marking signal recording circuit responds to the trigger signal (marking instruction signal) supplied from the marking trigger signal input terminal 14 from t2 shown in (C) of FIG.
A second mono-multivibrator 15 for generating a negative pulse having a width T3 of t9 and two mono-multivibrators 1
The AND gate 16 of the inverting input type having the NOR gate function which inputs the inverting outputs of 3 and 15 respectively, and the AND gate 16 of FIG. A third mono-multivibrator 17 for generating a pulse of time width T4 of (E) and a recording marking of time width T5 of FIG. 2 (F) triggered by the trailing edge of the pulse obtained from this mono-multivibrator 17 And a fourth mono-multivibrator 18 for generating a signal. In order to combine the recording control signal and the recording marking signal and supply them to the control head 6, an OR gate 19 to which both signals are input is provided, and this gate 19 is connected to the control head 6 via the capacitor 20. Has been done. Further, a first changeover switch 21 is provided between the first mono-multivibrator 13 and the OR gate 19 to enable the marking signal to be recorded in both the recording mode and the reproduction mode,
When one input line of the OR gate 19 is in the recording mode, the first mono-multi vibrator 13 is connected via the contact REC.
And is grounded via a contact PB in the reproduction mode. Further, a second changeover switch 22 interlocking with the switch 21 is provided between the output terminal of the first mono-multivibrator 13 and one input terminal of the input inverting type AND gate 16, and the contact REC is connected in the recording mode. The output of the mono multivibrator 13 is input to the input inversion type AND gate 16 via the contact P in the reproduction mode.
A signal indicating the marking signal section determined based on the reproduction output is input via B.

The control signal and marking signal detection circuit selects the output of the amplifier 23 by the forward direction amplifier 23 coupled to the control head 6, the reverse direction inverting amplifier 24, and the contact FWD at the time of traveling in the forward direction. , A changeover switch 25 for selecting the output of the inverting amplifier 24 at the contact REV when traveling in the reverse direction, a negative differential pulse formation extraction circuit 26 and a positive differential pulse formation extraction circuit 27 connected to the output stage of the switch 25, and a negative differential A variable pulse width fifth mono-multivibrator 28 for generating a pulse having a time width T6 shown in FIG. 2 (J) in response to the pulse shown in FIG. 2 (I) obtained from the pulse forming / extracting circuit 26, The output of the mono multivibrator 28 is inverted (K) in FIG.
29, a control for inputting the output of the fifth mono-multivibrator 28 shown in FIG. 2 (J) and the output of FIG. 2 (L) obtained from the positive differential pulse formation extraction circuit 27. AND gate 30 for signal detection
And an AND gate 31 for detecting a marking signal, which receives the output of the inverter 29 of FIG. 2 (K) and the output of the positive differential pulse formation extraction circuit 27 of (L) of FIG.
It comprises a marking detection counter 32 which is provided at the output stage of the D gate 31 and which outputs a marking detection output when three reproduction marking signals of FIG. 2 (N) are detected. The output line of the counter 32 is the tape running control circuit 1
0, the output line of the AND gate 30 is connected to the servo circuit 9, and the output line 33 of the fifth monomultivibrator 28 is also connected to the contact PB of the changeover switch 22. Further, there is provided a time constant variable resistor 34 for changing the output pulse width T6 of the fifth mono-multivibrator 28 according to the tape speed during reproduction.

Next, the recording / reproducing operation of the marking signal and the control signal will be described. When the marking signal is not recorded, the trigger signal is not given to the trigger input terminal 14, so that the trigger input terminal 14 is not recorded.
The signal as shown in (F) is not generated. Therefore, only the control signal having the pulse width T2 shown in FIG. 2B is supplied to the control head 6 in the cycle T1. Figure 2
In order to make the repetition frequency of the control signal of (B) of (1) to be 1/2 of the repetition frequency of the vertical synchronizing signal (frame synchronizing signal), the pulse width T2 is set to the cycle of the vertical synchronizing signal (about 1
6.6 msec) and the period T1
It is set smaller. As described above, in the case of recording only the control signal, only the control signal is detected even in the reproduction mode, and the control of FIG. 2M generated corresponding to the leading edge of the pulse of FIG. The signal is sent to the servo circuit 9.

When the marking signal is recorded in the recording mode, the marking trigger signal is supplied to the input terminal 14 at time t2 in FIG. 2 corresponding to the desired tape position. As a result, a negative pulse having a time width T3 (about 100 msec) which is about three times as long as the period T1 of the control signal shown in FIG. 2B is applied to the second monomultivibrator 15 in the interval t2 to t9.
Arises from. Since the mode is the recording mode, the outputs of the first and second mono-multivibrators 13 and 15, that is, the signals of (B) and (C) of FIG. A logical product output of the signals is provided as shown in FIG. The pulse of (D) of FIG. 2 designates the section in which the marking signal is recorded. In this embodiment, the time from the trailing edge of the control signal of (B) of FIG. 2 to the leading edge of the next control signal. A positive pulse having a width occurs three times. The third monostable multivibrator 17 responds to the leading edge of the pulse of FIG. 2D to generate the pulse of the time width T4 of FIG. 2E, and responds to the trailing edge of this pulse to generate the fourth pulse. Mono Multi Vibrator 18
A pulse having a time width T5 shown in FIG. That is, the recording marking signal is generated after the trailing edge of the control signal shown in FIG. 2B by the time width T4. The recording control signal of FIG. 2B and the recording marking signal of FIG. 2F are added by the OR gate 19 to become the signal of FIG. 2G, which is the control track 6 by the control head 6. Recorded in. That is, the marking signal is recorded in the vicinity of the trailing edge of the control signal so as not to interfere with the control signal.

When the marking signal is detected by normal running or high speed running (fast forward) of the tape 1 on which the marking signal is recorded, the contact point FW of the changeover switch 25 is detected.
D is closed, the tape 1 is run in the forward direction, and the control head 6 scans the control track 4. As a result, a reproduction output is obtained from the control head 6 in the state of the differential waveform shown in FIG. If the reproduction output containing both the control signal component and the marking signal component is passed through the negative differential pulse formation extraction circuit 26 composed of the capacitor C1, the resistor R1 and the diode D1, FIG.
The negative differential pulse shown in (I) is extracted. That is, the pulse indicating the time t4 corresponding to the trailing edge of the recording control signal can be extracted. On the other hand, the positive differential pulse shown in (L) of FIG. 2 is obtained at the output stage of the positive differential pulse forming and extracting circuit 27 including the capacitor C2, the resistor R2 and the diode D2. That is, it is possible to obtain the output of (L) of FIG. 2 which includes the differential pulses indicating the leading edge of the recording control signal and the leading edge of the recording marking signal, respectively. The reproduction control signal and t5 at time t1 in (L) of FIG.
Since it is necessary to detect the reproduction marking signal at the time point separately, the fifth differential vibrator 28 is triggered by the negative differential pulse in (I) of FIG. 2 and the time interval t4 to t6 between the two negative differential pulses is increased. A negative pulse having a large time width T6 is generated as shown in FIG. Then, the negative pulse of (J) of FIG. 2 is inverted by the inverter 29, and the negative pulse of (K) of FIG. 2 is input to the AND gate 31. When the AND gate 31 is opened only for the time of t4 to t7,
Only the positive differential pulse at time t5 in FIG. 2L passes through this, and the reproduction control signal shown in FIG. 2N is obtained at the output line of the AND gate 31. In addition,
Since the time width T6 of the mono-multivibrator 28 is set to a value that does not reach the time point t8, the positive pulse at the time point t8 does not pass through the AND gate 31. In this embodiment, since the marking signal is recorded three times,
Three marking pulses are generated as shown in (N) of
This is input to the marking detection counter 32, and when three marking pulses are counted, a marking detection output is generated, the tape running control circuit 10 enters, for example, the stop mode, and the cue or search of the desired recording portion is completed. On the other hand, FIG.
Since the signals (J) and (L) are input, the reproduction marking signal cannot pass through the gate 30 at the time t5.
Only the reproduction control signals at time points 1 and t8 are output from the AND gate 30 and supplied to the head drum servo circuit 9 as shown in FIG.

When the tape 1 is run in the reverse direction and the marking signal is detected, the changeover switch 25 is set to the contact REV.
Throw in. As a result, the output of the control head 6 which has become the opposite pole due to the backward traveling is returned to the same pole as during the forward traveling, and the marking signal and the control signal can be detected in the same manner as during the forward traveling.

When the tape speed is changed at the time of detecting the marking signal, the time constant of the fifth mono-multivibrator 28 is changed by the resistor 34 in association with the change of the tape speed, and the output of FIG. The pulse width T6 is kept in a constant relationship with the cycle of the reproduction control signal. That is,
The time width T6 is set so as to extract the marking signal at time t5 regardless of the change in tape running speed.

In the reproducing mode, when recording the marking signal, the switches 21 and 22 are turned on to the contacts PB, respectively. As a result, the signal shown in (J) of FIG. 2 and the signal shown in (C) of FIG. 2 are input to the input inversion type AND gate 16, and as a result, as shown by the dotted line in (D) of FIG. An output having a pulse width is obtained, and based on this, the pulses shown in (E) and (F) of FIG. 2 are sequentially obtained, and the marking signal of (F) of FIG. Will be recorded.

As is clear from the above, in this embodiment,
Since the output of the fifth mono multivibrator 28 is used for forming the marking signal during reproduction, the marking signal can be easily recorded during reproduction. Therefore, the marking signal can be easily recorded while watching the reproduced image. Further, since the time constant of the fifth mono-multivibrator 28 is changed corresponding to the change of the tape speed, and the time width T6 of the output pulse is set to the width at which the marking signal can be detected, marking is performed at the tape speed from low speed to high speed The signal can be detected. Therefore, it is possible to locate the recording area by the marking signal at various tape speeds. In addition, since the marking signal can be detected even when traveling in the reverse direction, it is possible to quickly find the beginning of the marking signal or the like. Also, using the trailing edge of the control signal to form the marking signal,
Since the recording signal is recorded, it is easy to record the marking signal without disturbing the control signal. In addition, the marking signal is recorded multiple times (three times),
At the time of reproduction, the marking detection output is based on a plurality of detections, so that highly reliable marking operation is possible.

The embodiments of the present invention have been described above.
The present invention is not limited to this, but can be modified. For example, the present invention can be applied to the case where the video signal and the non-video information signal are alternately recorded every one horizontal scanning period or one vertical scanning period. It is also applicable to a case where non-video information such as measurement data is arranged and recorded in a television signal format. Alternatively, a trigger signal for generating a marking signal may be generated at a constant cycle, and the marking signal may be recorded on the control track 4 at a constant cycle. In addition, the marking signal is shown in Figure 2.
Not only one is generated at t5 as shown in (N) of
You may make it generate | occur | produce further in this vicinity. Further, the marking signal may be a digital signal and may include information such as stop and still images.

[0022]

According to the present invention, the recording control signal is obtained.
Is equipped with a pulse generator circuit for recording control signals.
The trailing edge of the vertical line from the vertical sync signal by a predetermined distance, and
Marking with reference to the trailing edge of the playback control signal
Create a pulse for signal section indication and mark in this section.
Since signals are arranged, forward playback and reverse playback
In either case, the marking signal and the reproduction control
It is now possible to accurately achieve the distinction between the signal and the leading edge.
It

[Brief description of drawings]

FIG. 1 is a block diagram showing a part of a VTR according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing the states of points A to N in FIG.

[Explanation of symbols]

 1 tape 6 control head 14 marking trigger signal input circuit

Claims (1)

[Claims] 1. A serial composite video signal or information signal including a synchronization signal and obliquely scanned by the magnetic tape rotation head
Recording and play, serial control signal corresponding to the scanning the synchronization signal in the magnetic tape longitudinally extending control track fixed control head the
A marker indicating the position of the magnetic tape while recording and reproducing.
King signal is recorded and recorded on the control track.
In a diagonal scanning type magnetic recording / reproducing apparatus configured to reproduce and reproduce, a vertical sync signal is separated from a composite video signal to be recorded.
Vertical synchronization signal separation circuit and the vertical synchronization signal separation circuit
1 of the vertical sync signal in response to the vertical sync signal separated by
Longer than the cycle (1 field), 2 rounds of vertical sync signal
Has a pulse width shorter than the period (1 frame) and has a trailing edge
Is a square wave pulse separated by a predetermined distance from the vertical sync signal.
Generated as a recording control signal, and in recording mode
The recording control signal to the control head.
A pulse generation circuit for a recording control signal supplied to
And a control signal detection circuit connected to the control head, and obtained from the control signal detection circuit.
Playback control - response to Jo Tokoro time width at the trailing edge of the Le signal
Marking for generating pulse for marking signal section indication
A pulse generating circuit for instructing a signal section and a marking instruction signal for inputting a marking instruction signal for instructing to record the marking signal on the control track.
A signal input terminal, said Ma - King signal section indicating pulse onset
Connected to the raw circuit and the marking instruction signal input terminal, the marking instruction signal and the marking signal section
The marking signal section instruction based on the instruction pulse
The markings signals generated in the period of use pulse, and a marking signal recording circuit for supplying a marking signal to the control head, the reproduction control -
Is separated from the leading edge of the signal
The marking signal does not interfere with the leading edge of the
The position of the marking signal section indicating pulse is
A magnetic recording / reproducing apparatus characterized by being set .