JPH05304649A - Recorder - Google Patents

Abstract

PURPOSE:To have the continuity of the repetition of odd and even fields at the time of an edition by controlling a servo reference signal so that the odd and even field signals of a video signal can synchronize with a switching pulse for switching a recording signal to be supplied to a rotary magnetic head. CONSTITUTION:The servo reference signal is compared with a PG pulse whose waveform is shaped by a phase servo signal preparing circuit 3, and a phase servo signal corresponding to the phase difference is supplied to an adding circuit 4. And also, an FG pulse from a frequency generator is supplied through a waveform preparing circuit 5 to a speed servo signal preparing circuit 6, and a speed servo signal of a size corresponding to the rotational speed of rotary magnetic heads 1a and 1b is supplied to the circuit 4. The output signal of the circuit 4 is supplied to a motor driving circuit 7, and the rotational phase and rotational speed of the heads la and 1b are controlled by the output. And also, the PG pulse is supplied to a switching pulse preparing circuit 8, and a pulse 8a for a signal switching is prepared based on the PG pulse by the circuit 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus suitable for use in, for example, a home video tape recorder.

[0002]

2. Description of the Related Art Generally, when a video tape is edited, pre-roll editing is performed. In this pre-roll editing, the editing start point (I
Rewinding (pre-rolling) to a certain length before N point), and then phase control is performed from the pre-roll point to this IN point.

This phase adjustment control is generally performed by a capstan servo system, and is performed by forcibly adjusting a fixed voltage to a stable control voltage. At this time, the stable state of the capstan servo system collapses, and a reproduced image is reproduced. The waveform of the signal is distorted.

A time code or the like is required to compensate for the waveform distortion of the reproduced video signal, and a function of detecting framing information such as color frame pulses (including even field and odd field) from a magnetic tape for editing is provided. is necessary.

However, a simple home video tape recorder or the like does not have a time code or the like and does not have a function of detecting framing information from a magnetic tape. Therefore, this simple home video tape recorder or the like is used. When editing with, there is a disadvantage that the probability of maintaining the continuity of repeating the odd field and the even field as well as the color framing is 1/2.

In view of such a point, the present invention has a simple structure,
The purpose is to ensure that the continuity of repetition of odd fields and even fields is maintained during editing.

[0007]

The recording apparatus of the present invention, as shown in FIG. 1, for example, shows the odd-even field phase of the input video signal in the still state after pre-rolling from the editing start point of the tape-shaped record carrier during editing. The rotary magnetic heads 1a and 1b for recording on the tape-shaped record carrier are compared with the phase of a switching pulse for switching signals, and the rotary magnetic heads 1a and 1b are arranged so that both phases have a predetermined relationship.
The servo reference signal of b is controlled.

[0008]

According to the present invention, the phase of the odd-even field of the input video signal and the rotary magnetic heads 1a and 1 in the still state after prerolling from the editing start point of the tape-shaped record carrier during editing.
Since the servo reference signals of the rotary magnetic heads 1a and 1b are controlled so that the relationship with the phase of the switching pulse for signal switching of b becomes a predetermined phase relationship,
It is possible to reliably maintain the continuity of the odd and even fields during editing.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the recording apparatus of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a drum device. The drum device 1 is provided with two rotary magnetic heads 1a and 1b having different azimuths arranged at positions separated by 180 degrees from each other. Oblique tracks are alternately formed on the magnetic tape by the rotary magnetic heads 1a and 1b so that a video signal is recorded.

Further, the drum device 1 has, for example, one PG for one rotation, which indicates the phase of the rotary magnetic heads 1a and 1b.
A PG device for generating a pulse is provided, and a frequency generator for generating an FG pulse indicating the rotational speed of the rotary magnetic heads 1a and 1b is provided.

The PG pulse from the PG device of the drum device 1 is supplied to the phase servo signal forming circuit 3 via the waveform shaping circuit 2 and the phase servo signal forming circuit 3 is supplied with a servo reference signal which will be described later. In the phase servo signal forming circuit 3, the servo reference signal is compared with the waveform-shaped PG pulse, and the phase servo signal corresponding to the phase error is supplied to the adding circuit 4.

Further, the FG pulse from the frequency generator of the drum device 1 is supplied to the speed servo signal forming circuit 6 via the waveform shaping circuit 5, and in the speed servo signal forming circuit 6, the rotary magnetic heads 1a and 1b. The speed servo signal having a magnitude corresponding to the rotation speed of is obtained, and this speed servo signal is supplied to the adding circuit 4.

The output signal of the adder circuit 4 is supplied to the motor drive circuit 7 and is supplied to the motor drive circuit 7, and the output signal of the motor drive circuit 7 is supplied to the rotary magnetic head 1a.
And 1b are supplied to a motor for controlling the rotation of the magnetic heads 1a and 1b so as to control the rotational phase and rotational speed of the rotary magnetic heads 1a and 1b.

Further, the PG pulse obtained by the PG device of the drum device 1 is supplied to a switching pulse forming circuit 8 which forms a switching pulse for switching the supply of the recording signal to the rotary magnetic heads 1a and 1b at the time of recording. The switching pulse forming circuit 8 supplies the switching pulse forming circuit 8 with a switching pulse 8s as shown in FIG. 2D for switching the signal based on the PG pulse.
To form. Reference numeral 8a denotes a switching pulse output terminal for supplying the switching pulse forming circuit 8 with the switching pulse 8s to the recording signal switching circuit.

In this example, the switching pulse 8s obtained by the switching pulse forming circuit 8 is supplied to one input terminal of the phase comparison circuit 9 which operates as a gate circuit.

Further, in FIG. 1, reference numeral 10 denotes a video signal input terminal to which a video signal to be edited and inserted is supplied, and the video signal supplied to the video signal input terminal 10 is supplied to the cycle separation circuit 11. In the period separation circuit 11, the odd field period is high level "1" and the even field period is low level "0" as shown in FIG. 2A.
The odd-even field signal 11a is obtained and the vertical synchronizing signal 11b as shown in FIG. 2C is obtained.

In this example, the vertical synchronizing signal 11b obtained by the synchronizing separation circuit 11 is supplied to the recording side fixed contact 13R of the changeover switch 13 which is controlled by the microcomputer 12 to be described later. The reproduction side fixed contact 13D of the changeover switch 13 is in an electrically floating state.

The movable contact 13a of the changeover switch 13 is supplied to a reset terminal of a frequency divider 14 which is composed of a counter for forming a servo reference signal for phase servo.

Reference numeral 16 denotes a subcarrier signal input terminal to which the subcarrier signal fsc from the reference oscillator is supplied, and the subcarrier signal f supplied to the subcarrier signal input terminal 16 is supplied.
sc is supplied to a frequency divider 14 composed of a counter that divides this subcarrier signal to a vertical frequency of, for example, 60 Hz, and the signal obtained at the output side of this frequency divider 14 is used as a servo reference signal, and the phase servo signal forming circuit 3 To be supplied to.

In the present example, the odd-even field signal 11a obtained by the sync separation circuit 11 is supplied to the window forming circuit 17. In the window forming circuit 17, as shown in FIG. 2B, the odd-even field signal 11a is generated.
Window signal 17 of a certain width that gates the rising edge of
a is obtained, and this window signal 17a is supplied to the other input terminal of the phase comparison circuit 9.

The phase comparison circuit 9 compares the phases of the window signal 17a and the switching pulse 8s, and when the rising edge of the switching pulse 8s enters the window period of the window signal 17a, it goes high as shown in FIG. 2E. The level signal "1" is output and this high level signal "1" is supplied to the microcomputer.

In this case, in this example, the window signal 17a and the switching pulse 8s of the phase comparison circuit 9 are used.
Phase comparison is than carried out in Suchiirumodo after pre-roll, generally rotary magnetic head 1a of the drum device 1 for correcting the horizontal frequency f _H in this Suchiirumodo with
And the rotation speed of 1b is several percent (for example, -0.38 in still play mode of 8 mm video tape recorder).
%) Late. Therefore, once every few seconds, the rising portion of the switching pulse 8s always has a chance to enter the window signal 17a, and even if control for changing the rotation speeds of the rotary magnetic heads 1a and 1b is not added, The high level signal "1" can be obtained at the output side of the phase comparison circuit 9 only by waiting for a few seconds.

This high-level signal "1" indicates that the microcomputer 12
, The movable contact 13a of the changeover switch 13 is connected to the recording side fixed contact 13R by the microcomputer 12 (see FIG. 2F). At this time, the vertical synchronizing signal obtained from the video signal from the video signal input terminal 10 is supplied. 11b is supplied as a reset signal to the frequency divider 14 including a counter, and the frequency divider 14 is reset.

In this case, since the output signal of the frequency divider 14 is used as the servo reference signal of the phase servo signal forming circuit 3, the odd / even field signal 11a and the switching pulse 8s are used.
And the phase can be made to have a constant phase relationship.

Therefore, at the time of editing, the odd-even field signal 11a and the switching pulse 8s are locked in the same phase in the still state at the pre-roll point after pre-roll as described above, and the capstan is started up in this state to edit. By setting the recording mode at the IN point of the start point, it is possible to continuously record the odd field and the even field.

That is, FIG. 3 shows a flow chart at the time of this editing. At the time of this editing, the editing start point (I
A so-called pre-roll for rewinding for a predetermined length from (N point) is performed to determine whether or not it is the pre-roll point (step S1).

When the pre-roll point is reached, a window signal 17a formed from an odd-even field signal 11a obtained from an external video signal edited by the phase comparison circuit 9 in FIG. 1 and the rotational phase of the rotary magnetic heads 1a and 1b. Indicating P
By comparing the phase with the switching pulse 8s obtained from the G pulse, it is judged whether or not the rising portion of this switching pulse 8s has entered the window signal 17a (step S2), and when it is not, a counter for measuring time is set. After clearing (step S3), when the rising portion of the switching pulse 8s enters the window signal 17a, the movable contact 13a of the changeover switch 13 is connected to the recording side fixed contact 13R (step S4), and the frequency divider 14 is connected. The external vertical synchronizing signal 11b separated from the external video signal is supplied to the reset terminal of the counter constituted by, and reset by the vertical synchronizing signal 11b.

A servo reference signal determined by the vertical synchronizing signal 11b is supplied to the phase servo signal forming circuit 3 to control the rotational phases of the rotary magnetic heads 1a and 1b so as to synchronize with the servo reference signal.

From the time when the vertical synchronizing signal 11b is supplied as a reset signal to the frequency divider 14, it takes a predetermined time T until the rotational phases of the rotary magnetic heads 1a and 1b are synchronized with the servo reference signal. Is counted by the counter (step S5), it is judged whether or not this predetermined time T has passed (step S6), and when this predetermined time T has passed, the capstan which runs the video tape at a constant speed is started up and the video tape is run. Then, when the editing start point (IN point) is reached, the recording mode is set and recording is performed on the video tape by the rotary magnetic heads 1a and 1b (step S7).

In this case, since the switching pulse 8s for switching the supply of the recording signal to the rotary magnetic heads 1a and 1b and the odd / even field signal 11a of the video signal to be recorded are synchronized, the relationship between the odd field and the even field is always maintained. Can be continuous.

As described above, according to this example, the odd-even field signal 11a of the video signal and the rotary magnetic heads 1a and 1b are used.
Switching pulse 8s for switching the recording signal supplied to
There is an advantage that the continuity of the odd field and the even field at the time of editing can be surely maintained by a simple configuration in which the servo reference signal of the phase servo circuit is controlled so as to be synchronized with.

In the above embodiment, the window signal 17a is obtained from the odd-even field signal 11a, and the phase comparison circuit 9 detects whether or not the rising portion of the switching pulse 8s is included in the window signal 17a. A predetermined window signal is formed from the pulse 8s, and it is determined whether or not the rising portion of the odd-even field signal 11a is included in this window signal.
It can be easily understood that the same effects as those of the above-described embodiment can be obtained even if the detection is performed by.

Further, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0034]

According to the present invention, the odd-even field signal 11a of the video signal to be edited and the rotary magnetic head 1a.
And 1b to ensure the continuity of the odd field and the even field at the time of editing with a simple structure that only controls the servo reference signal of the phase servo circuit so as to be synchronized with the switching pulse 8s for switching the recording signal supplied to 1b. There is a profit that can

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a recording apparatus of the present invention.

FIG. 2 is a diagram for explaining the present invention.

FIG. 3 is a diagram for explaining the present invention.

[Explanation of symbols]

 1 Drum Device 1a, 1b Rotating Magnetic Head 3 Phase Servo Signal Forming Circuit 7 Motor Driving Circuit 8 Switching Pulse Forming Circuit 9 Phase Comparing Circuit 10 Video Signal Input Terminal 11 Sync Separation Circuit 12 Microcomputer 13 Changeover Switch 14 Divider 16 Sub Carrier Signal Input terminal 17 Window formation circuit

Claims (2)

[Claims] 1. In the still state after pre-rolling from the editing start point of the tape-shaped record carrier at the time of editing, the phase of the odd-even field of the input video signal and the signal switching of the rotary magnetic head for recording on the tape-shaped record carrier are performed. A recording apparatus, wherein the servo reference signal of the rotary magnetic head is controlled so that the phase of the switching pulse is compared with that of the switching pulse so that both phases have a predetermined relationship. 2. A servo of the rotary magnetic head is controlled by controlling a frequency divider for frequency-dividing the output signal of the reference oscillator with the phase comparison output signals of both phases, and using the output signal of the frequency divider as the servo reference signal. A circuit for supplying to a circuit.
Recording device.