JPS6323717B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for editing images.

Figure 1 shows the tape running state of a home VTR, and Figure 2 shows the magnetic tape pattern for continuous recording.

In FIG. 1, 1 is a rotary cylinder having a recording/reproducing head, 2 and 3 are loading pins, 4 is a tension pin, and 5 is a magnetic tape. 6 is a capstan, 7 is a pinch roller, 8 is a cassette half, 9 is a supply reel, and 10 is a take-up reel. 11 is a reel motor for fast forwarding and rewinding, 12 is a reel belt, 13 is a pulley, 14 is a roller located on the same rotation axis as the pulley and has a slip mechanism to which power is transmitted; 15
1 is an idler in which the roller 14 rolls in pressure contact with the supply reel 9 and the take-up reel 10 depending on the direction of rotation, thereby transmitting power.

Explain the following operation. When the cassette half 8 is loaded and put into the playback state, the loading pins 2 and 3 located inside the cassette half 8 move to the state shown in FIG. It is wrapped around the cylinder and contacts the image recording/reproducing head inside the cylinder.

Further, as the pinch roller 7 presses and rotates against the capstan 6, the tape 5 runs on the cylinder. Further, in order to wind the driven tape 5 onto the take-up reel 10 without slack, a take-up roller 16 is pressed against the take-up reel 10 and rotated to take up the tape 5.

Next, the operation of the conventional continuous shooting method will be explained. Possible methods of splicing are a pause mechanism during recording and a method of newly recording from a portion of an already recorded tape.

Here, we will explain the case of starting a new recording from a part of a tape that has already been recorded.When recording is started by the above operation, this spliced part will be recorded overlappingly as shown in Figure 2. The part that occurs occurs. 17 is the audio track, 20 is the control track, 18 is the video signal track of channel 1, and 19 is the channel 2.
This is the video signal track. The signals recorded on the channel 1 and channel 2 video tracks are recorded with different phases (azimuth recording), so when this tape is played back, the phase relationship between the two is disturbed before and after the spliced part. In this case, until the phase control of the servo system becomes stable in this part, a part of the track recorded by the other channel head must be reproduced, resulting in a disadvantage that the S/N ratio of the image deteriorates and becomes difficult to see.

An object of the present invention is to eliminate the drawbacks of the prior art described above, and to eliminate noise that is difficult to see in the continuous shot portion, S/N deterioration of the image, etc. during playback.

In order to achieve the above object, the present invention provides the following features: When performing a continuous shooting operation, before starting a recording operation,
Playback detected on the tape after performing a playback operation
Synchronize the CTL signal and newly recorded recording CTL,
After applying reverse rotation or acceleration torque to the capstan motor for a time corresponding to the phase difference between the two and changing the magnetic tape speed, the comparison signal of the phase control system of the capstan servo is preset for both. By doing so, the phase servo is stabilized and recording is started.

An embodiment of the present invention is shown in FIG. 3, and a timing chart for explaining the operation of FIG. 3 is shown in FIG.

In FIG. 3, 22 is an input terminal for a recording CTL signal, 23 is a recording CTL amplifier, 24 is a semiconductor switch, and 25 is a reproduction CTL amplifier. 26 is an AND gate, 27 is an RS-flip-flop,
28 is a differential circuit, and 29 is an RS-flip-flop. 30 is a recording switch, 31 is a delay circuit,
32 is an output terminal for a recording start signal, and 33 is a differential circuit. 34 is a reference oscillator using a crystal or the like, 35 is a frequency divider, 36 is a trapezoidal wave generator, 40
is a motor drive circuit, 41 is a capstan motor interlocked with the capstan shaft 6, 38 is a frequency generator generated as the capstan motor 41 rotates, 39 is a frequency divider, and 37 is a sampling hold circuit. show. Other than that, the same symbols as in FIG. 1 represent the same parts.

The operation of this circuit will be explained using the timing chart shown in FIG. When the recording switch 30 is operated to start recording, the output of the switch 30 becomes a waveform 42 in FIG. 4. This waveform 42 is passed through a delay circuit 31 to obtain a waveform 43. This delayed signal causes the magnetic recording and reproducing device to start recording. This delay time is set to a time necessary to perform the following operation to prevent the above-mentioned continuous shot images from being disturbed. During this period, the magnetic tape 5 is run at a constant speed by the capstor motor 41, the CTL signal recorded on the magnetic tape is reproduced by the CTL head 21, and the waveform 44 is transmitted via the regeneration CTL amplifier 25.
get. This signal and the output (waveform 42) of the recording switch 30 are combined into a waveform 45 by an AND gate 26.
get. Next, this waveform 45 is connected to the set terminal of the RS flip-flop 27, and the recording switch 3 is connected to the set terminal of the RS-flip-flop 27.
An output of 0 (waveform 42) is inputted to each reset terminal to obtain an output waveform 46. At this time, the R-S flip-flop 27 operates at the falling timing, and the reset signal is reset when the output of the recording switch 30 falls or when the power is turned on. This output waveform 46 is passed through a differentiating circuit 28 to obtain a waveform 47. Waveform 4 obtained by recording this waveform 47 and the vertical synchronization signal extracted from the recorded video signal applied to the terminal 22 via the CTL amplifier 23
A waveform 49 is obtained by an RS flip-flop 29 which receives a signal 8 as an input. This waveform 49 is a signal waveform with a pulse width corresponding to the phase difference between the reproduction CTL signal recorded on the tape and the newly recorded recording CTL signal.

This signal is passed through the capstan motor drive circuit 40 to cause a current to flow through the capstan motor 41 for a period of the above pulse width such that the maximum torque in the reverse direction is generated. This changes the tape running speed by rapidly slowing down the rotational speed of the capstan motor, thereby changing the phase of the reproduced CTL signal. As described above, the phase difference between the two is instantly improved, and at the rising timing of the waveform 43 at which recording starts, the phases of the reproduced CTL signal and the recorded CTL signal are almost matched, and a new recording is performed with the phase of the already recorded channel track. It is possible to record without phase disturbance of the channel track.

To control the speed of the capstan motor at this time, the output of the reference oscillator 34 is frequency-divided to 30Hz by a frequency divider 35, and this waveform is generated by a trapezoidal wave generator 36 composed of an integrating circuit or the like to generate a trapezoidal wave. . On the other hand, the capstan rotation speed generated as the capstan motor rotates is detected by the frequency generator 38, this output signal is divided by the frequency divider 39, and the trapezoidal wave is sampled and held by the sampling hold circuit 37 using this signal. This is then applied to the motor drive circuit 40 as a speed control signal to configure a servo system. The output waveforms of the reference oscillator 34, frequency divider 35, and trapezoidal wave generator 36 at this time are shown in waveforms 50, 51, and 52 in FIG. In addition, the output waveforms of the frequency generator 38, frequency divider 39, and sampling hold circuit 37 are converted into waveforms 55, 54, and 53.
Shown below.

As shown in FIG. 4, the output waveform 55 of the frequency generator 38 is generated by the capstan reversal signal shown in the waveform 49.
Since the frequency of the servo system rapidly decreases and the sampling and hold output waveform voltage 53 is greatly disturbed, if recording is started in this state, the recording track will be disturbed for the time until the servo system is pulled in, causing disturbances in the reproduced image and worsening of audio wow and flutter. Therefore, by resetting or presetting the frequency dividers 35 and 39 to appropriate values using the pulse obtained by the differentiating circuit 33 shown in FIG. By instantly pulling the output into a stable state,
It is possible to improve image connections and audio wow/fluttering.

As described above, according to the present invention, when several recordings are concatenated at different times on one tape, the video signal continues accurately at the concatenated portion, so that the image does not change at the concatenated portion during playback. Disturbance, S/N
You can obtain high-quality images without any deterioration.

[Brief explanation of the drawing]

Figure 1 is a plan view showing the tape running system of a VTR.
FIG. 2 is a plan view of a tape pattern when continuous recording is performed, FIG. 3 is a block diagram showing an embodiment of the present invention, and FIG. 4 is a timing chart for explaining the operation. 1... Rotating cylinder, 5... Magnetic tape, 6...
... Capstan, 25 ... Reproduction CTL amplifier, 2
6...AND gate, 27, 29...RS flip-flop, 28, 33...differentiation circuit, 34...
Reference oscillator, 35, 39... Frequency divider, 36... Trapezoidal wave generator, 37... Sample hold circuit, 4
0...Motor drive circuit.

Claims (1)

[Claims] 1. A reference oscillator that generates a reference output signal, a first frequency divider that divides the frequency of an output signal generated by the reference oscillator, and a capstan motor and a capstan motor. a frequency generator that generates an output signal proportional to the rotational speed of the motor; a second frequency divider that divides the output signal of the frequency generator;
A magnetic recording/reproducing device having a capstan servo circuit comprising a frequency divider and a drive means for driving a capstan motor using an output signal from the second frequency divider, a first control signal for a first video signal that has already been recorded on the magnetic tape, and a second control signal for a second video signal that is newly recorded on the magnetic tape following the first video signal. a signal generating means that receives a signal, generates an output signal having a time width according to a phase difference between the two, and supplies the signal to the driving means, and as the phase difference between the first and second control signals decreases. a delay circuit that delays a start signal for starting recording of the second video signal onto the magnetic tape by a necessary predetermined time and generates the delayed start signal; 1. A magnetic recording/reproducing apparatus comprising a reset means for resetting the first and second frequency dividers in response to a start signal.