CN85101070A - Editing servo method - Google Patents

Abstract

The present invention is: recording the monitoring signal of image tracking, detecting the tracking error from the regenerated monitoring signal, and performing the compilation and editing of the 8mm image of the world unified standard for automatic tracking control.

The splicing regeneration edited by Jiang Editor is to use the tracking error obtained from the aforementioned monitoring signal to control the movement of the magnetic tape, so that the control circuit of the driving wheel servo system is in a ready state. When switching to the recording state, switch the capstan servo system to control the movement of the magnetic tape, and because the aforementioned ready state is removed, image confusion will not occur at the joint, thereby providing an editing servo method.

Description

The present invention is an editing servo method for compiling and editing a magnetic recording and reproducing device.

Compilation and editing of magnetic recording and reproducing devices (VTRs), commonly known as continuous recording functions, is still indispensable for home VTRs. Especially the 8mm camera type VTR regards this function as life.

This kind of compilation editing generally involves rewinding the tape (recording medium) from the unrecorded part to the recorded part, after a short period of time (about 1 to 2 seconds) from the start of editing to the preparation state (the head servo system is in the recording state, the active The wheel servo system is in the regeneration state), and shifts to the recording state. At this time, the magnetic head servo system that controls the rotating magnetic head only needs to keep the phase synchronization with the vertical synchronization signal of the image signal to be recorded; No confusion and no deviation in the recording tempo of the control signal are necessary conditions for state switching.

Next, the operation of the capstan servo system at the time of editing will be described from the known examples shown in Fig. 1 and Fig. 2 .

Figure 1 is the main block diagram for signal processing of the driving wheel servo system. 1 is a frequency divider, 2 is a first gate circuit, 3 is a switch circuit, 4 is a delayer, 5 is a phase comparator, and 6 is a second gate circuit.

Figure 2 is a signal waveform diagram of Figure 1.

The configuration and operation in Fig. 1 will be described with reference to the waveforms in Fig. 2 . The frequency divider 1 inputs the rotation detection signal (FG signal) S ₁ of the capstan motor and divides the frequency by a frequency slightly equal to the regeneration control signal (regeneration CTL signal) S ₂ to generate the PG signal S ₃ . In the ready state ("H") during editing, the first gate circuit 2 is opened by the state switching signal _S4 , and the frequency divider 1 is reset by the regenerated CTL signal _S2 , so that the phase of the regenerated CTL signal _S2 of the PG signal _S3 The difference matches the phase within one cycle of the FG signal _S1 . The switch circuit 3 selects to switch and output the reproduced CTL signal _S2 in the ready state, and selects to switch and output the PG signal _S3 in the recording state ("L"). The output S ₅ of the switch circuit 3 is only delayed by the specified time T ₁ through the delayer 4 to form a signal S ₆ , which is compared with the trapezoidal wave signal S ₉ formed in the phase comparator 5. In the relevant phase period, the slope The center of the department is sampled. Furthermore, the reference signal (or position detection signal) _S7 of the rotary head forming the trapezoidal wave signal _S9 is matched with the phase of the reproduced CTL signal _S2 . In the ready state, the second gate circuit 6 is opened by the switching signal _S4 , and the reference signal _S7 is used as the reference input of the phase comparator 5; in the recording state, the internal reference signal generated by the phase comparator 5 itself is used as its reference input . Here, the internal reference signal is generated by using a binary counter to make the phase comparator 5 a digital phase comparison circuit, which can be easily realized by decoding its count value. The aforementioned reference signal _S7 is of course used as a recording control signal in the recording state.

With the above-mentioned structure, in the preparation state of editing, the phase error signal S ₁₀ generated by the phase comparison between the reference signal S ₇ of the rotating head and the reproduction CTL signal S ₂ tracks and controls the capstan motor; in the recording state after the state transition, the internal reference The phase error signal S ₁₀ generated by the phase comparison between the signal and the PG signal S ₃ controls the capstan motor and controls the fixed speed of the magnetic tape. Therefore, the deviation of the control signal recording tempo and the confusion of the servo system at the time of state transition can be limited to a minimum. However, in view of the composition of the prior art, because the servo system confusion during the state transition occurs in one cycle of the FG signal _S1 , when the frequency of the FG signal _S1 cannot be very high, there is a shortcoming that the servo system chaos is aggravated . When playing back the tape that has been edited and recorded, the confusion of the servo system will also occur at the joint. Due to the momentary confusion of the playback picture, when the number of edits is large, an unstable picture will be formed. Simultaneously, in the tracking during the preparation state, the regenerated CTL signal S ₂ and the reference signal S ₇ (i.e. the recording control signal) are phase-synchronized. Differences in transposition, etc.), deviations in tracking conditions, will also cause the same problem. In addition, there is still a problem that it cannot be applied to the new type of VTR that does not need to control the signal, but detects the tracking error signal according to the reproduction output of the rotary head (for example, the reproduction FM signal or the monitoring signal for tracking, etc.), and performs tracking servo control. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel VTR editing servo method that does not use a control signal.

The present invention is: in the state of recording, use the phase comparator that produces the reference signal, take the rotation detection signal of the capstan motor as the comparison signal, and carry out constant speed control on the magnetic tape according to the phase error signal obtained thereby; , perform tracking control according to the tracking error signal obtained by detecting the tracking deviation of the rotating magnetic head; in the preparation state of compilation and editing, perform tracking control according to the aforementioned tracking error signal; after transferring to the recording state, perform constant speed on the tape according to the aforementioned phase error signal Control, at the same time, in the aforementioned ready state, according to the aforementioned rotation detection signal, the aforementioned phase comparator is set at the action center value of the phase comparison; after transferring to the recording state, the aforementioned set action is also released, or Before or after the aforementioned state transition, there is at least one set action. The aforementioned phase comparator is constituted by a binary counter, and the binary counter is pre-set corresponding to the count value of the operation center value of the aforementioned phase comparison, and then the aforementioned setting action is performed. The present invention is an editing servo method having the above characteristics. The present invention provides a novel VTR editing servo method that does not use control signals.

As can be seen from the above description, the present invention is: in the preparation state of compiling and editing, the tracking control is carried out according to the tracking error signal; after transferring to the recording state, the tape constant speed control is carried out according to the phase error signal, and meanwhile, in the aforementioned preparation state, Set the phase comparator at the center value of the phase comparison action; after transitioning to the recording state, cancel the previous set action. According to the above-mentioned constitution, it is possible to prevent the confusion of the servo system at the time of state transition, and to realize reliable editing, and its practical effect is great.

Fig. 1 is the main block diagram of the driving wheel servo system when the existing assembly is edited. Fig. 2 is an operation waveform diagram of Fig. 1. Fig. 3 is an embodiment of the present invention, a basic block diagram of the main part of the servo system when compiling and editing. Fig. 4 is a waveform diagram illustrating the operation of Fig. 3 .

Fig. 3 is an embodiment of the present invention. 1 and 2 are rotating magnetic heads, which are arranged at 180° mutually on the rotating cylinder; the magnetic tape 3 wound at 180° on the rotating cylinder is used for recording or reproducing signals. 4 is a tracking error detector, 5 is a switch circuit, 6 is a frequency divider, and 7 is a phase comparator. The phase comparator 7 is composed of digital circuits, including: latching pulse generating circuit (L.P.G) 8, preset pulse generating circuit (P.P.G) 9, gate circuit 10, digital phase comparison circuit (D.P.C) 11, internal reference signal generating circuit ( R.S.G) 12.

In the above configuration, the tracking servo control is performed with the tracking error output _S4 of the tracking error detector 4 in the ready state for editing, and the phase error output _S10 of the phase comparator 7 is used after the transition to the recording state. Carry out fixed-speed servo control, in the phase comparator 7 that prevents the servo confusion when the state transfers, there are some novel techniques.

First, the reproduction output S ₁ , S 2 of the rotary head 1, ₂ and the rotation detection signal (head switching signal) S ₃ of the rotary head are input to the tracking error detector 4; The cycle monitor signal detects an error signal based on tracking deviation of the rotary head. That is: when a tracking deviation occurs, the adjacent tracking monitoring signal is also regenerated at the same time; the direction of the tracking deviation is detected by the frequency of its intermodulation distortion output and beat output; the amount of tracking deviation is detected by the output level. The tracking error signal S ₄ of the tracking error detector 4 is usually used as a tracking control signal during reproduction, and at the same time, in the preparation state during editing, the switch circuit 5 has an output S ₁₁ according to the state switching signal S ₈ , which is used for tracking control

On the other hand, when the phase comparator 7 is in the ready state, it adjusts the center value of the DPC 11 in the phase comparison operation; after transferring to the recording state, it uses the phase error signal S ₁₀ obtained by canceling the adjustment operation as a switch according to the state switching signal S ₈ . The output S ₁₁ of the circuit 5 is used for constant speed control of the magnetic tape 3 . Accordingly, it is possible to prevent the servo system from being disturbed at the time of state transition.

Next, the configuration and operation of the phase comparator 7 in the main block diagram of the present invention will be described with reference to the waveform diagram in FIG. 4 . LPG8 inputs the PG signal S 6 obtained by dividing the FG signal S ₅ of the driving wheel motor _{by 6} by the frequency divider, as well as the beat pulse S ₇ and the state switching signal S ₈ ; its output forms a blocking pulse A and a prohibition generated earlier than A timing Beat C, the latter prohibits the preset pulse B and beat pulse _S7 selected and output by the state switching signal _S8 (the state switching signal _S8 is output in the "H" ready state) during the latching operation. PPG9 inputs beat pulse _S7 and internal reference signal _S9 of RSG12 to form preset pulse D. The gate circuit 10 inputs the preset pulse B of IPG8 and the preset pulse D of PPG9 to obtain a logical sum (OR) output. EDPC11 inputs the blocking pulse A, the preset pulse B, the forbidden beat C, and the OR output E. Its usual phase comparison operation is: in the binary counter constituting DPC11, preset the initial value NP of the count with the preset pulse D, and form the digital equivalent trapezoidal wave signal as shown in Fig. 4 F. Then, the trapezoidal wave signal F is sampled according to the blocking pulse A, that is, phase comparison is performed after blocking to obtain a phase error signal S ₁₀ . Here, after the state transfer, the phase comparator 7 sets the DPC11 at the count value NC of the corresponding phase comparison action center value during the phase-locked preparation state; after the state transfer, if the blocking pulse B comes to the action center, it can prevent The chaos of the servo system. That is to say: the preset pulse B is generated in the ready state, and the preset value can be switched from the initial value NP to the central value NC by the preset pulse B. RSG12 decodes the count output of DPC11 to set value NF to obtain internal reference signal S ₉ , which is input as reference signal of PPG9.

As explained above, the present invention is: in the preparation state of editing, carry out tracking control according to the tracking error signal _S4 ; After transferring to the recording state, control the magnetic tape at a constant speed according to the phase error signal _S10 , at the same time, in the preparation state, Set the phase comparator 7 at the center value of the action, and release the set action after transferring to the recording state, so that the servo system confusion during editing can be prevented and reliable editing can be realized.

The above-mentioned setting action does not necessarily have to be performed during the entire period of the ready state. Just do it once before or after the state transfer.

The aforementioned phase comparator 7 is not limited to the configuration in Fig. 3, if the preset function of the preset initial value NP is added, and the setting function of the action center value NC with a high priority order of setting is added, then the NP, The preset value of NC switches the AND gate circuit 10 .

Also, it is possible to change the configuration of the preset function of the D.P.C 11. The aforementioned presetting means: use a preset pulse to select and control the setting input and reset input of the 2-input counter, and the desired count value can be preset as the initial value; It is also possible to perform the same preset when one of the inputs has no condition to control (set or reset) during the control period. Of course, various combinations of these methods are also possible.

Claims (2)

1, the pilot signal of recording picture tracking, and with regeneration pilot signal carry out in the magnetic recorder/reproducer of automatic tracking Control, at recording status, in the phase comparator that produces reference signal, according to the rotation detecting signal with capstan motor is the phase error signal that comparison signal obtains, and tape is carried out constant speed control; In reproduced state, the resulting tracking error signal of tracking error according to detecting rotating magnetic head carries out tracking Control; In the standby condition of assemble editing,, carry out tracking Control according to aforementioned tracking error signal; After recording status shifts, according to aforementioned phase error signal, tape is carried out constant speed control, meanwhile, in aforesaid standby condition, according to aforementioned rotation detecting signal, the action center value of aforementioned phase comparator set in the phase bit comparison; After shifting to aforementioned recording status, remove aforementioned set action, perhaps before or after shifting, aforesaid state carries out once above-mentioned set action at least.The present invention is exactly the editing servo method of above-mentioned feature.

2, the editing servo method of the 1st record of patent request scope has following feature: advance counter with 2 and constitute phase comparator, advance counter to aforementioned 2 and give the count value of putting in corresponding phase action center value relatively, carry out aforementioned set action again.

Images