JP2629322B2 - Magnetic recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic recording / reproducing apparatus having a still reproducing function.

2. Description of the Related Art FIG. 7 is a schematic diagram of a recording format of a current video cassette recorder of the VHS system. 131 is an audio track, 134 is a video track, a signal for one field of a video signal is recorded on one recording track, and adjacent tracks are alternately recorded by L heads and R heads having different azimuth angles. Further, T1 represents 1/30 seconds of the time of one frame of the video signal, and T2 represents 1/60 seconds of the time of one field. Reference numeral 135 denotes a control signal (hereinafter, referred to as a CTL pulse signal) for controlling the running of the magnetic tape, which is generated once every time the magnetic tape advances by two tracks, that is, once every T1.
Has been recorded times. 133 indicates the running direction of the magnetic tape, and 132 indicates the recording direction of the rotary head.

In the apparatus already proposed in the magnetic tape running control means at the time of transition from the normal reproduction to the still reproduction of the recorded signal of the magnetic tape recorded in the recording format, the running of the magnetic tape is performed based on the CTL pulse signal. After the capstan motor, which is the driving device for the motor, is stopped, if the one-field frame advance operation is performed, the one-field frame advance operation is performed four times. If the one-frame frame advance operation is performed, the one-frame frame advance operation is performed. After performing the feeding operation once, the capstan motor is stopped to obtain a stable still reproduced image.
Hereinafter, the control method already implemented using a microprocessor as the control means will be described for the case of having a one-frame frame forwarding operation and the case of having a one-frame frame forwarding operation.

(1) In the case of conventional one-field frame feed operation FIG. 8 shows a timing chart of this method. The configuration will be described for convenience using a part of FIG. 1 which is an embodiment of the present invention. Here, only the process of shifting from normal reproduction to still reproduction in the case of having the one-field frame feed operation will be described.

First, the capture control device 107 in the microprocessor 100 stores the following signal arrival times in the corresponding registers using the time base counter 111 that counts the reference clock signal p. That is,
The count data at the time of arrival of the CTL pulse signal d, which is the output of the amplifier 104 of the CTL pulse signal j, is stored in the CTL register 108 as the CTL pulse signal arrival time, and the arrival time of the FG pulse signal k, which is the output of the amplifier 105 of the FG signal j. FG register 109
Next, the arrival time of the delay completion pulse signal q output from the delay device 106 having the mono-multi configuration is stored in the delay register 110. Also, when each signal arrives, a corresponding arrival flag is generated as follows to enable detection by software of the microprocessor. That is, when the CTL pulse signal d arrives, the CTL arrival flag 1 is generated, when the FG pulse signal k arrives, the FG arrival flag m is generated, and when the delay completion pulse signal q arrives, the delay completion flag n is generated.
Here, as the operation of the delay device 106, the charging start operation of the mono-multi circuit composed of the external circuit is started with the delay start signal e output from the capstan processing device 101 as a trigger. A configuration that outputs the delay completion pulse signal q is used. Also,
In this configuration, the mono-multi operation time can be obtained as the tracking time as described below. That is,
The respective times of the start of charging and the completion of charging of the mono-multi circuit are determined using the count data of the time base counter, the time difference between them is calculated, and the time difference is detected as a tracking time.

Next, the transition operation timing from the normal reproduction to the still reproduction in the case of having the one-field frame feed operation will be described with reference to the timing chart of FIG.

First, when the transition to the still reproduction is started at the timing of t0, when the capstan processing device 101 detects the CTL arrival flag 1 obtained by the arrival of the CTL pulse signal d at the timing of t1, the RAM device shown in FIG. The RAM 1 (referred to as FG counter 1) in 113 is cleared, and the preset data N1 is set in the RAM 2 (referred to as FG counter 2) as an initial value of the FG counter 2 at the time of transition to still playback, and the FG counter is set. The FG counting operation is started by using 1 and 2. Here, the FG count operation means the FG arrival flag m obtained by the arrival of the FG pulse signal k generated by the rotation of the capstan motor in the capstan processing device 101.
Is detected, the values of the FG counter 1 and the FG counter 2 are each incremented by one, and
The FG arrival flag m is reset so that the next FG pulse signal k can be detected by software. Next, after detecting the CTL pulse signal d, the capstan processing device 101 outputs the capstan rotation direction command signal c of FIG.
The brake stop control of the capstan motor is started. Further, at the timing of t2, the level of the capstan current limit signal b is switched from H to middle at the timing of t2 to reduce the braking force of the capstan motor and to detect the stop of the capstan motor. Then, the cycle detection of the FG pulse signal k is started, and when the cycle of the FG pulse signal k exceeds predetermined cycle data at the timing of t3, it is determined that the stop of the capstan motor is completed. The limit signal b and the capstan rotation direction command signal c are set to Low.
By turning the output on, the current supply to the capstan motor is stopped. Here, the operation from the timing t1 to the timing t3 is referred to as brake stop control of the capstan motor. Further, the counting operation of the FG counters 1 and 2 is stopped at the timing of the t3, and the FG counting operation while the capstan motor is stopped is prohibited.

At this point, the capstan motor has stopped and is in the still reproduction state. However, the rotational speed of the capstan motor immediately before the brake stop control of the capstan motor has not been particularly accurately determined. Therefore, the variation in the stop position of the tape becomes large, and the still image is not stable. Therefore, the still image state is stabilized in the same manner as the still image in the normal frame feeding operation by performing several frame feeding operations as described below.

In the following, a description will be given of a process in which the transition from the normal reproduction to the still reproduction is completed by further executing the one-field frame feed operation four times from the state where the capstan motor is first stopped in the transition to the still reproduction.

First, before the capstan motor is activated in the frame feed operation, the tracking time used to determine the brake stop control timing of the current capstan motor is calculated in advance.

First, the capstan processing device 101 outputs the delay start signal e to the delay device 106 at the timing of t4 to start the charging operation of the mono-multi circuit, and counts the count data of the time base counter 111 of the charging operation start timing. Into the RAM 4 in the RAM device 113 in the delay start time Tds
Then, when the delay completion pulse signal q is generated at the time of completion of charging, the count data of the time base counter 111 at the time of completion of charging is stored in the delay register 110 by the capture control device 107 as the delay completion time Tde. At the same time, the delay completion flag n is generated. And, the capstan processing device 10
In 1, the delay start time Tde and the delay completion Tds
The result obtained by calculating the time difference (Tde−Tds) from the above is called a tracking time Td, and the operation of calculating the tracking time Td is called a tracking time calculation operation.

Here, the tracking time Td refers to a time difference from the input timing of the CTL pulse signal d to the brake start timing of the capstan motor in the frame feed operation executed in the processing after t4. Since the CTL pulse signal can be obtained only once in every two frame forwarding operations, the CTL pulse signal d
Therefore, the input movement timing of the tape cannot be detected, and therefore, the amount of movement of the tape due to the rotation of the capstan motor is measured by the count number of the FG pulse signal k, and the tracking is performed using the target rotation speed of the capstan motor in the frame feed operation. The time Td is converted into the count number R of the FG pulse k, and the count number R is finally defined and used as the tracking number N2. The operation of calculating the tracking number N2 is called a tracking number calculation operation. In the frame feed operation, the input CTL pulse signal is compared with the count number R of the FG pulse signal k generated by the actual rotation of the capstan motor, and the braking start timing of the capstan motor is determined based on the result. Is determined.

Next, in the capstan processing device 101, at the timing of t5 in FIG. 8, a capstan activation command signal always delayed by a certain time from the rising edge of the head switching signal indicating the rotational phase of the head from the system processing device 113 in FIG. When h is input, it is determined that the frame feed operation is in the start mode, and the capstan current limit signal b is output as high to the capstan driving device 102, so that the capstan motor is accelerated in the direction in which the capstan motor is accelerated. A current signal a is output. This operation is called a capstan motor acceleration control operation.

Next, from time t6 to time t10, processing is performed during frame advance operation of a field in which the CTL pulse signal d is not generated. When the transient state of the FG pulse signal k caused by the activation of the capstan motor at the timing of t6 is completed, the capture is performed. The stun processing device 101 restarts the FG counting operation using the FG counters 1 and 2, and when the data of the FG counter 2 reaches the reference pulse number N3 corresponding to one field at the timing of t7, the FG counter 2 is cleared, which means creation of a pseudo CTL pulse in the frame-by-frame advance operation of a field in which the CTL pulse signal d cannot be detected, which is a conventional method.

Subsequently, when the count data of the FG counter 1 reaches the tracking number N2 at the timing of t8, the brake stop control is performed on the capstan motor,
At the timing of t10, the capstan motor stops, and the counting operation of the FG counters 1 and 2 stops. Next, at the timing of t11, the tracking time calculation operation as in the process at the timing of the t4, and
The tracking number calculation operation is performed to newly calculate a tracking time Td and a tracking number N2. That is, the tracking N2 is calculated before the activation of the capstan motor in each frame feed operation. This is one method for changing the external number of the delay device 106 during the frame feed operation so that the tracking number N2 can be changed so that the brake stop control timing of the capstan motor can be changed.

Next, t12 to t17 are processes during the frame advance operation of the field in which the actual CTL pulse signal d can be detected.
At the timing of the above, the acceleration control operation of the capstan motor is started again, at the timing of t13, the FG counting operation is started, and at the timing of t14, the capstan processing device 101 clears the FG counter 1 when detecting the CTL flag l. When the count data of the FG counter 2 reaches the tracking number N2 at the timing of t15, the brake stop control of the capstan motor is performed, and the capstan motor stops at the timing of t17. Hereafter,
The operation from the timing t4 to the timing t17 is repeated once more, thereby completing the transition to the still reproduction at the timing t18. That is, once the capstan motor is stopped in the transition to still playback,
Further, by performing four one-field frame feeding operations, variations in the tape stop position can be absorbed, and a stable still reproduced image can be obtained.

(2) Conventional one-frame frame feed operation FIG. 9 shows a timing chart of this method. The configuration will be described for convenience using a part of FIG. 1 which is an embodiment of the present invention. Here, only the process of shifting from the normal reproduction to the still reproduction in the case where the one-frame frame feed operation is performed will be described.

The concept of the control method in the one-frame frame feed operation is the same as the above-described one-field frame feed operation and the acceleration control and the brake control of the capstan motor, and the difference is in the method of generating the brake control start timing of the capstan motor. The FG count operation and the tracking number calculation operation are not performed, and the brake stop control of the capstan motor is started after the lapse of the tracking time Td from the arrival time of the CTL pulse signal d using the tracking time Td. It is characterized by doing.

The operation from timing t30 to timing t33 in FIG. 9 is the same as the operation from timing t0 to t3 in FIG. Next, when the capstan processing device 101 detects the CTL flag 1 at the timing of t34, it counts the count data of the time base counter 111 at this time to the CTL arrival time Td.
Detect as c. Subsequently, at time t38, a time difference (Tnow-Tdc) between the present count data Tnow of the time base counter 111 and the CTL arrival time Tdc is obtained as a CTL pulse signal arrival elapsed time Tdk, and the CTL pulse signal arrival elapsed time Tdk is calculated. When the tracking time Td is reached, brake stop control of the capstan motor is started, and the capstan motor stops at the timing of t40. Thereafter, the operation from the timing t34 to the timing t40 is repeated three times, and the transition to the still reproduction is completed at the timing t41. That is, once the capstan motor is stopped once in the transition to the still reproduction,
By performing the one-frame frame feed operation of each time, variations in the stop position of the tape can be absorbed, and a stable still reproduced image can be obtained.

However, in the conventional configuration, when shifting to the still reproduction, the brake stop control of the capstan motor is performed regardless of the speed of the capstan motor when the first CTL pulse signal arrives. In this case, since the magnetic tape is stopped once, the stop position of the magnetic tape greatly varies, and the stop accuracy cannot be obtained. Therefore, the positional relationship between the track of the rotating head and the track on the magnetic tape is not uniquely determined, and the still reproduced image obtained in that state becomes unstable. Therefore, according to the conventional method, once the capstan motor is stopped by performing the brake stop control of the capstan motor in the transition to the still reproduction, four more one-field frame feed operations or one frame frame feed operation are further performed. In this method, a good still image was obtained.However, this method requires a long time to complete the transition to still playback, and the quality of the image during the transition is not limited by frame fluctuation due to the frame advance operation. There is a problem that it is not good. The reason why the frame feed operation is performed four times is that the rotation speed of the capstan motor at the timing when the brake stop control of the first capstan motor is performed at the time of transition to the still playback is the target rotation of the frame feed operation. When the tape is stopped by controlling the brake stop of the capstan motor while the speed is not sufficiently reduced (60% to 70% of the speed during normal playback), the tape tension may be reduced. is there. Therefore, the tape tension is made normal by the frame feeding operation about four times from the above state, and a stable still image is obtained.

The present invention shortens the transition time to the still reproduction by performing the brake stop control of the capstan motor only once without performing the frame feed operation four times at the time of the transition to the still reproduction. The transition to the still reproduction is stably completed.

Means for Solving the Problems According to the present invention, at the time of transition to still reproduction, the control speed of the capstan motor is changed from normal reproduction to one-field frame advance operation or constant speed in one frame frame advance operation as in the conventional method. The start timing of the brake stop control of the capstan motor is generated while controlling to the target speed in the control period, but as a new process, the actual speed of the capstan motor is always unified before the brake stop control of the capstan motor is executed. Means for determining whether or not the actual rotation speed of the capstan motor has reached the target speed, and generating a constant speed control completion flag when the rotation speed has reached the target speed. As a constant speed control completion flag generator 114.

Further, when a one-field frame feed operation is performed as a delay amount for determining the brake stop control start timing of the capstan motor based on the CTL pulse signal input timing, the delay amount used in the normal one-field frame feed operation is used. The same number as the tracking number N2 is detected before the brake stop control of the capstan motor is performed at the time of transition to the still playback, and is used in the normal one-frame frame feed operation when the one-frame frame feed operation is performed. The same time as the tracking time Td is detected before executing the brake stop control of the capstan motor at the time of transition to the still reproduction, and further, after that, the occurrence of the constant speed control completion flag is detected. A pulse signal is detected, and only the calculated tracking number N2 or tracking time Td A second means for generating a start timing of the brake stop control of the capstan motor at the time when the time has passed is added. Therefore, the brake stop control of the capstan motor at the time of transition to the still reproduction and the capping in the normal frame feed operation are performed. This makes it possible to make the brake stop control condition of the stun motor the same.

Function The present invention provides a method for controlling the actual rotation speed of the capstan motor and the brake stop control of the capstan motor determined by the tracking number or the tracking time based on the CTL pulse signal at the time of transition to still reproduction. By applying the same start speed as the same rotation speed and the same number of tracking or the same tracking time in the normal frame feed operation, the brake stop control of the capstan motor is performed only once so that the tape stop accuracy is obtained. Can be made the same as during normal frame advance, eliminating the need to perform four frame advance operations, shortening the transition time to still playback, suppressing screen shaking, and quickly maintaining screen quality during transition. This completes the transition to still playback.

Embodiment Hereinafter, a configuration of an embodiment of the present invention will be described with reference to the drawings. Since a part of the configuration of this embodiment has already been described in the conventional example, here, the constant speed control completion flag generator 11 added as the first means which is a feature of this embodiment is described.
4 and the second means added to the capstan processing apparatus 101 of FIG. 1 will be described.

Hereinafter, the first means will be described with reference to the flowchart of FIG. The first means can employ the same method in the case of having the one-field frame advance operation and in the case of having the one-frame frame advance operation.

First, the branch 20 in FIG. 2 determines whether or not the FG arrival flag m generated by the arrival of the FG pulse signal k is set in the capstan processing device 101 in FIG. 1, and the result is true. If so, the FG arrival flag m is reset in the processing block 21 and in preparation for the next arrival of the FG pulse signal k, it is determined in the branch 22 whether or not the mode is a transition mode from normal reproduction to still reproduction, and the result is true. If so, the process proceeds to a processing block 23, in which the target rotation speed of the capstan motor is set to the same value as the target rotation speed in the constant speed control period of the one-field frame feed operation or the one-frame frame feed operation, and the constant speed error processing (Error calculation). On the other hand, if the result of the branch 22 is false, in the processing block 33, the target rotation speed is set to the speed in the normal reproduction, and the speed error processing (error calculation) is performed.

Next, it is determined whether the speed error has reached the control range in the branch 24, and if the result is true, the speed error is determined to be valid in the processing block 25 as in the conventional method. On the other hand, if the result is false, it is determined that the value is out of the control range, and the maximum value or the minimum value is output in the processing block 31.

Subsequent processing blocks 26, 27, 28, 29, and 32 are newly added processing and are executed by software in the constant speed control completion flag generation device 114. Here, in order to determine that the actual rotation speed of the capstan motor during the transition to still playback has reached the control range of the target speed, it is detected that the speed error has continuously reached the control range. Take the method of doing. Therefore, first, in the branch 26, the constant speed control counting RAM 8 (hereinafter, referred to as the RAM 8) in the RAM device 113.
It is called a constant speed control counter. ) Is determined as to whether or not the count data has reached a constant value M. If the result is true, it is determined that the actual rotation speed of the capstan motor has reached the control range of the target rotation speed, In processing block 27, a constant speed control completion flag is generated and output as a constant speed control completion flag V to the capstan processing device,
Subsequently, in processing block 29, the constant speed control counter is cleared. On the other hand, if the result of the determination in the branch 26 is false, it cannot be determined that the actual rotation speed of the capstan motor has reached the control range of the target speed, and therefore the constant speed control counter After performing the process of incrementing the count data by one, the process is terminated and the next speed determination process is waited for. If the result of the determination in the branch 24 is false, the transition to still reproduction is not made, so that the constant speed control counter is cleared. In the processing block 30,
In order to calculate the speed control error as in the conventional method, the expected arrival time of the next FG pulse signal k is calculated.

Next, the tracking time calculation operation, the tracking number calculation operation, the tracking time Td, and the tracking number N2 described in the above-described conventional method will be described, including the flowcharts used in the following, and the codes used in the timing diagrams. I do.

First, regarding the tracking time calculation operation and the tracking time Td, the operation and the result by the delay device 106 for determining the brake start timing of the capstan motor based on the input timing of the CTL pulse signal d in the frame advance operation are described. The capstan processing device 101 outputs the delay start signal e to the delay device 106 to start the charging operation of the mono-multi circuit, and count data of the time base counter 111 of the charging operation start timing. In the RAM device 113
Stored in AM4 as the delay start time Tds, and subsequently, when the delay completion pulse signal q is generated at the time of completion of charging, the capture control device 107 causes the delay register 1
In 10, the count data of the time base counter 111 at the time of completion of the charging is stored as the delay completion time Tde, and the delay completion flag n is generated. Then, in the capstan processing device 101, the delay start time Tde
The result obtained by calculating the time difference (Tde−Tds) between the delay time and the delay completion time Tds is defined as tracking time Td, and the operation of calculating the tracking time Td is referred to as tracking time calculation operation. Also, tracking time
In the flowchart of FIG. 4 in which Td is used below, it is set as T1.

Next, regarding the tracking number calculation operation and the tracking number N2, the tracking time Td refers to a time difference from the input timing of the CTL pulse signal d in the frame feed operation to the brake start timing of the capstan motor. However, in the one-field frame feed operation, the CTL pulse signal is output once every two frame-feed operations.
The input timing of the CTL pulse signal d cannot be detected each time, and therefore, the amount of movement of the tape due to the rotation of the capstan motor is measured by the number of counts of the FG pulse signal k. The tracking time is calculated using the target rotation speed of the capstan motor.
Td is converted into the count number R of the FG pulse k, and the count number R is finally defined as a tracking number N2, and an operation of calculating the tracking number N2 is referred to as a tracking number calculation operation. In the frame feed operation, the input CTL pulse signal is compared with the count number R of the FG pulse signal k generated by the actual rotation of the capstan motor, and the braking start timing of the capstan motor is determined based on the result. Is determined. Further, the tracking number N2 is set to N11 in the flowchart of FIG. 3 used below, and set to N6 in the timing chart of FIG.

Next, the constant speed control completion flag obtained by the first means,
The generation of the start timing of the brake stop control of the capstan motor using the second means will be described for each of the case of having a one-frame frame feed operation and the case of having a one-frame frame feed operation.

(1) In the case of one-field frame advance operation FIG. 3 is a flowchart in which this means in the case of having one-field frame advance operation is realized by software.
The branch 40 is determined in the same manner as the branch 30 in FIG. 2. If the result is true, the branch 41 branches to the RAM 11 for the parameter value in the RAM device 113 (hereinafter referred to as the parameter value, in the transition to the still reproduction). It is determined whether the data of P1 is the control sequence of the capstan motor.) If the result is true, the processing blocks 42 and 43 newly added this time are executed. That is, in the processing block 42, the tracking time
Calculation of Td, the tracking number in processing block 43
The calculation of N2 (N11 in the flowchart of FIG. 3) is performed, and subsequently, in a processing block 44, the parameter value is set to P2. Here, since the parameter value is P1 in normal reproduction, the initial value of the parameter value is P1 when shifting to still reproduction,
41, processing block 42, processing block 43, processing block 44
Is executed promptly.

Subsequently, in the next software task processing, the result of the determination at the branch 41 and the branch 45 again passes through the branch 40, since the parameter value is P2,
The process proceeds to the newly added branch 46 to determine whether or not the constant speed control completion flag has been set. If the result is true, the FG counter 1
The FG counting operation is started by using the CTL pulse signal d to prepare for the condition when the CTL pulse signal d is missing. Next, at the branch 48, the C signal generated by the arrival of the actual CTL pulse signal d
It is determined whether or not the TL flag 1 has been set. If the result is true, the preset data N4 is set as the initial value of the FG counter 2 in the processing block 50 at the time of transition to the still reproduction in the processing block 50. Then, the FG counting operation using the FG counter 2 is started, and the next processing block 51
In, the parameter value is set to P3. Here, in the normal reproduction, the data of the FG counters 1 and 2 are cleared, and the FG counting operation is stopped.

Subsequently, when the next software task processing shown in FIG. 3 is executed, the processing shifts to the newly added branch 52 according to the parameter value, and the FG counter 2 sets N1.
It is determined whether or not 1 has been reached, and if the result is true, the process proceeds to a processing block 53, in which the brake stop control of the capstan motor is started, and the processing block newly added this time.
At 54, the constant speed control completion flag is reset, and then, at processing block 55, the parameter value is set to P4, and thereafter, the capstan motor is stopped to complete the transition to still reproduction. That is, in the transition to the still reproduction, the brake stop control of the capstan motor is set to one.
It is completed by performing only the times. The branch 48
Is false, in branch 49,
It is determined whether the value of the FG counter 1 has reached a reference count value N5 corresponding to two tracks, and if the result is true, the processing block 53, the processing block 54, and the processing block 55 are executed. By executing this, a stable transition to still reproduction is performed even when the CTL pulse signal is lost.

Next, the transition timing to the still reproduction will be described with reference to the timing chart of FIG. First, when the transition to the still reproduction is started at the timing of t50, when the value of the constant speed control counter in the constant speed control completion flag generator 114 reaches the constant value M, the actual rotation speed of the capstan motor is increased. Is determined to have sufficiently reached the target rotation speed in the normal frame feed operation, the constant speed control completion flag is set. Next, when the delay start signal e is output to the delay device 106 at the timing of t52, the tracking number is calculated in the same manner as in the conventional method. Here, the tracking number is set to N6. (N11 in the flowchart of FIG. 3)
Is equivalent to Then, when the calculation of the tracking number N6 is completed at the timing of t53, the parameter is set to P2. Next, when it is determined that the constant speed control completion flag is set at the timing of t54, the FG counting operation using the FG counter 1 is started to enable the determination of the lack of the CTL pulse signal d. Then, when the arrival of the CTL pulse signal is actually determined at the timing of t55, the preset data N4 is set as the initial value in the FG counter 2, the FG counting operation is started, and the parameter is set.
Set to P3. When the value of the FG counter 2 reaches the tracking number N6 at the timing of t56, the brake stop control of the capstan motor is started, and at the timing of t57, the capstan motor stops, and the transition to the still reproduction is completed. I do.

(2) In the case of one-frame frame advance operation FIG. 4 is a flowchart in which this means in the case of having one-frame frame advance operation is realized by software. The branch 60 is the same as the branch 30 in FIG. 2. If the result is true, the branch 61 determines whether the data of the parameter value is P1. In the added processing block 62, the tracking time Td (T1 in the flowchart of FIG. 4) is calculated, and subsequently, in the processing block 63, the parameter value is set to P2.

Subsequently, in the next software task process, the process again passes through the branch 60 and shifts to the newly added branch 65 according to the parameter value, and determines whether the constant speed control completion flag has been set, If the result is true, in the processing block 66, the CTL pulse signal d
It is determined whether or not the CTL flag 1 is set at the time of the arrival of the CTL pulse signal d. If the result is true, the processing shifts to a processing block 68 to store the arrival time of the CTL pulse signal d at the time of arrival. The value of the register 108 is stored in the RAM 6 in the RAM device 113.
Is stored as the CTL signal arrival time Tdc in the next processing block.
At 69, the parameter value is set to P3.

Subsequently, when the next software task processing shown in FIG. 4 is executed, the processing shifts to the newly added processing block 70 according to the parameter value, and the current count data (Tnow) of the time base counter 111 and the current The time difference (Tnow−Tdc) from the CTL pulse signal arrival time Tdc is determined as the CTL pulse signal arrival elapsed time Tdk (T2 in the flowchart of FIG. 3). Subsequently, in the newly added branch 71, It is determined whether the CTL pulse signal arrival elapsed time T2 has reached the tracking time T1, and if the result is true, the process shifts to the processing block 72 to start the brake stop control of the capstan motor. In the added processing block 73, the constant speed control completion flag is reset, and in the processing block 74, the parameter value is set to P4. It was stopped Nmota to complete the transition to still reproduction. That is,
The transition to the still reproduction is completed by performing the brake stop control of the capstan motor only once.
If the result of the determination in the branch 66 is false, then in the next branch 67, the RAM for the CTL missing counter in the RAM device 113 that is counted up at regular intervals.
It is determined whether or not the content of 13 has reached a constant value θ, and if the result is true, the processing block 72, processing block 73,
By executing the processing block 74, a stable transition to still reproduction is performed even when the CTL pulse signal is lost.

Next, transition timing to still reproduction will be described with reference to the timing chart of FIG. First, the operation up to t62 is the same as the operation up to t52 in FIG. When the delay start signal e is output to the delay device 106 at the timing of t62, the tracking time T1 is calculated similarly to the conventional method, and the parameter value is set to P2 at the timing of t63. Next, when it is determined that the constant speed control completion flag is set at the timing of t64, the counting operation using the CTL pulse signal missing counter is started to prepare for the lack of the CTL pulse signal d. Next, when the actual arrival of the CTL pulse signal d is determined at the timing of t65, the value of the CTL register 108 is changed to the CTL pulse signal arrival time T.
Stored as dc and set the parameter value to P4. At time t66, a time difference (Tnow-Tdc) between the present count data Tnow of the time base counter 11 and the CTL pulse signal arrival time Tdc is obtained as a CTL pulse signal arrival elapsed time T2, and the CTL pulse signal arrival time is calculated. When the time T2 reaches the tracking time T1,
By performing the brake stop control of the capstan motor,
At the timing of t67, the capstan motor stops and the transition to the still reproduction is completed.

As described above, according to the present invention, the first means and the second means can be realized without increasing the cost, and the transition to the still reproduction can be performed while maintaining the screen quality at the transition from the normal reproduction to the still reproduction. It is possible to shorten the time and improve the response to the transition to the still reproduction.

[Brief description of the drawings]

FIG. 1 is a block diagram of a magnetic recording / reproducing apparatus according to an embodiment of the present invention, FIGS. 2, 3, and 4 are flowcharts according to the embodiment of the present invention, and FIGS. FIG. 7 is a timing chart for explaining the operation in the drawing, FIG. 7 is a recording format diagram of the VHS system, and FIGS. 8 and 9 are timing charts for explaining the operation in the conventional apparatus. 100: microprocessor, 101: capstan processing device, 102: capstan driving device, 107: capture control device, 108: CTL register, 109: F
G register, 110 delay register, 111 time base counter, 112 system processing device, 113 RAM device, 114 regular control completion flag generation device.

Claims (1)

(57) [Claims] 1. A normal reproducing apparatus comprising a rotary head capable of recording and reproducing a video signal, wherein the control signal is controlled at the same speed as that for recording when reproducing a magnetic tape on which a control signal is recorded every two tracks, and a capstan. Still playback that stops the magnetic tape by controlling the brake stop of a capstan driving device that drives a motor, and, from the still playback to the capstan driving device, acceleration, constant speed, and braking stop. The apparatus is capable of performing a one-field frame feed operation for running the magnetic tape one track at a time or a one-frame frame feed operation for running two tracks at a time by performing intermittent running in which the magnetic tape is controlled at regular intervals. When transitioning from normal reproduction to still reproduction, first, there is a normal one-field frame advance operation. Is the same as that used in the one-frame frame feed operation, that is, the amount of delay until the start timing of the brake stop control with reference to the input timing of the control signal is determined by the delay device. The control is started so that the rotation speed of the capstan motor is the same as the target rotation speed during the constant speed control period in the one-field frame feed operation or the one frame frame feed operation. By a constant speed determination unit that determines whether the rotation speed has reached the target rotation speed, the control is continued until the result is obtained, and when the result is obtained, the first input that is thereafter input The tape is run by the rotation of the capstan motor by the amount of the delay time with reference to the input timing of the control signal of After, the magnetic recording and reproducing apparatus, characterized in that the by stopping the magnetic tape by performing only 4 times the brake stopping control to complete the transition to still reproduction.