KR920008935B1 - Indexing circuit and method - Google Patents

Abstract

The method is for searching the index quickly to find out the reproduction start point. The circuit comprises a microprocessor (1) providing the drive signal for an AFT control IC (2), a recording/reproducing amp. (3), a multiplier (20) multiplying the AFT signal, a low bandpass filter (21) detecting the multiplied AFT signal from the reproduced AFT one, a rectifier (22) rectifying the peak value of the multiplied AFT signal, and a comparator (23) comparing the rectified output to the reference voltage, and applying the compared output to the microprocessor.

Description

8mm VTR Index Search Circuit and Method

1 is a circuit diagram of one embodiment of the present invention.

2 is an operation chart when the mark switch is pressed according to the present invention.

3 is a flowchart of the operation when the index switch is pressed according to the present invention.

4 is a flowchart of the operation of the index search of the present invention.

* Explanation of symbols for the main parts of the drawings

1: Micom 2: ATF Control IC

3: recording and playback amplifier 4: splitter

20: multiplier 21: band pass filter

22: peak value detector 23: comparator

The present invention relates to an index search circuit and a method of an 8mm VTR. The present invention can be applied to an 8mm VTR integrated camera or a video camera to quickly find and play a desired playback start point.

Even with current 1 / 2-inch home VTRs and video cameras, there is a Video Serach System (VISS) function to quickly find the desired program starting point, but the 8mm VTR did not apply the VISS function. The reason for this is that video signals are recorded on 1 / 2-inch VTR tapes and 8-mm VTR tapes are different from each other. Audio signals, video signals, and control signals are recorded on the 1 / 2-inch VTR tape at fixed positions. The 8mm VTR tape is recorded with a mixture of audio signal, video signal, and ATF (Auto Track Finding) signal which serves as a control signal.

In other words, the VISS applied to the 1 / 2-inch VTR allows the control signal recorded at the desired playback start point to be recorded with a different duty ratio than the control signal in the general case, and then the point where the control signal's duty ratio is recorded differently during playback. By finding and playing from that point, I could quickly find the desired playback point, but since the 8mm VTR had no control signal, I could not use the VISS function used for the 1 / 2-inch VTR. Therefore, it was inconvenient to find the desired starting point in the 8mm VTR because it is not possible to construct an inductance search system that finds and plays the desired starting point at high speed.

In view of the above, an object of the present invention is to provide an index search circuit and a method of an 8mm VTR to perform an index search function to find a desired playback starting point even in an 8mm VTR. In the 8mm VTR in which the ATF signal is mixed with the video signal and the audio signal in the recording and playback amplifier, and then recorded on the tape, the recorded signal is detected and the video and audio signal processing amplified by the recording and playback amplifier is performed. When the desired spot is selected, the multiplier is operated to multiply the ATF signal output from the ATF control IC, and to record on the tape through the recording / playback amplifier, and the signal detected during reproduction is a bandpass filter for passing the multiplied ATF signal. Determination of ATF signal multiplied by comparator by detecting peak value and inputting to comparator It is configured to input control signals to the microcomputer.

In addition, the microcomputer of the present invention accepts the selection input of the index search point only during recording, operates the multiplier, and when the index search point is found, determines whether to play from the set index search point and then performs the FF or REW operation. When the index search selection point is counted and the desired index search selection point is counted, the playback operation is performed from that point on.

If you select the index search point in 8mm VTR, the multiplier operates to multiply and record the ATF signal, and if you select the number of the index search point you want to play, the ATF signal multiplied by the microcomputer will be activated. The present invention, which counts each time it appears and plays back from a desired index search point, will be described in detail with reference to the accompanying drawings.

1 is an exemplary circuit diagram of the present invention. The present invention relates to an ATF control IC 2 that is operated by a drive signal of a microcomputer 1 and generates an ATF signal, and an ATf signal generated by the ATF control IC 2. In an 8mm VTR configured with a recording and playback amplifier 3 which is combined with a video and audio signal to record and reproduce on a tape, the ATF signal generated by the ATF control IC 2 is multiplied and is driven by the drive signal of the microcomputer 1. By using the multiplier 20, the low pass filter 5 for removing the high frequency of the ATF signal multiplied by the multiplier 20 and applying it to the recording and playback amplifier 3, and the recording and playback amplifier 3 A band pass filter 21 for detecting only the multiplied ATF signal among the reproduced ATF signals, a peak value detector 22 for passing the band pass filter 21 and detecting a peak of the multiplied ATF signal, and the peak value detection By comparing the detection output of the unit 22 with the reference voltage Connection configuration of the comparator 23 is applied to the Is baedoen ATF signal is detected to the microcomputer (1) to the to.

Here, the microcomputer (1) is a multiplier (20) for a predetermined time to the terminal (③) when the b switch mark (SW1) for outputting the drive signal of the ATF control IC (2) from the terminals (④) (⑤) during the recording operation is pressed A search signal for outputting the drive signal for operating the control unit is selected and an index search point to be reproduced according to the index switch SW2 power is selected, and the index search point is recognized by checking the output of the comparator 23 with the terminal ⑥.

The ATF control IC 2 receives an oscillation output of about 5.9 MHz from the oscillator 11 in the divider 4 according to the drive signal of the microcomputer 1, and thus 1/58, 1/50, 1/30, 1 /. After dividing by 40, an ATF signal (102.54, 118.95, 165.21, 148.69 MHz) is generated. The recording and playback amplifier 3 includes a mixing section 6 for mixing ATF signals, video and audio signals, an amplifying section 7 for amplifying the mixed signals of the mixing section 6 and recording them in the head 8; And an amplifying section 9 for amplifying and outputting the signal reproduced by the head 8.

In the present invention looks at the blocking method for recording a general ATF signal.

The microcomputer 1 recognizes the recording key not shown and outputs a drive signal to the terminals ④ and ⑤ to operate the ATF control IC 2 to operate the distributor 4 in the ATF control IC 2. To generate an ATF signal that acts as a control signal.

At this time, the ATF control IC 2 divides the oscillation output of about 5.9 MHz into 1/58, 1/50, 1/36, and 1/40 in the divider 4, thereby providing an ATF of 102.54KHz118.95Khz, 165.21KHz, 148.69KHz. Generate a signal. The ATF signal generated by the ATF control IC 2 is recorded by the head 8 through the amplifying unit 7 mixed with the video signal and the audio signal by the mixing unit 6 applied to the recording / reproducing amplifier 3. Lose.

Here, the low pass filter 5 sets its pass frequency to 350KHz, and the general ATF signal is applied to the recording / playback amplifier 3 without being affected, and the multiplier 20 does not send a drive signal from the microcomputer 1. It will not work.

However, when the user presses the mark switch SW1 to select the index search point to be played, the microcomputer 1 outputs the driving signal to the terminal ③ for a predetermined time (2-3 seconds), thereby increasing the multiplier 20 ) Only for a certain time. At this time, the microcomputer 1 operates the multiplier 20 at the time of inputting the mark switch SW1 for a predetermined time only when the mark switch SW1 is input while disregarding the input of the mark switch SW1, as in the flowchart of FIG. 2.

When the mark switch SW1 is pressed to operate the multiplier 20 in the microcomputer 1 during the recording operation, the multiplier 20 doubles the ATF signal output from the ATF control IC 2 (205.08, 118.95, 165.21, 148.69 kHz), passed through the low pass filter 5, and then applied to the recording / playback amplifier 3 to record the ATF signal multiplied by the multiplier 20 for a predetermined time. At this time, the low pass filter 5 sets the pass frequency to 350 KHz so that only the ATF signal multiplied by 2 times the ATF signal is applied to the recording / reproducing amplifier 3 and no higher frequency frequencies generated in the frequency mixing process are passed.

Therefore, if the user presses the mark switch (SW1) during recording, the ATF signal multiplied for a certain time is automatically recorded on the tape, and the pressing of the mark switch (SW1) can be executed several times on one tape. have.

The above is a description of the operation at the time of recording, and at the time of reproduction, the signal picked up from the head 8 is applied to the amplifier 9 of the recording / reproducing amplifier 3, amplified, and then a video signal not shown through the buffer 10. It is applied to the processing stage and the audio signal processing stage to perform signal processing, and the output signal of the buffer 10 is applied to the peak value detector 22 through the band pass filter 21 which passes only the multiplied ATF signal, and then the peak value. It is detected and converted to DC level. At this time, the pass frequency of the band pass filter 21 is set to 200-350KHz so that only the multiplied ATF signal is applied to the peak value detector 22, and the peak value detector 22 detects the peak value of the multiplied AFT signal to a DC level. Change.

The peak detector 22 and the output are applied to the non-inverting terminal (+) of the comparator 23 and compared with the ground potential of the inverting terminal (-), and the output of the comparator 23 is the terminal (6) of the microcomputer 1. ) Is recognized as a control signal. At this time, only when the multiplied ATF signal is not recorded on the tape, the peak detector 22 converts the multiplied ATF signal to the DC level, so that the comparator 23 makes a high level only at the point where the multiplied ATF signal is recorded. When the multiplied ATF signal is not recorded, the comparator 23 outputs a low level. Therefore, the microcomputer 1 checks the input of the terminal ⑥ and recognizes that there is a multiplied ATF signal (the point where the index search is selected) whenever the high level is applied.

That is, in the microcomputer 1, when the mark switch SW1 is pressed, the multiplied ATF signal is recorded on the tape for a predetermined time, and the index switch SW2 is pressed to select the number of times the multiplied ATF signal to be played back from the display. The ATF signal multiplied on the tape can be recorded many times, so the user must press the index switch (SW2) to select the playback start point. When the FF switch (SW3) or REW switch (SW4) is pressed, the index switch on the microcomputer (1) When (SW2) is not pressed, normal FF or REW operation is performed. When index switch (SW2) is pressed, FF performs REW operation. Terminal (⑥) input (High level when playing multiplication of ATF signal) When the ATF signal multiplied by the number of times selected by the index switch SW2 is stopped, the FF or REW operation is stopped and the playback operation is performed.

Such an index search method of the present invention will be described with the flowcharts of FIGS. 2 to 4.

Performs the process of recording the multiplication money ATF signal to the index search point by checking the mark switch press only during the recording operation, and setting the desired search point among the index search points to counter A by recognizing the index switch press. In addition, the process of checking that the multiplied ATF signal is detected by the counter B during the FF and REW operation is performed, and the regeneration operation is performed when the count values of the counter A and the counter B are the same.

First, FIG. 2 is a flow chart when the mark switch SW1 of the present invention is pressed to check the pressing of the mark switch SW1, and if the mark switch SW1 is pressed, it is being recorded and the record is made when the mark switch SW1 is pressed. When the microcomputer 1 is in operation, the driving signal is output to the terminal ③ for a predetermined time, and the multiplier 20 is operated to press the mark swikey SW1 during recording so that the ATF signal multiplied on the tape is recorded for a predetermined time.

At this time, even if the mark switch SW1 is pressed, the multiplier 20 is not operated unless the multiplier 20 is being recorded, and thus, the multiplied ATF signal is not recorded on the tape. ), But only when recording.

In other words, when the mark switch SW1 is pressed at each point where playback is desired by the search function, the multiplied ATF signal is recorded on the tape, and the multiplied ATF signal may be recorded on one tape.

In this way, the user sets the multiplied ATF signal that can find the playback start point by the index search function by pressing the mark switch (SW1) when recording on the tape, and the desired playback start point has a tape in which the multiplied ATF signal is recorded several times. In order to find the, press the index switch (SW2) to set the number of times the reproduction operation from when the multiplied ATF signal is detected.

That is, for example, when the tape having recorded ATF signals multiplied in five places is desired and playback is desired from the point where the third collected ATF signal is recorded from the beginning of the tape, the index switch SW2 must be pressed three times. However, if the tape is wound between the second multiplied ATF signal and the point where the third multiplied ATF signal is recorded, press the index switch (SW2) once to resume playback from the point where the third multiplied ATF signal is recorded. You can give it. Thus, the operation of selecting the point where the multiplied ATF signal desired to be reproduced by pressing the index switch SW2 will be described based on the flowchart of FIG.

When the index switch SW2 is pressed, the counter A which counts the index switch SW2 is operated, counts that the index switch SW2 is pressed once, operates by setting the internal timer, and then counts a predetermined time within a predetermined time. It is again checked whether the index switch SW2 is pressed.

If the index switch SW2 is pressed again within a certain time, the internal timer is cleared, and then the counter A that counts the index switch SW2 is increased once, and the number of times the index switch SW2 is pressed repeatedly is repeated several times. It is checked whether the index switch SW2 is pressed. If the index switch SW2 is not pressed until a certain time elapses, the index flag is set to 1 and the operation ends.

That is, the microcomputer 1 sets the index flag to 1 after counting how many times the index switch SW2 is pressed within a predetermined time by operating an internal timer. At this time, the index switch SW2 is pressed from the current tape position. When the multiplied ATF signal is detected, the playback operation is selected.

In this way, press the index switch (SW2) to set how many times the ATF signal is to be played back, and then press the FF switch (SW3) or the REW switch (SW4) to search for the set playback position. We explain according to chart.

When the FF switch (SW3) or the REW switch (SW4) is pressed, the microcomputer (1) checks the index flag set to 1 when the index switch (SW2) is pressed. If the index flag is not set to 1, the index switch (SW2) is turned on. Since it is not pressed, it performs normal FF or REW operation.

However, if the index flag is set to 1 when the FF switch (SW3) or the REW switch (SW4) is pressed, the index switch (SW2) is pressed. At this time, whether the multiplied ATF signal is detected by performing the FF or REW operation. Each time a check is made, the multiplied ATF signal is counted by the counter B. At this time, the multiplied ATF signal is compared with the value of the counter A, which counts the number of detection times, because the index switch SW2 is pressed.

That is, when the FF switch (SW2) or the REW switch (SW4) is pressed, the index flag is set to 1, and FF or REW operation is performed to detect the multiplied ATF signal and to the counter B whenever the multiplied ATF signal is detected. After counting, the value of Counter B and Counter A coincide with each other. At this time, if the values of Counter A and Counter B coincide, the values of Counter A and Counter B are cleared to 0, and the index flag is cleared to 0, and the playback operation is performed from that point.

As described above, when the ATF signal multiplied by the number of times set by the index switch SW2 while performing the FF or REW operation is detected, the operation of stopping the FF or REW operation and performing the regeneration operation will be described.

For example, if you want to perform the playback operation when the ATF signal multiplied by the third position of the current tape is detected, first press the index switch (SW2) three times and count the index switch (SW2) three times with the counter A. After pressing the FF switch (SW3), the FF operation is performed. Whenever the multiplied ATF signal is hidden during the FF operation, the counter counts toward Counter B and compares the Counter A value with the Counter B value.

Therefore, when the third multiplied ATF signal is detected during FF operation, the values of counter A and counter B coincide with each other. Thus, when the values of counter A and counter B coincide, FF operation stops and playback operation is performed. You can watch the playback screen quickly.

For example, if you want to perform the playback operation when the ATF signal multiplied upside down from the current tape position is detected, first press the index switch (SW2) to count 2 with the counter A, and then press the REW switch (SW4). If the AW signal is detected during the execution of the REW operation, the counter counts toward the counter B and compares the counter A value with the counter B value.

Therefore, when the 23rd multiplied ATF signal is detected during the REW operation, the values of counter A and counter B become equal, and from this time, the REW operation is stopped and the playback operation is performed so that the user can find the desired point quickly and watch the playback screen. do.

As described above, the present invention records the ATF signal collected at the point where playback is desired by the index search function in the 8mm VTR, and selects the number of times when the multiplied ATF signal is detected to perform the playback operation. If the REW operation is performed, the multiplied ATF signal is detected to perform the regeneration operation from when the selected number of times is detected, and thus the regeneration operation can be performed by finding a desired point in 8 mm VTR as soon as possible.

Claims (3)

ATF control IC 2, which is operated by a microcomputer 1 driving signal and generates an ATF signal, and a recording which synthesizes ATF signals generated by the ATF control IC 2 with video and audio signals to record and reproduce them on a tape. In an 8 mm VTR configured with a reproducing amplifier 3, a multiplier 20 which multiplies the ATF signal generated by the ATF control IC 2 and is operated by a drive signal of the microcomputer 1, and the multiplier 20 A low pass filter 5 for removing the high frequency of the multiplied ATF signal and applying it to the recording / reproducing amplifier 3, and a bandpass filter 21 for detecting only the multiplied ATF signal among the ATF signals reproduced from the recording / reproducing amplifier 3. ), And the peak value detector 22 for detecting the peak value of the multiplied ATF signal through the band pass filter 21 and the detected output of the peak value detector 22 with the reference voltage Is applied to the microcomputer 1 A comparator (23) index book worth circuit of the 8mm VTR, characterized in that that the connection configuration. 2. The microcomputer (1) according to claim 1, wherein the microcomputer (1) is configured to operate the multiplier (20) which doubles the ATF signal by recognizing the pressing of the mark switch (SW1) at the time of recording, and the number of pressing of the index switch (SW2) and the comparator An index search circuit of 8 mm VTRs configured to compare the number of times the ATF signal multiplied in 23 is detected. The process of recording the ATF signal multiplied to the index search point by checking the mark switch teasing only during the recording operation, and setting the desired search point among the index search points to counter A by recognizing the index switch pressed. And performing a process of checking, by counter B, that the multiplied ATF signal is detected during the FF and REW operations, and executing a regeneration operation when the count values of the counter A and the counter B are equal to each other. 8mm VTR Index Search Method

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