JPH08221842A - Magnetic tape program-sharching device - Google Patents

Abstract

PURPOSE: To accurately detect a marker under high speed traveling by detecting a tape speed under searching in the device on a magnetic tape having a subtrack such as a DCC, etc., and accurately detecting a length of continuous recording of the subtrack. CONSTITUTION: During high speed traveling of a magnetic tape 104, an envelope of a regenerative signal is detected so that a recording format recorded on the subtrack is detected, and then an envelope period is detected. This envelope period and a reference burst recording period calculated by a reference calculating circuit 8 based on a tape speed detected by a tape speed detecting means 9 are compared by a comparing circuit 5, so as to obtain how many times of the detected envelope period is the reference burst period, and hence the marker under traveling is accurately discriminated to perform the program searching.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a subtrack for recording information for cueing on a magnetic tape such as a digital compact cassette tape recorder (hereinafter referred to as DCC), and the subtrack is provided in the subtrack. The present invention relates to a magnetic tape cueing device using a magnetic tape in which a recording shape is changed and recorded on a sub-track depending on the kind of information (hereinafter referred to as a marker) for cueing to be recorded.

[0002]

2. Description of the Related Art In recent years, a magnetic tape reproducing apparatus such as a DCC having a function of accurately locating a program recorded on a magnetic tape has been put into practical use.

A magnetic tape cueing device used in a DCC will be described below as an example of a conventional magnetic tape cueing device with reference to FIGS.

FIG. 3 is a block diagram of a conventional magnetic tape cueing device, FIG. 4 shows an example of a recording format of a signal recorded on a DCC subtrack, and FIGS. 5 and 6 record a start marker on the subtrack. An example of the recorded data is shown.

In FIG. 3, the magnetic tape cueing device is
A magnetic tape 104 having a sub-track for realizing a cue, a first reel stand 101 for winding the magnetic tape 104, a second reel stand 102 for sending out the magnetic tape 104, and a magnetic tape 104 are recorded. From the output result of the head 103 for reading the information of the sub-track, the amplifier 2 for amplifying the output result of the head 103, the envelope detection circuit 3 for detecting the recording shape of the sub-track from the output result of the amplifier 2, and the output result of the envelope detection circuit 3. A cycle detection circuit 4 for detecting a recording cycle of burst recording, a delay circuit 11 for delaying the output result of the cycle detection circuit 4 by one sample, and a comparison for calculating a ratio of both output results of the cycle detection circuit 4 and the delay circuit 11. A circuit 5, a marker discriminating circuit 6 for discriminating a marker type from a ratio output from the comparing circuit 5, and a marker discriminating circuit 6 A system controller 7 for determining the operation flow of the cue function by the determination result, the magnetic tape 104 by the output of the system controller 7
It is composed of a mechanism driving means 10 for changing the traveling of the vehicle.

Further, in FIG. 3, the magnetic tape 104, the first reel base 101, the second reel base 102, and the head 103 constitute a mechanism 1.

In FIG. 4, (A) shows a recording format of a sub track in a normal state which does not include marker information,
(B) is a subtrack recording format when a start marker indicating the beginning of a program is recorded on the subtrack, and (C) is a subtrack recording format when a reverse marker indicating a sector inversion position is recorded on the subtrack. Indicates. When two cycles of the normal recording format are set as one frame, the continuous recording length when recording the start marker corresponds to 16 frames, and the continuous recording length when recording the reverse marker is 32 frames. Equivalent to.

In FIG. 5, (A) shows an example of the recording format of the sub-track in which the start marker is recorded from the normal recording state, and (B) shows the output waveform from the envelope detection circuit 3 at this time. Is an example of.

In FIG. 6, (A) shows an example of the recording format of the sub-track in which the start marker is recorded from the non-recording portion, and (B) shows the output waveform from the envelope detection circuit 3 at this time. Is an example of. In addition,
The arrows in FIGS. 4 and 5 indicate the direction in which the search is performed, and the numbers indicate the sampling points at which the cycle detection circuit 4 detects the cycle of the envelope.

The operation of the magnetic tape cueing device configured as described above will be described below.

The operation of the conventional magnetic tape cueing device configured as shown in FIG. 3 when cueing the magnetic tape 104 on which the sub-track is recorded in the recording format as shown in FIG. An example will be described in which the position of the start marker is cued by running the magnetic tape at the position.

The magnetic tape 104 is run at high speed in the direction of the arrow in FIG. 5 (A) by winding the first reel stand. At this time, the head 103 reproduces the sub-track signal recorded on the magnetic tape 104. The signal recorded on the sub-track reproduced by the head 103 is amplified by the amplifier 2 and is shown in FIG.
Becomes the waveform of.

The period detection circuit 4 is an envelope detection circuit 3
Is started at the rising edge of the output waveform of, and the period from the previous rising edge of the output waveform of the envelope detection circuit 3 to this rising edge is measured. The delay circuit 11 delays the cycle information output by the cycle detection circuit 4 by one rising edge.

The magnetic tape 10 whose head 103 is shown in FIG.
4 when the position of 4 is reached,
And the delay circuit 11 outputs T2. Comparison circuit 5
Compares the output T3 of the period detection circuit 4 with the output result T2 of the delay circuit 11 and outputs the ratio. In this case, the ratio is approximately equal to 1.

When the magnetic tape 104 further travels and the head 103 advances to the position shown in FIG. 5, the cycle detecting circuit 4
Outputs T4, and the delay circuit 11 outputs T3. The comparison circuit 5 outputs the ratio of T3 and T4. In this case, a ratio of about 8 is output.

The marker discriminating circuit 6 discriminates the marker based on the output result of the comparing circuit 5. In the example of FIG. 5, when the head 103 reaches the position of, normal recording is output to the system controller 7,
When is reached, the start marker detection is output.

When the marker discriminating circuit 6 outputs a normal recording, the system controller 7 continuously instructs the driving means 10 to drive the magnetic tape 104 at a high speed, and when the marker discriminating circuit 6 detects a start marker. Instructs the driving means 10 to stop the magnetic tape 104. The drive means 10 drives the mechanism 1 according to an instruction from the system controller 7 to change the running state of the magnetic tape 104.

In this manner, the conventional magnetic tape cueing device carries out a cueing operation of the program recorded on the tape.

[0019]

However, in the conventional magnetic tape cueing device as described above, when the recording is suddenly started from the non-recorded area of the magnetic tape 104 from the start marker as shown in FIG. , When the head 103 comes to the position shown in FIG.
Although 1 is output, the output of the delay circuit 11 becomes indefinite.

Therefore, when the marker information such as the start marker is recorded from the non-recorded state, the ratio between the continuous recording length of the recording shape correctly recorded on the sub-track and the burst period at the burst recording cannot be calculated. Therefore, there is a problem that the marker cannot be discriminated.

The present invention solves the above-mentioned conventional problems, and enables the detection of a marker during fast-forwarding of the magnetic tape even when a magnetic tape on which a marker is suddenly recorded is used from a non-recorded state. An object is to provide a magnetic tape cueing device.

[0022]

In order to solve the above problems, a magnetic tape cueing device of the present invention has a sub-track for cueing on a magnetic tape, and when recording a signal on the sub-track. There are two kinds of recording patterns, a burst recording pattern and a continuous recording pattern. In normal signal recording, the burst track recording pattern is used for recording on the sub-track, and specific information is recorded on the sub-track. When recording, a magnetic tape is used in which recording is performed on the sub-track with the continuous recording pattern, and the recording length of the continuous recording pattern is changed according to the difference in the recording information on the sub-track. And a magnetic tape having the sub-track, and a first reel for winding the magnetic tape. A table, a second reel table for sending out the magnetic tape, a head for reading a subtrack signal on the magnetic tape, an amplifier for amplifying a signal output from the head, and a subtrack recording from an output of the amplifier An envelope detection circuit for detecting the shape, a cycle detection circuit for detecting the cycle of the envelope of the envelope detection circuit, a tape speed detection means for detecting the running speed of the magnetic tape, and a normal recording from the output of the tape speed detection means. The reference calculation circuit for calculating the burst period at the time, the comparison circuit for comparing the output of the period detection circuit and the output of the reference calculation circuit to obtain the ratio, and the recording on the sub-track based on the ratio output by the comparison circuit The marker discriminating circuit for detecting the cue information obtained and the output of the marker discriminating circuit controls the running of the tape. And a system controller that, by the output of the system controller is made and a driving means for changing the traveling state of the magnetic tape.

According to a second aspect of the invention, the tape speed detecting means detects the first reel cycle detecting means for detecting the rotation cycle of the reel for winding the magnetic tape, and the rotation cycle of the reel for supplying the magnetic tape. Second reel cycle detecting means for detecting, the first reel cycle detecting means, and the second reel cycle detecting means.
Reel cycle calculating means for calculating the moving speed of the magnetic tape based on both detection results of the reel cycle detecting means, and the reel cycle calculating means is the square of the output result of the first reel cycle detecting means and the first reel cycle detecting means. The sum of the output results of the two reel cycle detecting means and the square is calculated, and the running speed of the magnetic tape is obtained from the calculated result.

According to a third aspect of the present invention, the tape speed detecting means detects a first reel cycle detecting means for detecting a rotation cycle of a reel for winding the magnetic tape, and a rotation cycle of a reel for supplying the magnetic tape. Second reel cycle detecting means for detecting, the first reel cycle detecting means, and the second reel cycle detecting means.
And a reel cycle calculating means for calculating the moving speed of the magnetic tape based on both detection results of the reel cycle detecting means, and the reel cycle calculating means outputs the output result of the first reel cycle detecting means and the second reel. The sum of the output result of the cycle detecting means is calculated, and the approximate value of the running speed of the magnetic tape is obtained from the calculated result.

[0025]

According to the present invention, when the magnetic tape is run at a high speed to perform cueing, the recording cycle of the recording signal of the sub-track detected by the head during the high speed running is controlled by the envelope detection circuit. The cycle of the burst recording pattern calculated by the reference calculating circuit from the running speed during high speed running measured by the cycle detecting circuit and detected by the tape speed detecting means and the output result of the cycle detecting circuit by the comparing circuit. The marker discriminating circuit discriminates the kind of the signal recorded on the sub-track according to the amount of the comparison output, and the system controller changes the running of the magnetic tape according to the discriminating result. By doing so, it is possible to realize the cueing function even in a tape where a marker is suddenly recorded from a non-recorded state. It made.

Further, in the present invention, the reel cycle calculating means determines a sum of the square of the output result of the first reel cycle detecting means and the square of the output result of the second reel cycle detecting means. The traveling speed of the magnetic tape can be obtained by comparing with the table value of.

Further, in the present invention, the reel cycle calculating means compares the sum of the output result of the first reel cycle detecting means and the output result of the second reel cycle detecting means with a predetermined table value. The approximate speed at which the magnetic tape travels can be calculated.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a block diagram of a magnetic tape cueing device according to an embodiment of the present invention, and FIG. 2 shows a recording example in which a start marker is recorded on a subtrack.

In FIG. 1, the magnetic tape cueing device is
A magnetic tape 104 having a sub-track for realizing a cue, a first reel stand 101 for winding the magnetic tape 104, a second reel stand 102 for sending out the magnetic tape 104, and a magnetic tape 104 are recorded. From the output result of the envelope 103 which detects the recording format of the sub-track from the output result of the amplifier 2, the head 103 which reads the information of the sub-track, the amplifier 2 which amplifies the output result of the head 103, and the output result of the envelope detection circuit 3. A cycle detection circuit 4 for detecting a recording cycle of burst recording,
A first cycle detection circuit 91 for detecting the rotation cycle of the first reel stand, a second cycle detection circuit 92 for detecting the rotation cycle of the second reel stand, and an output result of the first cycle detection circuit 91. And reel cycle calculation means 93 for calculating the running speed of the magnetic tape 104 from the output result of the second cycle detection circuit 92.
And the reference calculation circuit 8 for calculating the burst cycle of burst recording of the sub-track at the time of normal (that is, no marker recording) recording from the output result of the reel cycle calculation means 93, both the cycle detection circuit 4 and the reference calculation circuit 8. A comparison circuit 5 for calculating a ratio of output results, a marker judgment circuit 6 for judging a marker type from the ratio output by the comparison circuit 5, and a system for judging an operation transition of a cue function based on the judgment result of the marker judgment circuit 6. The magnetic tape 104 depends on the output results of the controller 7 and the system controller 7.
It is composed of a mechanism driving means 10 for changing the traveling of the vehicle.

Further, in FIG. 1, the magnetic tape 104, the first reel base 101, the second reel base 102, and the head 103 constitute a mechanism 1.

Further, in FIG. 1, the first reel cycle detecting means 91, the second reel cycle detecting means 92 and the reel cycle calculating means 93 constitute tape speed detecting means 9.

In FIG. 2, (A) shows a recording format in which a start marker is recorded on the sub-track, and (B) shows from the envelope detection circuit 3 when the magnetic tape recorded as shown in (A) is reproduced at a high speed. Output waveform of
(C) is a waveform showing the rotation cycle of the first reel base 101,
(D) shows a waveform indicating the rotation cycle of the first reel stand 102. Further, T2 to T4 are the periods of the output waveform of the envelope detection circuit 3 in (B), and RT1 to RT8 are the first.
Of the reel table, RS1 to RS8 indicate the cycle of rotation of the second reel table.

The operation of the magnetic tape cueing device of this embodiment constructed as described above will be described.

FIG. 2A shows the operation of the magnetic tape cueing device according to the present embodiment for cueing the magnetic tape 104 having subtracks recorded in the recording format shown in FIG. 2A. An example will be described in which the magnetic tape recorded as shown is searched in the direction of the arrow to locate the position of the start marker.

The magnetic tape 104 is the first reel base 101.
By being wound up, it can be driven at high speed in the direction of the arrow in FIG. At this time, the head 103 reproduces the sub-track signal recorded on the magnetic tape 104. The signal recorded on the sub-track reproduced by the head 103 is amplified by the amplifier 2 and has the waveform of FIG.

The period detection circuit 4 is an envelope detection circuit 3
Is started at the rising edge of the output waveform of, and the period from the previous rising edge of the output waveform of the envelope detection circuit 3 to this rising edge is measured.

The tape speed detecting means 9 outputs the tape running speed calculated by the reel cycle calculating means 93 every time the first reel cycle detecting means 91 or the second reel cycle detecting means 92 outputs a cycle. The reference calculation circuit 8 calculates and outputs the burst recording length during normal recording (no marker is recorded) based on the running speed of the magnetic tape calculated by the tape speed detecting means 9.

The magnetic tape 10 whose head 103 is shown in FIG.
The cycle detection circuit 4 outputs T3 when it has reached position 4 above. Further, the tape speed calculating means 9 has the most recent rotation cycle of the first reel base 101, RT3, and the most recent rotation cycle of the second reel base 102, RS.
The traveling speed of the magnetic tape 104 is obtained from 2 and output.

The reference calculating circuit 8 determines the burst recording period at the time of recording, the magnetic tape speed at the time of recording and the tape speed detecting means 9
It outputs the burst recording period during high speed running of the magnetic tape obtained by dividing by the ratio to the tape speed during cueing output by. At this time, the value output by the reference calculation circuit 8 is substantially equal to T3.

The comparison circuit 5 compares T3 which is the output of the cycle detection circuit 4 with the output value of the reference calculation circuit 8 and outputs the ratio. In this case, the ratio becomes a value almost equal to 1.
When the magnetic tape 104 further travels and the head 103 advances to the position shown in FIG. 2, T4 is output from the cycle detection circuit 4.

The tape speed detecting means 9 outputs the tape speed calculated from the most recent rotation cycle RT7 of the first reel stand and the most recent rotation cycle RS7 of the second reel stand. The reference calculation circuit 8 outputs the value of the burst recording period from the output result of the tape speed detecting means. At this time, the value output by the reference calculation circuit 8 is a value that is approximately ⅛ of T4. Further, the ratio of the output result of the cycle detection circuit 4 output from the comparison circuit 5 and the output result of the reference calculation circuit 8 is about 8.

The marker discrimination circuit 6 discriminates a marker according to the output result of the comparison circuit 5. In the example of FIG. 2, normal recording is output to the system controller 7 when the head 103 has reached the position of, and start marker detection is output when the head 103 has reached.

The system controller 7 continuously instructs the driving means 10 to run the magnetic tape 104 at a high speed when the marker discriminating circuit 6 outputs normal recording, and drives when the marker discriminating circuit 6 detects a start marker. The means 10 is instructed to stop the magnetic tape 104. The drive means 10 drives the mechanism 1 according to an instruction from the system controller 7 to change the running state of the magnetic tape 104.

Therefore, even if the position immediately before the marker recording portion is in the non-recording state, the reference calculation circuit 8 can always output the burst recording cycle according to the tape speed at that time, and therefore the marker detection is performed. (That is, it is possible to obtain the ratio between the burst recording period and the continuous recording length).

Next, a case corresponding to claim 2 of the present invention will be described. In this case, in the tape speed detecting means 9 in the magnetic tape cueing device, the rotation cycle of the first reel base is detected by the first cycle detection circuit 91, and the rotation cycle of the second reel base is detected as the second. Detected by the cycle detection circuit 92,
The reel cycle calculation means 93 calculates the sum of squares of both detection results and compares it with a predetermined table value to detect the tape speed.

The relationship between the sum of squares of the rotation cycle of the first reel base 101 and the second rotation cycle of the second reel base 102 and the tape speed at that time is as follows. , The rotation cycle of the second reel base 102 is RS,
Letting S be the total cross-sectional area of the tape wound on both reel stands and both reel hubs for winding the tape on both reel stands, and letting the running speed of the tape be V, it is expressed by Formula 1.

[0048]

[Equation 1]

Further, the table value can be easily created by calculating the formula 1 in advance.

Next, a case corresponding to claim 3 of the present invention will be described. In this case, the tape speed detecting means 9 in the magnetic tape cueing device detects the rotation cycle of the first reel stand by the first cycle detecting circuit 91, and the rotation cycle of the second reel stand is determined by the second cycle. Detected by the cycle detection circuit 92,
The reel cycle calculation means 93 calculates the sum of both detection results and compares it with a predetermined table value to detect the tape speed.

The relationship between the sum of the rotation cycle of the first reel base 101 and the rotation cycle of the second reel base 102 and the tape speed at that time is as follows.
Let T be the rotation cycle of the second reel stand 102, and let S be the sum of the cross-section seats of the tape wound on both reel stands and both reel hubs for winding the tape on both reel stands. When the winding diameter of the wound tape is R2 and the running speed of the tape is V, it can be expressed by Equation 2.

[0052]

[Equation 2]

In the above formula 2, the winding diameter R2 of the second reel stand exists in the relationship between (RT + RS) and V. R2 has the smallest value when all the tapes are wound on the first reel stand, and has the largest value when all the tapes are wound on the second reel stand. A value is given to R2 and a value in the table is created in advance.

The tape speed calculated based on this table has an error depending on the winding position of the tape at that time. However, the amount of change in R2 is limited,
If the amount of this error is small with respect to the difference between the cycle of sub-track burst recording and the type of continuous recording length at the time of marker recording, the magnetic tape cueing device can perform accurate cueing.

The tape speed detecting means 9 according to the second aspect can simplify the structure of the reel cycle calculating means 93 as compared with the tape speed detecting means according to the second aspect.

[0056]

As described above, according to the present invention, even when the running speed of the magnetic tape is changed at a high speed and the recorded portion immediately before the change of the running speed of the magnetic tape or the marker is not recorded,
By calculating the running speed of the magnetic tape from the rotation cycle of the reel stand, the ratio between the continuous recording length of the marker recording section and the burst recording burst cycle during normal recording (no marker recording) can be accurately calculated. Since the marker can be accurately discriminated based on the difference in continuous recording length during high-speed running, an excellent magnetic tape cueing device that enables accurate cueing can be realized.

[Brief description of drawings]

[0057]

FIG. 1 is a block diagram of a magnetic tape cueing device of the present invention.

[0058]

FIG. 2 is a diagram showing an example in which a start marker is recorded on a magnetic tape used in the present invention.

[0059]

FIG. 3 is a block diagram of a conventional magnetic tape cueing device.

[0060]

FIG. 4 is a diagram showing an example of a recording pattern of a magnetic tape used in a conventional example.

[0061]

FIG. 5 is a diagram showing an example in which a start marker is recorded on a magnetic tape used in a conventional example.

[0062]

FIG. 6 is a diagram showing an example in which a start marker is recorded from a non-recorded state on a magnetic tape used in a conventional example.

[0063]

[Explanation of symbols]

 1 Mechanism 2 Amplifier 3 Envelope Detection Circuit 4 Cycle Detection Circuit 5 Comparison Circuit 6 Marker Discrimination Circuit 7 System Controller 8 Reference Calculation Circuit 9 Tape Speed Detection Means 10 Driving Means 11 Delay Circuit 91 First Reel Cycle Detection Circuit 92 Second Reel Period detection circuit 93 Reel period calculation means 101 First reel stand 102 Second reel stand 103 Head 104 Magnetic tape

Claims (3)

[Claims] 1. A magnetic tape has a sub-track for cueing, and when recording a signal on the sub-track, two types of recording patterns, a burst-recording pattern and a continuous recording pattern, are provided. In normal signal recording, recording on the sub-track is performed by a burst recording pattern, and when recording specific information on the sub-track, recording is performed on the sub-track by the continuous recording pattern. A device for performing cueing from a high speed running using a magnetic tape recorded by changing the recording length of the continuous recording pattern according to the difference in recording information on the sub-track, A tape, a first reel stand for winding the magnetic tape, a second reel stand for sending out the magnetic tape, and a support on the magnetic tape. A head for reading a signal of a track, an amplifier for amplifying a signal output from the head, an envelope detection circuit for detecting a recording shape of a sub-track from the output of the amplifier, and a cycle for detecting an envelope cycle of the envelope detection circuit. A detection circuit, a tape speed detection means for detecting the traveling speed of the magnetic tape, a reference calculation circuit for calculating a burst cycle at the time of normal recording from the output of the tape speed detection means, an output of the cycle detection circuit and the reference. A comparison circuit that compares the outputs of the calculation circuits to obtain the ratio, a marker discrimination circuit that detects cue information recorded on a sub-track based on the ratio output by the comparison circuit, and an output of the marker discrimination circuit By the system controller that controls the running of the tape and the output of the system controller A drive unit for changing the running state of the magnetic tape, and when the magnetic tape is run at a high speed for cueing, a recording cycle of a subtrack recording signal detected from the head during high speed running Is measured by the envelope detection circuit and the cycle detection circuit, and the cycle of the burst recording pattern calculated by the reference calculation circuit from the measured value result and the running speed during high speed running detected by the tape speed detecting means is described above. Comparison is made by a comparison circuit, and the marker discrimination circuit discriminates the kind of the signal recorded on the sub-track according to the amount of the comparison output ratio, and the system controller runs the magnetic tape according to the discrimination result. Magnetic tape cueing device characterized by changing the cue to perform cueing. 2. The tape speed detection means detects a rotation cycle of a reel that winds the magnetic tape, and a second reel cycle detection means that detects a rotation cycle of a reel that supplies the magnetic tape. Reel cycle calculating means, and reel cycle calculating means for calculating the moving speed of the magnetic tape based on the detection results of both the first reel cycle detecting means and the second reel cycle detecting means. Is the square of the output result of the first reel cycle detecting means and 2 of the output result of the second reel cycle detecting means.
2. The magnetic tape cueing device according to claim 1, wherein the sum of the power of the magnetic tape is calculated and the running speed of the magnetic tape is obtained from the calculated result. 3. The tape speed detecting means detects a rotation cycle of a reel for winding the magnetic tape, and a second reel cycle detecting means detects a rotation cycle of a reel for supplying the magnetic tape. Reel cycle calculating means, and reel cycle calculating means for calculating the moving speed of the magnetic tape based on the detection results of both the first reel cycle detecting means and the second reel cycle detecting means. Calculates the sum of the output result of the first reel cycle detection means and the output result of the second reel cycle detection means, and obtains a rough value of the running speed of the magnetic tape from the calculation result. The magnetic tape cueing device according to claim 1.