JP2001268496A - Information reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information reproducing device capable of accurately specifying the recording mode of information being reproduced from a tape recording medium. SOLUTION: A tape traveling speed at the time of recording is discriminated (S3, S4 and S33) and then whether it is digital information recorded in a D-VHS mode or analog information recorded in a VHS mode is discriminated (S5-S11). For instance, when reproduction is performed in the HS mode of D-VHS and a sub code is detected or when a reproducing signal level LPBENV1 is higher than a prescribed level L1, it is discriminated as the information recorded in the HS mode (S5, S6, S7 and S34). When the sub code is not detected and the reproducing signal level LPBENV1 is lower than the prescribed level L1, a reproducing operation is performed in the VHS mode, and when the reproducing signal level LPBENV2 is higher than the prescribed level L2, it is discriminated as the information recorded in an SP mode (S5, S8 and S35).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information reproducing apparatus capable of reproducing both analog information and digital information recorded on a tape recording medium at a plurality of tape running speeds, and more particularly, to an automatic recording mode for information being reproduced. Which has the function of determining

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 8-63875 discloses an information reproducing apparatus capable of reproducing both analog information and digital information recorded on a recording medium and having a function of automatically determining whether the information is analog information or digital information. What is described in the gazette is conventionally known. In this device, a predetermined frequency component of a portion corresponding to a synchronization signal is extracted from a signal reproduced from a recording medium, and whether the information is analog information or digital information is determined based on the level of the extracted component.

[0003]

However, in the above-mentioned conventional apparatus, a synchronizing signal separating circuit and a filter for extracting a predetermined frequency component are required, and the configuration is complicated. Also, if the digital information contains a frequency component close to the analog information, the digital information may be erroneously determined to be analog information even though the digital information is digital information.

The above publication does not disclose a recording mode when analog information and digital information are recorded at a plurality of tape traveling speeds, that is, a method for determining a combination of a type of information and a tape traveling speed. Was.
The present invention has been made in view of this point, and even when analog information or digital information is recorded at a plurality of tape traveling speeds on a tape recording medium, the recording mode can be accurately determined with a relatively simple configuration. It is an object of the present invention to provide an information reproducing apparatus capable of performing the above.

[0005]

According to a first aspect of the present invention, there is provided a first recording mode in which digital information is recorded at a first tape running speed, and
A second recording mode in which digital information is recorded at a second tape traveling speed lower than the tape traveling speed of the first recording mode;
A tape recording state recorded in one of a third recording mode in which analog information is recorded at the tape traveling speed and a fourth recording mode in which analog information is recorded at the second tape traveling speed. In an information reproducing apparatus that reproduces information from a recording medium, a recording speed determining unit that determines a tape traveling speed when information is recorded on the tape-shaped recording medium, and a level of a signal reproduced from the tape-shaped recording medium. Level detecting means for detecting the digital information, and sub-code detecting means for detecting the presence or absence of a sub-code unique to the digital information. When it is determined that the tape traveling speed is the first recording mode, it is determined whether the recording mode is the first recording mode based on the outputs of the level detecting means and the subcode detecting means. It is determined whether the recording mode is the third recording mode, and when the recording speed determining unit determines that the tape traveling speed when the information is recorded is the second tape traveling speed, It is characterized in that it is determined whether the mode is the second recording mode or the fourth recording mode based on the outputs of the level detecting means and the subcode detecting means.

When a relative angle between a gap of a magnetic head for recording information on the tape-shaped recording medium and a recording track on the tape-shaped recording medium is defined as a head azimuth, the digital information is a magnetic field for recording the analog information. The information reproducing apparatus is recorded on the tape-shaped recording medium by a magnetic head having a head azimuth different from the head, and the information reproducing apparatus has a head azimuth corresponding to the head azimuth of the magnetic head for recording the analog information. It is desirable to have a head and a magnetic head for reproducing digital information having a head azimuth corresponding to the magnetic head for recording the digital information.

The relative position between the information recording track on the tape-shaped recording medium and the reproducing head for reproducing information from the information recording track is set so that the level of the signal reproduced from the recording medium becomes substantially maximum. It is preferable that an auto-tracking control to be performed be performed, and the recording mode be determined by using an output of the level detecting means after the end of the auto-tracking control.

The tape-shaped recording medium is mounted on the information reproducing apparatus in a state of being housed in a cassette. The cassette includes a cassette in which the cassette is mainly used for recording digital information. It is preferable that the recording mode is determined by referring to the cassette type information. Further, the information recording / reproducing apparatus may be configured by adding the function of recording the analog information and the digital information to the information reproducing apparatus.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a main part of an information recording / reproducing apparatus according to an embodiment of the present invention. The information recording / reproducing apparatus is a D-VHS (registered trademark).
Compliant with the standards, MPEG (Motion Picture Expert Group)
p) Recording digital information such as two transport streams on a magnetic tape as a tape-shaped recording medium, reproducing the recorded digital information from the magnetic tape, and using the VHS (registered trademark) standard or S-VHS (registered trademark). A) A VTR that conforms to the standard and is capable of recording analog information such as an analog video signal such as an NTSC signal on a magnetic tape and reproducing the recorded analog information from the magnetic tape. In the following description, a mode for recording and reproducing digital information is called a D-VHS mode, and a mode for recording and reproducing analog information is called a VHS mode.
In this VTR, in the VHS mode, recording / reproduction in the SP mode (third recording mode) in which the tape traveling speed is the standard speed (33.33 mm / sec) and in the EP mode in which the tape traveling speed is 1/3 of the standard speed, L which is 1/2 of the standard speed
Reproduction in the P mode (fourth recording mode) is possible. In the D-VHS mode, the HS mode (a mode in which recording and reproduction is performed at the same tape running speed as the SP mode in the VHS mode, a first recording mode), Tape running in STD mode (mode for recording / reproducing at the same tape running speed as LP mode in VHS mode, second recording mode) and LS3 mode (1/2 of EP mode in VHS mode (1/6 of SP mode)) Recording / reproduction in a mode of recording / reproduction at a speed). The magnetic tape is stored in a cassette, and information (specifically, indicated by the presence or absence of a hole at a predetermined position) indicating that the magnetic tape is a D-VHS cassette is added to the cassette.

The information recording / reproducing apparatus according to the present embodiment records analog information on a magnetic tape 50 as shown in FIG.
A VHS magnetic head 1 for reproducing from the magnetic tape 50, a D-VHS magnetic head 6 for recording digital information on the magnetic tape 50 and reproducing from the magnetic tape 50, and an output signal of each magnetic head Amplifiers 3 and 7 for amplifying the signal, a VHS signal processor 5 for performing signal processing for recording and reproducing analog information, a D-VHS signal processor 6 for performing signal processing for recording and reproducing digital information,
System control unit 11 for controlling the entire recording / reproducing apparatus
A drum motor 14 for driving a rotary drum (not shown) on which the magnetic heads 1 and 6 are mounted; a capstan motor 13 for driving a capstan (not shown) for running the magnetic tape 50; And a servo unit 12 for driving and controlling the motor.

The magnetic heads 1 and 6 comprise a head for a first channel (CH1) and a head for a second channel (CH2) which are arranged on the rotating drum at an angular interval of 180 degrees, respectively. By alternately using the heads, information is recorded by obliquely scanning the magnetic tape 50 wound around the rotary drum at an angle slightly larger than 180 °, and the recorded information is reproduced. FIG.
Is a diagram showing a recording track pattern on the magnetic tape 50. A control track on which a control pulse as control information is recorded is provided near the lower end of the magnetic tape 50. FIG. In the figure, the hatched tracks are the tracks of CH1, the tracks without hatching are the tracks of CH2, and arrows A1 and A2 indicate the scanning trajectories of the magnetic heads of CH1 and CH2 during normal reproduction, respectively. . Arrow lines B1 and B2 are scanning trajectories at the time of search reproduction (when reproduction is performed at a higher tape running speed than at the time of recording), respectively. The recording track pattern as shown in FIG. 2 is a well-known recording track pattern adopted in a VTR or the like based on the VHS standard.

In this embodiment, the head azimuth of the VHS magnetic head 1, that is, the relative angle between the head gap and the recording track on the magnetic tape is ± 6 degrees with respect to the width direction of the recording track (CH1 head is +6 degrees). The head azimuth of the D-VHS magnetic head 6 is set to ± 30 degrees (the CH2 head is set to −30 degrees if the CH1 head is set to +30 degrees). I have. Therefore, when a magnetic tape recorded in the VHS mode (VHS magnetic head) is reproduced in the D-VHS mode (D-VHS magnetic head), or conversely, in the D-VHS mode (D-VHS magnetic head). When the recorded magnetic tape is reproduced in the VHS mode (magnetic head for VHS), the reproduced signal (magnetic head output signal) is significantly reduced due to azimuth loss. In the present embodiment, focusing on this point, as described later, it is determined whether the information on the magnetic tape being reproduced is recorded in the VHS mode or recorded in the D-VHS mode. The determination is made based on the level of the head output signal).

A D-VHS signal processing section 10 converts an input digital signal into a signal suitable for recording, and performs a process reverse to that at the time of recording on a reproduced signal from a magnetic tape and outputs the processed signal. And a CPU (Central Processing Uniform) that controls the D-VHS signal processing unit 10.
t) 101 is provided, and the CPU 101 is connected to the system control unit 11 via the bidirectional serial data bus 15. According to the D-VHS standard, a subcode unique to digital information is recorded in a subcode area near the lower end (control track) of the magnetic tape 50, and the subcode is reproduced from the subcode area. When a sub-code is detected in the reproduction signal in the circuit 102, the detection information is transmitted to the system control unit 11 via the CPU 101 and the data bus 15.

The output of the reproduction amplifier 3 is supplied to an envelope detection circuit 4, and the detection output is supplied to a system control unit 11
Is input to The output of the reproduction amplifier 7 is supplied to an envelope detection circuit 9 via a high-pass filter 8, and the detection output is input to a system control unit 11.

A system control unit 11 outputs a capstan FG pulse (CFG pulse) having a frequency proportional to the rotation speed of the capstan and a control pulse reproduced from a control track of the magnetic tape 50.
And the servo unit 12, a drum pulse indicating the rotation phase of the rotating drum and a drum FG pulse proportional to the rotation speed of the rotating drum are input to the servo unit 12. These input pulses are generated by a well-known magnetic head or pulse generator.

The system control section 11 is further connected to a cassette type detection switch 17 for detecting information indicating the type of the cassette containing the magnetic tape (D-VHS cassette or other cassette). On / off information is input. The system control unit 11 determines whether the information being reproduced is recorded in the VHS mode or D-VHS mode based on each of the input signals, as described later. While transmitting to the CPU 101 via the data bus 15, the mode switching signal MSW corresponding to the determination result is supplied to the VHS signal processing unit 5 and the switch circuit 2. Switch circuit 2
Are turned on when in the D-VHS mode, and the output of the VHS magnetic head 1 is grounded. The system control unit 11 further controls the operation of the device according to an input signal from an operation switch (not shown) or the like.

The servo section 12 is connected to the system control section 11 via a serial data bus 16, and the system control section 11 transmits the mode discrimination result and the tracking control signal (on the magnetic head and the magnetic tape) via the data bus 16. (A signal for controlling the relative position with respect to the recording track) is supplied to the servo unit 12. The servo unit 12 includes a capstan motor 13 and a drum motor 14 based on various input signals.
Is controlled so that information is recorded on the magnetic tape 50 in a predetermined recording track pattern during recording, and the magnetic head 1 or 6 moves the recording tracks on the magnetic tape in a desired pattern during reproduction. The scanning is controlled (see arrows A1, A2, B1, B2 in FIG. 2). Since the present invention is characterized by a method of determining the mode at the time of reproduction, a circuit such as a recording amplifier for supplying a recording current to the magnetic heads 1 and 6 is not shown in FIG.

FIGS. 3 and 4 show the system controller 11 of FIG.
5 is a flowchart of a mode determination process for determining whether the information being reproduced is digital information or analog information, and the mode of the VTR is determined to be a D-VHS mode. Alternatively, the mode is set to the VHS mode.

First, in step S1, it is determined whether or not the magnetic tape is being reproduced. If not, the process is terminated. If it is being reproduced, it is determined whether or not a control pulse has been input (step S2). ). If the control pulse has not been input, the information is not recorded in the part of the magnetic tape being reproduced, so that the processing is terminated. If the control pulse has been input, it is determined whether or not the recording mode is the EP mode. (Step S3).

This determination is made by FG determination. The FG discrimination is performed by counting the number NCFG of capstan FG pulses generated during the control pulse input interval period. That is, when the recording mode is the EP mode of the VHS mode, the count number NCFG is set to N.
Assuming EP, in LP mode NCFG = 3/2 × NE
P, and in the SP mode, NCFG = 3 × NEP, while in the LS3 mode of the D-VHS mode, NCFG = 3 × NEP.
= 1/2 × NEP, and in STD mode NCFG =
3/2 × NEP, and in the HS mode, NCFG = 3 ×
Since the result is NEP, by detecting this difference, the tape traveling speed at the time of recording can be determined. However, in the FG determination, it is not possible to distinguish between the LP mode and the STD mode in which the tape running speed is the same, and similarly, it is also not possible to distinguish between the SP mode and the HS mode.

If it is determined in step S3 that the recording mode is the EP mode, it is determined whether the recording mode is the VHS mode (step S13).
It is determined whether or not the mode is set (step S4). As a result, when the mode is the LS3 mode, it is determined that the mode is the D-VHS mode (step S12). When the mode is not the LS3 mode, the tape running speed is changed to the standard speed (SP mode or SP mode) according to the result of the FG determination. The speed is set to 1/2 (the speed corresponding to the HS mode) or the standard speed (the speed corresponding to the LP mode or the STD mode), and the process proceeds to step S5.

In step S5, it is determined whether or not the auto tracking control has been completed. The auto-tracking control changes the relative position between the scanning trajectory of the magnetic head and the recording track on the magnetic tape (hereinafter referred to as "tracking"), and the optimum position where the reproduction signal level (envelope detection circuit output) becomes almost maximum. And controls tracking to its optimum position. At first, since the answer to step S5 is negative (NO), the process proceeds to step S21 in FIG. 4 to determine whether or not the first auto-tracking control is performed. At first, since this answer is affirmative (YES), the cassette mounted on this VTR is D-VHS.
It is determined whether it is of the type (step S22). As a result, if it is of the D-VHS type, the reproduction mode is set to the D-VHS mode (using the magnetic head 6), and the auto tracking control is executed (step S24).

When the auto-tracking control in the D-VHS mode is completed, the process proceeds from step S5 to step S6, where it is determined whether the reproduction mode is the D-VHS mode. In the case of the D-VHS mode, it is determined whether or not the CPU 101 of the D-VHS signal processing circuit 10 detects a sub-code unique to the D-VHS mode (step S).
7). As a result, when the subcode is detected, D
-Determine whether the mode is the VHS mode (step S
12). When no subcode is detected,
Output level LPBENV1 of envelope detection circuit 9
Is larger than the first predetermined level L1 (step S8). Here, the first predetermined level L1 is:
The magnetic tape recorded in the D-VHS mode is
The value is set to about 20% of the average level when reproduced in the mode. In step S8, LPBENV1> L
When it is 1, it is confirmed that the temporarily set D-VHS mode is correct (if the tape is recorded in the VHS mode, the output level LP is determined by the difference in head azimuth).
(Because BENV1 drops significantly and becomes smaller than the predetermined level L1), the determination of the D-VHS mode is determined (step S12).

On the other hand, when LPBENV ≦ L1,
Proceeding to step S10, it is determined whether the auto tracking control has been executed twice. Initially, the answer is negative (N
O), the process proceeds to step S21. At this time, since the answer in step S21 is negative (NO), it is determined in step S23 whether the cassette being loaded is a D-VHS cassette or not.
The automatic tracking control is executed in the mode (using the magnetic head 1) (step S25).

When the auto tracking in the VHS mode is completed, the process proceeds from step S5 to S6, and the answer to step S6 is negative (NO). Therefore, the process proceeds to step S9, where the output level LPBEN of the envelope detection circuit 4 is output.
It is determined whether V2 is greater than a second predetermined level L2. Here, the second predetermined level L2 is set to a value of about 20% of an average level when a magnetic tape recorded in the VHS mode is reproduced in the VHS mode. If LPBENV2> L2 as a result of the determination in step S9, it is confirmed that the setting of the VHS mode is correct (if the tape is recorded in the D-VHS mode, the output level LPBENV2 is remarkably increased due to the difference in head azimuth). (Step S13). Therefore, it is determined that the mode is the VHS mode. If LPBENV2 ≦ L2, the process proceeds to step S10, and since the answer is affirmative (YES), it is determined whether the cassette is a D-VHS cassette (step S11), and the cassette is a D-VHS cassette. At this time, the determination that the mode is the D-VHS mode is determined (step S12), and when the cassette is not the D-VHS cassette, the determination that the mode is the VHS mode is determined (step S13).

Since the envelope detection output level LPBENV1 or LPBENV2 cannot be lower than the predetermined level L1 or L2 while the control pulse is being reproduced, step S11 is not normally executed. This is executed, for example, in the case of an abnormally recorded tape such as a tape in which only control pulses are recorded. In such a case, a determination according to the cassette type information is determined as a fail-safe measure. I have.

In the above description, the case where the D-VHS cassette is mounted is described. However, when the VHS cassette (a cassette other than the D-VHS cassette) is mounted, the first auto-tracking control is performed. VH
It is executed in the S mode, and if the determination that the mode is the VHS mode is not determined in the subsequent processing, the second time is executed in the D-VHS mode. Even when a D-VHS cassette is loaded, the recorded information may be analog information. Therefore, it is not possible to determine the recorded content only with the cassette type information. Since the possibility of recording in the VHS mode is high, by setting the order of the auto tracking control according to the information of the cassette type, the expected value of the time required for the determination can be reduced.

As described above, in the processing shown in FIGS. 2 and 3,
As a result of the FG determination (determination of the tape running speed at the time of recording), based on the level of the head output signal and the presence / absence of a subcode specific to the D-VHS mode, whether the recording was performed in the D-VHS mode (digital information was recorded). Or VHS)
It is determined whether or not recording was performed in the mode (analog information is recorded). Therefore, even when recording is performed at multiple tape running speeds, no special additional circuit is required Determination can be performed.

Next, referring to FIGS. 5 to 7, in the case of the VHS mode, it is determined whether the mode is the SP mode, the LP mode or the EP mode, and in the case of the D-VHS mode, the HS mode is determined. A process for determining whether the mode is the mode, the STD mode, or the LS3 mode will be described.

In FIG. 5, steps S1 to S11 perform the same processing as the corresponding steps in FIG. 3, and steps S41 to S47 in FIG. 6 perform the same processing as steps S5 to S11 in FIG. Step
Is the same process as in FIG.

E is determined by FG discrimination in step S3 in FIG.
When it is determined that the mode is the P mode, there is no other mode with the same tape running speed as the EP mode. Therefore, it is determined that the mode is the EP mode (step S31), and the mode is determined to be the LS3 mode in step S4. If it is determined, it is determined that the mode is the LS3 mode for the same reason (step S32). If the answer to step S4 is negative (NO), and the tape running speed during recording is the SP mode speed or the LP mode speed, it is determined whether or not the tape running speed is the SP mode speed, that is, the HS mode or the SP mode. It is determined whether or not there is (step S33). And HS
If the mode is the mode or the SP mode, the tape running speed is set to the speed of the SP mode and the process proceeds to step S5, while the tape running speed at the time of recording is the speed of the LP mode, that is, the STD mode or the LP mode. At this time, the tape running speed is set to the speed in the LP mode, and the process proceeds to step S41 in FIG.

When it is determined that the mode is the D-VHS mode by the processes of steps S5 to S11 and the process of FIG. 7, while it is determined that the mode is the HS mode (step S34), it is determined that the mode is the VHS mode. When done,
It is determined that the mode is the SP mode (step S3).
5). When it is determined that the mode is the D-VHS mode by the processes of steps S41 to S47 of FIG. 6 and the process of FIG. 7, while determining that the mode is the STD mode (step S48), it is determined that the mode is the VHS mode. When it is determined, it is determined that the mode is the LP mode (step S
49).

As described above, according to this embodiment, based on the level of the head output signal and the presence or absence of the sub-code specific to the D-VHS mode, as a result of the FG determination (determination of the tape running speed during recording). Since the recording mode is determined, that is, whether the recording is performed in the HS mode, the STD mode, the LS3 mode, the SP mode, the LP mode, or the EP mode, a plurality of tape running in the D-VHS mode or the VHS mode is performed. Even when the recording operation is performed at a high speed, accurate discrimination can be performed with a simple configuration without requiring a special additional circuit.

The present invention is not limited to the embodiment described above, and various modifications are possible. For example, the D-VHS mode or the VHS mode is used only based on the presence or absence of the sub-code specific to the D-VHS mode without using the head output signal.
The mode may be determined. That is, when the sub-code is detected, the D-VHS mode may be determined, and when the sub-code is not detected, the V-HS mode may be determined.

[0035]

As described in detail above, according to the present invention, when the recording speed discrimination means determines that the tape traveling speed at the time of recording is the first tape traveling speed, the tape is reproduced from the tape-shaped recording medium. Based on the signal level and / or the presence or absence of a sub-code specific to digital information, whether the recording mode at the time of recording is the first recording mode or the third recording mode.
The tape traveling speed at the time of recording is determined to be the second tape traveling speed. When it is determined that the tape traveling speed is the second tape traveling speed, the level of the signal reproduced from the tape-shaped recording medium and / or the digital information is determined. A first recording mode in which digital information is recorded to determine whether the recording mode at the time of recording is the second recording mode or the fourth recording mode based on the presence or absence of a specific subcode. Not only the discrimination between the first and second recording modes and the discrimination between the third recording mode and the fourth recording mode in which analog information is recorded, but also the tape traveling speed at the first tape traveling speed. The discrimination between a certain first recording mode and the third recording mode, and the discrimination between the second recording mode and the fourth recording mode in which the tape traveling speed is the second tape traveling speed can be easily performed. Configuration. It can be carried out without the need for special additional circuit.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of an information recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a recording track pattern on a magnetic tape and a scanning trajectory of a magnetic head.

FIG. 3 is a flowchart of a mode determination process executed by the system control unit of FIG. 1;

FIG. 4 is a flowchart of a mode determination process executed by the system control unit of FIG. 1;

FIG. 5 is a flowchart of a more specific mode determination process executed by the system control unit of FIG. 1;

FIG. 6 is a flowchart of a more specific mode determination process executed by the system control unit of FIG. 1;

FIG. 7 is a flowchart of a more specific mode determination process executed by the system control unit of FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 magnetic head for VHS 3 reproduction amplifier 4 envelope detection circuit (level detection means) 5 VHS signal processing circuit 6 magnetic head for D-VHS 7 reproduction amplifier 9 envelope detection circuit (level detection means) 10 D-VHS signal processing circuit 11 system Control unit (recording speed determination unit) 12 Servo unit 101 CPU 102 Signal processing circuit (sub data detection unit)

Claims (1)

[Claims] 1. A first recording mode in which digital information is recorded at a first tape traveling speed, and a second recording mode in which digital information is recorded at a second tape traveling speed lower than the first tape traveling speed. One of a recording mode, a third recording mode in which analog information is recorded at the first tape traveling speed, and a fourth recording mode in which analog information is recorded at the second tape traveling speed In an information reproducing apparatus that reproduces information from a tape-shaped recording medium recorded in a mode, a recording speed determining unit that determines a tape traveling speed when information is recorded on the tape-shaped recording medium; and A level detecting means for detecting a level of a reproduced signal; and a sub-code detecting means for detecting presence or absence of a sub-code unique to the digital information. Means, when it is determined that the tape running speed at the time of recording the information is the first tape running speed, based on the outputs of the level detecting means and the subcode detecting means, It is determined whether the recording mode is the third recording mode or the third recording mode, and the recording speed discriminating means determines that the tape traveling speed when information is recorded is the second tape traveling speed. When it is determined, it is determined whether the mode is the second recording mode or the fourth recording mode based on the outputs of the level detecting means and the subcode detecting means. Information playback device.