JPH08249758A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE: To omit the input setting operation by discriminating the kind of tapes, providing a mode for automatically setting the recording system and detecting the kind of cassette tapes from the existence of a detecting hole at the time of recording operation. CONSTITUTION: When the automatic discriminating mode is selected, the kind of cassettes is discriminated at the time point of receiving an instruction for recording by the operation of a recording button on a control panel 60. When it is discriminated to be D-cassette, it is judged that the digital recording is performed, and the digital signal input is selected by a switch 51 and also a digital signal processing circuit 54 is activated to start the recording operation. When it is not D-cassette, the setting of a manual mode changeover switch of the control panel 60 is ascertained. When the digital recording is selected and also in the case of S-cassette, the digital recording is started. The recording is not permitted in the case of V-cassette, and this effect is warned to the operator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus for digital image signals, and more particularly to a magnetic recording / reproducing apparatus compatible with existing analog VTRs.

[0002]

2. Description of the Related Art Currently, as a magnetic recording / reproducing apparatus for home use, an analog type V using a 1/2 inch wide tape is used.
TR has been put to practical use and is used for recording analog TV signals. On the other hand, the development of digital broadcasting as a next-generation TV broadcasting is in progress, and the practical use of various transmission methods such as digital transmission using satellites, terrestrial digital transmission, or cable transmission is under study. If digital broadcasting or transmission is realized, it is desired to realize a VTR of a digital recording system which records a digital signal as it is by utilizing the characteristic of digital transmission without deterioration in a transmission system. However, since the digital image signal has a larger amount of information than the analog image signal, the digital VTR has been put into practical use only in a special field such as a business use. However, recently, MPEG (Moving Picture)
Advances in image compression technology represented by the Experts Group) have led to downsizing of devices and their expansion into home use. Regarding these digital recording technologies,
Journal of the Television Society, Vol. 47, No. 6 (1993
, Pp. 814-825.

[0003]

Digital VT for home use
In addition to the digital VTR dedicated machine with its own recording format, the R format is compatible with the current analog VTR in terms of price, installation space, and utilization of conventional assets (analog recording tape). A system that enables analog and digital recording / reproduction on a stand is also conceivable. However, the following problems are expected in a system that combines both types. First, since the input source at the time of recording is different between analog recording and digital recording, it is necessary to select the recording method and the input source and confirm the coincidence, which complicates the operation at the time of recording. The possibility of erroneous operation increases. Secondly, there is a problem caused by a mixture of analog recording and digital recording of cassette tapes having the same shape. For example, in the case of recording with an existing analog VTR continuously or overwritten on a recorded tape, it is common to reproduce the tape once and confirm the contents. However, when both types of tapes are mixed, the operator cannot recognize the image because of the discrepancy of the reproduction methods even though the recording has already been performed by either method, and it is judged as a non-recording tape and overwritten. There is concern about accidental deletion. Furthermore, when digital recording tapes have come into circulation, it is not possible to confirm digital recording with the current VTRs using only the analog method, and the problem of erroneous erasure still arises.

An object of the present invention is a VT capable of recording and reproducing a digital signal while maintaining compatibility with the existing analog VTR.
It is an object of the present invention to provide a magnetic recording / reproducing apparatus having an analog / digital mode automatic discriminating function in R, a simple operation at the time of recording and reproducing, and a function of preventing an erroneous operation such as erroneous erasing.

[0005]

To achieve the above object, the present invention comprises a first recording / reproducing means for recording / reproducing an analog signal and a second recording / reproducing means for recording / reproducing a digital signal. In the magnetic recording / reproducing apparatus, a means for discriminating the type of the cassette tape based on the presence or absence of a detection hole for identification provided in the digital recording cassette tape, and a ratio of the frequency of the control signal to the rotation frequency of the capstan motor for transferring the tape. Means for discriminating the tape speed at the time of recording, means for discriminating the presence or absence of a digital recording signal by synchronous detection of reproduction output, and means for switching the recording and reproducing modes according to the discrimination result of the discriminating means. It was

Further, in a magnetic recording / reproducing apparatus for recording / reproducing only analog signals, means for detecting the type of the cassette tape depending on the presence / absence of a detection hole for identifying the cassette tape for digital recording, or the frequency of the control signal and the transfer of the tape. There is provided a digital signal detecting means for discriminating the tape speed during recording from the ratio of the rotation frequency of the capstan motor.

[0007]

When the recording operation is performed, the type of the cassette tape is determined, and when the digital recording cassette is inserted, the recording circuit and the input source are automatically selected so that the digital recording has priority. As a result, the operation of setting the input signal can be omitted. Further, since only digital signals are recorded on the digital tape, the tape can be easily managed. At the time of playback, the method that is most likely to be recorded according to the detection result of the cassette, such as the digital method for the digital cassette, is set to the initial setting, so that the time from the playback instruction to the actual start of image output can be increased. It can be shortened. In the case of the analog type dedicated machine, the reproducing operation is performed prior to the recording, and the recording is prohibited when the digital signal is detected by the means for detecting the presence or absence of the digital type signal, whereby the erroneous erasure due to the overwriting can be prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In this embodiment, a means for recording a digital signal is provided on the basis of a VHS standard VTR. According to the VHS standard, there are three types of tape speeds: standard mode (SP mode), standard speed 1/2 speed mode (LP mode), and 1/3 speed mode (EP mode). In the present embodiment, since the recording signal band of digital recording is wider than that of the analog method, it is difficult to narrow the track in order to secure the S / N of the reproduced signal.
In consideration of the advantage that the same setting as the conventional analog method can be used in the design, the tape speed is assumed to use the LP mode. FIG. 1 shows a block structure of a recording system of a magnetic recording / reproducing apparatus of the present invention, in which 1 is a rotary drum, 2 and 3 are guide posts, 4 is a magnetic tape, 5 and 6 are magnetic heads, and 7 is a DPG (Drum). Phase Generator (abbreviation of Phase Generator), 8 is a pinch roller, 9 is a CTL head, 10 is a capstan shaft, 11 is a capstan motor, 97 is a linear audio head, 55 is a cassette tape, 50, 5
6, 95 are recording amplifiers, 96 is a linear audio processing circuit, 51 is a switch circuit, 53 is an FM audio processing circuit, 5
4 is a digital signal processing circuit, 25 is a servo system controller (hereinafter referred to as servo system controller) block,
24 is a motor driver, 57 is an analog video signal processing circuit, 59 is a tuner block, 58 is a cassette hole detection circuit, 22, 61, 62 are input terminals, 21, 17, 3
1 is an output terminal, 12 is a VTR, 34 is a tuner and M
PEG decoder, 40 is a monitor TV, 33 is a bit compression digital signal input terminal, 35-39, 41-44 are input / output terminals, 60 is a record button, a reproduction button, various operation switches such as a manual analog / digital switch It is an operation panel on which is arranged.

The operation of digital recording will be described below.
The bit-compressed and modulated digital signal that has entered the terminal 33 is demodulated by the tuner and the MPEG decoder, and then V-compressed as a bit-compressed digital signal from the terminal 36.
It is transmitted to the input terminal 22 of TR12. The digital signal reproduced by the VTR 12 is output from the terminal 21, input to the input terminal 37 of the decoder 34, decoded into a composite video signal, a video signal is output from the terminal 38, and an audio signal is output from the terminal 39 and sent to the monitor television. VTR
The signal from 12 is also output from terminals 17 and 31,
It is sent to the monitor TV side.

Next, the operation of the VTR 12 will be briefly described.
In the analog VTR mode, the audio signal from the tuner 59 is transmitted to the audio head 97 via the linear audio processing circuit 96 and the recording amplifier 95 and written in the linear track on the magnetic tape. Also, it is sent to the magnetic head pair 5a, 5b via the FM audio processing circuit 53, the switch circuit 51, and the recording amplifier 50, and is recorded in the deep portion of the magnetic tape.
Here, the magnetic head pair 5a, 5b for FM audio signal is
Magnetic head pair 6a, 6b for video signals (azimuth angle ± 6
Azimuth angle of ± 30 degrees so that a sufficient azimuth angle can be provided to suppress mutual interference. The video signal is frequency-multiplexed with the luminance signal FM-modulated by the video signal processing circuit 57 and the color signal subjected to the low-frequency conversion, and then sent to the magnetic heads 6a and 6b via the recording amplifier 56 to be the surface layer portion of the FM audio signal. Recorded in. In the digital mode, the digital signal input from the terminal 22 is sent to the magnetic heads 5a and 5b via the digital signal processing circuit 54, the switch circuit 51, and the recording amplifier 50 to be recorded on the magnetic tape. Although the signal input to the terminal 22 is a bit-compressed digital signal here, the processing as a VTR is the same even if the signal is not bit-compressed. In the case of digital recording, a recording signal band is wider than in analog recording, so a head having a large azimuth angle is desired in order to suppress mutual interference from adjacent tracks, but in the case of the VHS system, the FM voice head has ± as described above. Since the head has a azimuth angle of 30 degrees, sufficient performance can be ensured even for digital signal recording, and it is advantageous that the number of heads is small in terms of cost and productivity, the head for digital recording is used as the analog voice dedicated head. An example in which Of course, a dedicated head for digital recording may be provided.

Next, the analog / digital mode discrimination during recording will be briefly described. In the present embodiment, it is assumed that the cassette tape is a high-performance magnetic tape capable of recording digital signals. In the VHS standard VTR, there is a standard called S-VHS aiming at high image quality,
The magnetic tape is also VHS tape and S-V with high coercive force Hc.
There is an HS tape. Since digital recording also requires a tape having a high coercive force, a tape having a high coercive force equal to or higher than S-VHS is required. In this embodiment, VHS
Cassette tape (hereinafter referred to as V cassette), S-V
It will be described that three types of cassette tapes for digital recording (hereinafter referred to as D cassettes) are used in addition to HS cassette tapes (hereinafter referred to as S cassettes). Also, due to the performance of the magnetic tape, only VHS recording is possible with the V cassette, and three types of recording are possible with the S cassette and D cassette. Here, discrimination of each cassette is learned by providing a detection hole for discrimination of VHS / S-VHS, and it is assumed that a detection hole for discrimination of D cassette is provided. FIG. 2 shows a schematic diagram of the tape cassette 55. 101 is an S cassette detection hole, and 102 is a newly provided D cassette detection hole. An example of detection using these detection holes is shown in FIG. FIG. 3 shows the cassette 55 and the push switch 1.
It is sectional drawing of 03,104. Push switch 10
Reference numerals 3 and 104 are installed at positions corresponding to the positions of the detection holes 101 and 102 of the cassette 55 when the tape is loaded. When there is a detection hole, it is not pushed like the switch 103, but when there is no detection hole, the switch 1
It is pushed in by the bottom of the cassette like 04. The presence or absence of the detection hole is determined using this switch output.

FIG. 4 shows a flowchart for mode discrimination. When the automatic discrimination mode is selected, the cassette type is discriminated when the recording is instructed by operating the recording button of the operation panel 60. When it is determined that the cassette is the D cassette, it is determined that digital recording is to be performed, the digital signal input is selected by the switch 51, the digital signal processing circuit 54 is activated, and recording is started. The tape speed is LP mode. If the cassette is not the D cassette, the setting of the manual mode switch on the operation panel 60 is confirmed. If digital recording is selected and the S cassette is selected, digital recording is started. If it is a V cassette, recording is not permitted and the operator is warned to that effect.
The warning is given, for example, by ejecting the cassette. Alternatively, a method such as a buzzer or voice, display on the operation panel or display on the monitor screen may be used. In this embodiment, if the D cassette is used, the digital recording can be automatically selected, the changeover switch need not be confirmed, and the operation becomes easy. In addition, as long as the D cassette is used in the automatic mode, only the digital recording is always performed. It is possible to prevent the analog recording and the digital recording from being lost.
Further, when the recording start time used in the current VTR is set in advance and the reserved recording function for starting recording at the set time is applied to the present embodiment, when the reservation setting is completed, the above cassette is set. If the recording is not permitted, a warning is issued at that point.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 shows a block diagram of a reproducing system of the magnetic recording / reproducing apparatus of the present invention. 98, 13, 26 are reproducing head amplifiers, 99 is a linear audio signal processing circuit, 10
0 is a switch circuit, 14 is an LPF, 15 is an FM audio signal processing circuit, 16 and 20 are mute circuits, 18 is a PLL circuit, 19 is a digital signal processing circuit, 32 is a frequency detection and envelope detection circuit, and 27 is an envelope detection circuit. , 28 is a reproducing analog video signal processing circuit, 29 is a synchronizing signal detecting circuit, 30 is an OSD (abbreviation of On Screen Display) circuit for inserting characters and replacing a blue-back screen, and the others are the same as in the embodiment of FIG. Enter the same number with.

The mode discrimination control of this embodiment will be described below. For determination, the following three types of determination means are used. The first means is a type of cassette discriminating means based on the detection hole shown in the discrimination of recording. The second means is means for discriminating the tape speed at the time of recording. In this embodiment, the CTL signal recorded at the lower end of the tape reproduced by the CTL head 9 and the FG signal (CFG) of the capstan motor 11 are used. It is determined by the frequency ratio or the cycle ratio. The discrimination processing is performed by the arithmetic processing of the microcomputer in the servo system 25, but in order to explain the concrete operation thereof, the discrimination processing will be described by using an example constituted by a digital circuit. FIG. 6 shows a block diagram of an embodiment of the discrimination circuit. A counter 111 uses the FG signal as a clock and is reset by a CTL signal. 1
A latch circuit 13 latches with a CTL signal. 11
Reference numeral 2 is a delay circuit for resetting the counter after latching. Reference numerals 114 to 116 are comparison circuits for comparing the latched count data with a predetermined value, and 117 is an encoding circuit for generating a discrimination signal using the output of the comparison circuit. The detection operation according to this embodiment will be described with reference to the waveform chart of FIG. The frequency of the FG signal is proportional to the rotation frequency of the capstan motor, and the transfer amount of the magnetic tape is proportional to the FG signal. The CTL signal is recorded at a cycle of one frame (rotation cycle of the cylinder 1), but the frequency of the FG signal and the CTL signal or the ratio of the cycle is constant regardless of the tape transfer speed. This ratio becomes smaller as the tape transfer speed becomes smaller in the long-time recording mode. For example, if the ratio of the FG signal to the CTL signal is 18 in the standard speed mode, it becomes 9 in the double mode and 6 in the triple mode. The comparator circuit 11 compares the counter value of the FG counter which is reset by the CTL signal.
The tape speed at the time of recording can be discriminated by comparing with the above values in 4 to 116. The third means is a means for discriminating the type of the reproduced signal, and in FIG. 5, the means for discriminating the digital signal is a PLL for detecting the clock signal component of the reproduced signal.
The synchronous detection method using is shown as an example. Alternatively, it is also possible to detect a signal that can be determined to be meaningful as a digital signal in the digital signal processing, such as a synchronization signal.

The operation of this embodiment will be described below with reference to the flowchart of FIG. When the reproduction button on the operation panel 60 is pressed and a reproduction instruction is given, the cassette is first discriminated. If it is determined that the cassette is a D cassette, it is highly likely that the recording is digital recording, so the reproduction mode is set to the digital mode. The playback speed is set to LP mode. When the reproduction is started and the tracking control is completed, the above digital signal detection is performed, and if the digital recording is confirmed by the clock or the synchronization signal, the digital reproduction is continued. If no digital signal is detected, there is a possibility of analog recording. Therefore, speed discrimination processing is performed, and depending on the detection result, SP, LP or EP mode is set and analog reproduction is performed. If the cassette is determined to be the S cassette, the speed is initially set to the SP mode, reproduction is started, and then the speed is determined. In the LP mode, there is a possibility of digital recording, so digital reproduction is performed and processing is performed according to the procedure shown below. SP or E
If it is determined to be the P mode, the analog recording is performed, and therefore the analog reproduction is performed. If it is determined to be a V cassette, analog reproduction is immediately performed. In this embodiment, the most probable reproduction mode and the tape speed are set by using the cassette detection hole, so that it is possible to shorten the time from the recording instruction until the reproduction mode actually coincides and the image output is started.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 9 shows a block diagram of the recording system of this embodiment. In this embodiment, a VTR of the current VHS system which does not perform digital recording / reproducing is provided with a digital recording detecting means, and has a configuration in which the digital recording / reproducing process is removed from the previous embodiment. The reproducing system is also the same, and has a configuration in which digital processing is removed from FIG. 5 of the previous embodiment, but the details are omitted. The operation of this embodiment will be described below. FIG. 10 shows a control flow at the time of recording. At the time of recording, the cassette is discriminated when a recording instruction is given, and when discriminating as the D cassette, recording is not permitted and the cassette is ejected. D
If it is not a cassette, recording is permitted. When recording on a tape that has already been recorded, or when newly recording on a recorded portion, the user generally reproduces the tape and confirms the contents before recording, but in the case of an analog dedicated machine, it is digital. Even if a signal is recorded, the image cannot be confirmed and the digital signal may be erroneously erased by mistakenly recognizing it as an unrecorded tape and overwriting it. As a result, it is possible to prevent erroneous erasing by overwriting the analog signal on the tape of the D cassette, which is highly likely to be digitally recorded. However, analog recording on the D cassette is not completely prohibited, and recording is possible if this automatic discrimination processing is turned off.

Next, another embodiment of the present invention will be described. This embodiment is similar to the previous embodiment only in the current VHS system, but the cassette detection mechanism is omitted in order to reduce the number of parts and cost, and the cassette detection hole detection circuit 58 of the embodiment of FIG. 9 is used. It becomes the deleted configuration. The operation of this embodiment is shown in FIG.
This will be described using 1. When receiving the recording instruction, the reproducing operation is performed prior to the recording. If the CTL signal is not detected here, it is determined that there is no recording signal, so the reproduction process is terminated and the recording operation is started. If the CTL signal is detected, it means that the tape has already been recorded, and therefore the speed is determined. If the speed is SP or EP mode, the recording is permitted because it is analog recording and is conventional overwriting. In the LP mode, there is a high possibility of digital recording, and it is highly possible that the user cannot recognize that it is a digitally recorded tape (because it is an analog-only machine), so recording is not permitted. Eject the tape. Further, another control flow is shown in FIG. Here, when the recording is not permitted and the tape is ejected, the recording is permitted by inserting the tape again. Therefore, if you want to make analog recording on the D cassette, or if you want to overwrite with the knowledge that the digital signal may be recorded but it will be erased, you do not perform the operation to switch the automatic discrimination mode on / off. You can do more. Note that this is
It can also be applied to a zero flow.

[0018]

As described above, according to the present invention,
In an analog / digital mixed VTR that records and reproduces a digital signal while maintaining compatibility with the VHS standard VTR,
A mode is provided to automatically determine the type of tape by determining the type of tape. During recording operation, a means to detect the type of cassette tape by the presence or absence of a detection hole is used for digital recording. By selecting, the operation of setting the input signal can be omitted. Further, since only digital signals are recorded on the digital tape, it can be distinguished from the analog recording tape and the user can easily manage the tape. At the time of playback, the method that is most likely to be recorded according to the detection result of the cassette, for example, in the case of a digital cassette, the digital method is initialized to shorten the time from the playback instruction to the actual start of image output. can do. In the case of the analog type dedicated machine, the reproducing operation is performed prior to the recording, and the recording is prohibited when the digital signal is detected by the means for detecting the presence or absence of the digital type signal, whereby the erroneous erasure due to the overwriting can be prevented.

[0019]

[Brief description of drawings]

FIG. 1 is a block diagram of a recording system of a VTR showing an embodiment of the present invention.

FIG. 2 is a schematic diagram of a cassette tape used in an example of the present invention.

FIG. 3 is an explanatory view of the principle of cassette discrimination.

FIG. 4 is a control flow chart during recording according to the present invention.

FIG. 5 is a block diagram of a VTR reproduction system showing an embodiment of the present invention.

FIG. 6 is a configuration diagram of an embodiment of tape speed detection.

FIG. 7 is a waveform diagram for explaining an operation of tape speed detection.

FIG. 8 is a control flow chart during reproduction according to the present invention.

FIG. 9 is a block diagram of a VTR showing another embodiment of the present invention.

FIG. 10 is a control flow chart during recording according to the present invention.

FIG. 11 is a control flow chart during recording according to the present invention.

FIG. 12 is a control flow chart during recording according to the present invention.

[Explanation of symbols]

 19, 54 ... Digital signal processing circuit, 15, 53 ... FM audio signal processing circuit, 28, 58 ... Analog video signal processing circuit, 32, 45 ... Frequency detection and envelope detection circuit, 25 ... Servo system control circuit, 34 ... Tuner and MPEG decoder circuit, 18 ... PLL circuit, 68 ... MPEG decoder circuit 5a, 5b ... FM audio head 55 ... Cassette tape 101, 102 ... Tape discrimination detection hole

Front page continued (72) Inventor Hiroyuki Torii 1410 Inada, Hitachinaka City, Ibaraki Prefecture Personal Media Equipment Division, Hitachi, Ltd. Media System Development Headquarters (72) Inventor Katsuyuki Watanabe 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi Ltd. Multimedia System Development Headquarters

Claims (9)

[Claims] 1. A helical scan type magnetic recording / reproducing apparatus using a cassette tape, comprising: first recording / reproducing means for recording / reproducing an analog signal; and second recording / reproducing means for recording / reproducing a digital signal. A switching means for switching between the first recording / reproducing means and the second recording / reproducing means, and a means for discriminating at least one of the type of the magnetic tape or the type of the recording signal are provided, and the discrimination result of the discriminating means is provided. According to the first recording / reproducing means and the second
And a magnetic recording / reproducing device. 2. A helical scan type magnetic recording / reproducing apparatus using a cassette tape, comprising: first recording / reproducing means for recording / reproducing an analog signal; and second recording / reproducing means for recording / reproducing a digital signal. Means for selecting the first recording / reproducing means and the second recording / reproducing means, a switching means for switching the first recording / reproducing means and the second recording / reproducing means, a magnetic tape type, or a recording signal. And a means for discriminating at least one of the types, and the permission of the recording operation is controlled by the discrimination result of the discriminating means. 3. A magnetic recording / reproducing apparatus according to claim 2, further comprising means for disabling a recording operation and issuing a warning. 4. A magnetic recording / reproducing apparatus according to claim 3, wherein the means for issuing a warning is means for ejecting a cassette tape. 5. A helical scan type magnetic recording / reproducing apparatus using a cassette tape, comprising: first recording / reproducing means for recording / reproducing an analog signal; and second recording / reproducing means for recording / reproducing a digital signal. The switching means for switching between the first recording / reproducing means and the second recording / reproducing means, and means for discriminating at least one of the type of the magnetic tape or the type of the recording signal are provided, and the tape speed at the start of reproduction A magnetic recording / reproducing apparatus characterized in that the initial setting is controlled by the discrimination result of the discriminating means. 6. The magnetic device according to claim 1, wherein the means for detecting the type of the magnetic tape is a means for detecting the presence or absence of a detection hole provided in the cassette tape. Recording / playback device. 7. A helical scan type magnetic recording / reproducing apparatus for recording or reproducing an analog signal, wherein means for detecting the type of magnetic tape is provided, and permission of recording operation is controlled by detecting the type of magnetic tape. And a magnetic recording and reproducing device. 8. A helical scan type magnetic recording / reproducing apparatus for recording or reproducing an analog signal, means for reproducing a tape prior to recording, means for detecting the presence or absence of a reproduced signal, and means for discriminating the type of the reproduced signal. A magnetic recording / reproducing apparatus which is provided with, and which does not permit recording unless the reproduced signal is detected and the reproduced signal is a signal of an analog recording / reproducing system. 9. A magnetic recording / reproducing apparatus according to claim 8, wherein the means for discriminating the type of the reproduced signal is performed by discriminating the tape speed.