JPH01311465A - Recording or reproducing device - Google Patents

Abstract

PURPOSE:To prevent the misconception of record/nonrecord by reproducing the outside of a recording area of a recording medium, forming a reference signal, comparing a regenerative signal level from the recording area with the reference signal and deciding whether or not a record has already been finished. CONSTITUTION:A magnetic disk 54 is detected in its loading by a system controller (SC) 50 so as to rotate a motor 56 and then to move a magnetic head 54 into a reference position (nonrecording area). A level of its regenerative signal in envelope size as added by a prescribed noise margin is compared with a max. noise level which is separately set up, and a smaller one is taken for the noise level of the disk 52 as the criterion of record/nonrecord. The noise level in the reference position is detected by the SC 50, and a Ch1-head is moved to an absolute position of a track as indicated by a track access counter, and the envelope size of its output is detected to be compared with the noise level, and when it is smaller than the noise level, nonrecord is registered to a T-table. When it is larger, the head is moved to a position where the regenerative signal level becomes max., and its displacement is recorded to the T-table.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording or reproducing device, and more specifically to a device having video and audio recording or reproducing functions.

[Conventional technology]

Conventionally, in this type of recording or reproducing device, when a magnetic disk as a recording medium is loaded, the recorded contents of the magnetic disk are searched, stored in the memory as a data table, and thereafter, recording is performed according to the data table. - A configuration for controlling playback operations has been proposed.

[Problem to be solved by the invention]

However, in conventional devices, the determination of whether a magnetic disk is recorded or unrecorded in compliance with the still video standard is determined based on whether the playback signal level is above a certain dark value level, so there is a possibility of misjudgment. Furthermore, recording/non-recording has been determined at the position where the reproduced signal level is maximum, so the purpose of the present invention is to present a main determination device.

[Means to solve the problem]

The recording or reproducing device according to the present invention includes a reference signal forming means for reproducing outside the recording area of a loaded recording medium and forming a reference signal for recording/non-recording discrimination, and a reference signal forming means for reproducing outside the recording area of the loaded recording medium, and A determining means is provided that compares the reproduction signal level with the reference signal and determines whether or not recording has been completed.

[Effect]

The above reference signal is a signal based on the noise level of the recording medium, and therefore, when determining recording/non-recording using a fixed darkness value, the recording medium with a low recording level or which would be judged as unrecorded. Even in this recording area, it can be determined that there is recording as long as the reference signal is used as a comparison value.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings. 1st A
The figure shows a block diagram of a recording system according to an embodiment of the present invention, and FIG. 1B shows a block diagram of a reproduction system.

The recording system shown in FIG. 1A will be explained. When recording a video signal, the system controller (hereinafter referred to as SC) 40 switches the switch 20 to the video Cal side, and switches the switch group 4
In response to the operation of the video signal recording switch 4, the head drive circuit 30 moves the magnetic head 31 to a designated trunk position on the magnetic disk 32. When the movement of the magnetic head 31 is completed, the SC 40 instructs the video recording circuit 10 to capture the input video signal for a certain period of time. The video recording circuit 10 performs a known video recording process, and its output is as follows:
The signal is applied to the magnetic head 31 via the pre-emphasis circuit 12, the switch 20 and the FM modulation circuit 22, and is recorded on the magnetic disk 32.

When recording an audio signal, the input audio signal is subjected to noise reduction processing by the encoder 13 and digitized by the A/D converter 14 under sampling pulses from the oscillator 38. When the 5C 40 receives an instruction to start audio recording from the switch group 44, it instructs the address counter 24 to start the A/D converter 14 at a rate corresponding to the audio signal time axis compression rate selected by the switch group 44. The output data is written into the audio memory 15. If the amount of audio signals stored in the audio memory 15 exceeds the recording amount of one track on the magnetic disk 32, or if the still video for the audio signal being recorded is switched, a request to move to another track or a temporary recording operation is made. When a stop request is made,
5C40 moves the magnetic head 31 to a track on the magnetic disk 32 where no signal is recorded (hereinafter referred to as an empty track), and then reads the oscillator 3 from the audio memory 15.
The stored data is read out according to the address signal output by the address counter 26 in response to the oscillation pulse of
The A converter 16 converts it into an analog signal. In addition, D
The /A converter 16 outputs a D/A converter according to the oscillation pulse of the oscillator 39.
Perform the conversion.

Adder 17 adds a control code generated by control code generation circuit 28 and a flag signal generated by flag generation circuit 29 to the time-base compressed audio signal from D/A converter 16. The output of the adder 17 is
The signal is applied to the magnetic head 31 via the pre-emphasis circuit 18, the switch 20 and the FM modulation circuit 22, and is recorded on the magnetic disk 32.

300 is an In signal generation circuit that performs DPSK modulation with a period of 2H on the 10 signals output from the SC 40 in synchronization with the horizontal and vertical synchronization signals separated from the synchronization separation circuit 301. The circuit 300 is reset by a vertical synchronization signal and includes a counter 302 that counts horizontal synchronization signals.
and modulates the ID signal in synchronization with the output of the circuit.

The audio signal is stored in the audio memory 15, and the audio signal is stored on the magnetic disk 32.
The recording operation continues until a voice recording stop request is issued or there are no recordable free tracks on the magnetic disk 32.

Next, the reproduction operation shown in FIG. 1B will be explained. Note that the display device 4
3 and switch group 44 are also used as a recording system. Video and audio are recorded on the magnetic disk 52 as described above. The SC 50 uses a head drive circuit 96 to position the magnetic head 54 on a designated track on the magnetic disk 52. The magnetic disk 52 is rotated at a predetermined speed by a known servo mechanism. The output of the magnetic head 54 is amplified by a reproduction amplifier 59 and applied to an FM demodulation circuit 60.

When the reproduction signal is a video signal, the output of the FM demodulation circuit 60 is applied to a de-emphasis circuit 62 with non-linear characteristics, and the output of the de-emphasis circuit 62 is reproduced by a video reproduction circuit 66. The synchronization separation circuit 94 separates a synchronization signal from the output of the reproduction circuit 66 and applies it to the SC 50.

When the reproduced signal is an audio signal, the output of the FM demodulation circuit 60 is applied to a de-emphasis circuit 6-8 with linear characteristics, and the output of the de-emphasis circuit 68 is applied to an A/D converter 70, an audio memory 72 and a de-emphasis circuit 6-8. The signal is applied to a time base expansion circuit consisting of a /A converter 74, and is also applied to a flag detection circuit 78 and a control code detection circuit 80. Flag detection circuit 78 and control code detection circuit 8
0 detects a flag signal and a control code, respectively, and applies them to SC50. When the timing signal generation circuit 86 confirms the detection of the flag and control code, it instructs the address counter 82 to
The output of the /D converter 70 is sequentially written into the audio memory 72. Note that the A/D converter 70 performs A/D conversion according to the output pulse of the oscillator 90. scso applies audio time axis compression rate data included in the detected control code to the address counter 84. Thereby, the data stored in the audio memory 72 is sequentially read out at a speed according to the audio time axis compression ratio data. The output data of the audio memory 72 is converted into an analog signal by a D/A converter 74 operating under an oscillation pulse from an oscillator 92, and is subjected to decoding and noise reduction processing by a decoder 76.

The scs o constantly monitors the address counters 82 and 84, and when the storage capacity of the audio memory 72 becomes low, it reproduces the recording signal of the track specified by the control code, and updates the current data storage location of the audio memory 72. Store the playback signal in the next position.

The above operations are repeated until a stop switch of the switch group 44 issues a request to stop the playback operation, or a flag added to the recorded audio signal on the magnetic disk 52 indicates the end of the audio sequence.

200 is the DP included in the signal reproduced from the head 54
10 that demodulates the SK modulated signal and outputs it to the SC50
This is a signal judgment circuit. The circuit 200 is the synchronous separation circuit 9
2 depending on horizontal and vertical synchronization signals separated by 4
Performs DPSK demodulation with a period of H. Determination circuit 200 includes a counter 201 similar to circuit 302 of FIG. 1A.

Next, the operation of creating a data table showing the recorded content of the magnetic disk 52 and the procedure for reproducing an audio sequence in the recording/reproducing apparatus having the above configuration will be explained. FIG. 2 shows the flowchart. In this embodiment, it is assumed that when the magnetic disk 52 is not loaded, the magnetic head 54 is located at a reference position further outward from the first track, which is the home position.

FIG. 4A shows a case where an audio signal is recorded on a trunk formed on a magnetic disk, that is, the formant of an audio track. In the audio track, one trunk is divided into four sectors 5t-54, and the format of each sector is as shown in FIG. 4B. In one sector, the start signal of the audio sector is recorded as a start flag SF at the start position, and then the time axis compression ratio of the audio signal and the video signal track address corresponding to the audio signal are recorded as a control code. If the audio signal is recorded continuously over multiple tracks,
The track address at which audio recording starts and the recording trunk address for the next audio signal are recorded. Furthermore, when continuous audio signals are recorded on a plurality of tracks, this is considered to be one group, and hereinafter this will be referred to as one audio sequence. Also, if the recording of the audio signal is completed with only a single track, this
Let's call it a sequence.

First, the data table created in this embodiment will be briefly explained. In this embodiment, there are a data table (hereinafter referred to as T table) in which data of each track is registered, and a table (hereinafter referred to as T table) in which data related to audio sequences is registered.
The format of the T table is shown in Table 1, and the ° format of the S table is shown in Table 2. However, in Table 1, the first data is the 8-bit data related to the signal recorded on the track.・It is data, b,
is a flag indicating the presence or absence of recording, b is an audio/video discrimination flag, b, ~ b0 are optional data, and in the case of a video track, b is a recording signal abnormality flag, and b4 indicates the presence or absence of IO data. b is a field/frame discrimination flag, b2 is a frame inner/outside discrimination flag indicating whether it is on the outer or inner circumference in the case of a frame video, and bl is an audio support flag indicating whether or not there is reference from an audio track. ,
bo indicates the audio sequence head corresponding flag, and in the case of an audio track, .about.b0 indicates the corresponding video track number. The second data in Table 1 is 8-bit data regarding the amount of displacement from the absolute position to the optimal playback position, and S7 is the displacement direction;
B6~B.

indicates the amount of displacement. The data in Table 2 is 8-bit data indicating the audio playback order and the audio sequence group, where bl is the sequence start flag, b,
is the sequence end flag, b.

~b0 indicates the audio track number. The audio is sequentially played back in this storage order.

FIG. 2(e) shows a procedure for obtaining a reference signal for recording/non-recording determination. When the magnetic disk 54 is loaded, the 5C50 detects this and rotates the motor 56 at a predetermined speed. When a servo clock signal indicating stable rotation of the motor 56 is received from a servo circuit (not shown), the magnetic head 54 is moved to the reference position and the signal at that position is reproduced (S
47). In the case of the still video standard, this reference position may be the 0 or 51 track on which recording is not performed, or the outer circumference side of the 0 track. In short, any position that is not recorded is sufficient. The level obtained by adding a predetermined noise margin to the size of the envelope of this reproduced signal is compared with a separately preset maximum noise level, and the smaller one is set as the noise level of the magnetic disk 52 and is set as the noise level of the magnetic disk 52. This is used as the recording criterion (S4B, 49.50). Note that the value obtained by adding a predetermined noise margin to the detection envelope level may be used as the disk noise level without comparing it with the maximum noise level, but the judgment accuracy can be improved by performing the above comparison. will improve.

The magnetic head 54 also has two adjacent tracks so that two adjacent tracks can be played back simultaneously without moving the magnetic head 54.
! It is formed by integrating the ljl magnetic head. Hereinafter, the outer magnetic head will be referred to as channel 1 (chi), and the inner magnetic head will be referred to as channel 2 (ch 2 ).

The SC 50 performs processing as shown in FIG. 2(a).

That is, the noise level at the reference position of the magnetic disk 52 is detected (S1), and the track access counter is initialized (S2). The track access counter indicates the magnetic disk 52 being accessed by the chi head.
Indicates track position above. The 5C50 uses the chi head as the head in use (S3) and moves the chi head to the absolute position of the track indicated by the track access counter (mechanical absolute track position from the reference position) (S4).
), the size of the envelope of the output of the chi head is detected (S5). The 5C50 compares the detected envelope level with the noise level (S6), and if it is smaller than the noise level, registers it as unrecorded in the T table (S7), and if it is larger than the noise level, performs the hill climbing method. The playback head is moved to the position where the playback signal level is maximum (optimum playback position), and the presence of recording and the amount of displacement from the absolute track position are registered in the T table (S8).
.

5C50 instructs the flag detection circuit 78 and control code detection circuit 80 to reproduce the signal at the position of the flag and audio control code that should be added to the audio signal from the signal of the portion corresponding to sector #1 of the reproduction track. (S9), and it is determined from the playback result whether or not the track has an audio signal recorded thereon (SIO). If it is determined to be an audio track, as shown in Figure 2 (the flow moves to BL and the flags and control codes of each sector #1 to #3 are played back), it is determined again whether it is an audio track or not. (S12). If it is determined that it is an audio track, then a determination is made based on the playback flag (S13). In other words, the flag added to sector #0 is type 4 (
If the track is unrecorded (indicating unrecorded), it is registered as an unrecorded track in the T table (S7), and sector IIO is type 1 (indicating the start of a sequence) or type 2 (indicating sequence continuation) and sectors #1 to If the type 2 flag or sectors #1 to 3 are switched from type 2 to type 4 in step 3, the playback control code is checked to determine whether it is the first track of the sequence (S14).

If it is the first track of the sequence, register the fact that it is an audio track in the T table, and if there is a corresponding video track, its number, and then check whether there is a duplicate track number to be registered in the S table. If there is a duplicate, the registration is deleted (515), and the trunk number, the fact that the track is the beginning of the sequence, and the track number following the track are newly registered (516). If it is not the first track of the sequence,
After registering that it is an audio track and the corresponding video track number in the T table, search the S table for the sequence position to which the audio track belongs and its track number, and then search the S table for the sequence position to which the audio track belongs and its track number, and check that the audio track should be played within that sequence. Add additional registration to the location.

If the sequence to which the audio track belongs is not found, a new sequence is registered (517).

If the playback flag is type 3 (indicating the end of the sequence) in any of sectors #θ to #3 (S13), the played audio control code is checked to determine whether it is the first track of the sequence (318). ).

In the case of the first track of the sequence (51B), after registering the fact that it is an audio track and the corresponding video track number in the T table, check whether this audio trunk number has already been registered in the S table, and check if it has been registered. If it is deleted from the S table (519), then the track number is registered along with the fact that the sequence is completed with one new track (520).If it is not the first track of the sequence (51B), the audio track is added to the T table. After registering the information and the corresponding video track number,
After searching the table for the position of the audio sequence to which the audio track belongs and its position within the audio sequence,
Registers that the track is the ending track of the audio sequence. However, if the audio sequence to which it should belong is not found from the data table, an additional audio sequence is registered, and if the audio sequence to which it belongs is found but the corresponding track number is not found within that sequence. If so, the fact that the sequence ends at that track and the track number are registered in the end position of that sequence in the S table.

In addition, when it is determined that the track is not a track on which an audio signal is recorded (SIO), the output of the oscillator 90 provided in the 5C50 is used to determine whether the recorded signal is a video signal or not. The ID data reproduction timeout timer, which is a counting counter, is started (S24), and the determination circuit 200 is instructed to reproduce the io data (S25). The reproduction of [0 data in the video reproduction circuit 66 is performed in synchronization with the synchronization signal of the reproduced video signal, so when the audio signal is being reproduced, there is no equivalent to the synchronization signal of the video signal, and the ID data is Unable to play.

The 5C50 waits for the ID reproduction end signal from the determination circuit 200 and monitors the ID reproduction timeout timer (S26, 27) - If the 10 reproduction timeout timer times out before the 010 reproduction (S2
7) Since it is determined that the signal is not a video signal, the process moves to the audio signal processing sequence again to confirm whether it is an audio track (S27→511). If the playback of In ends before the timeout (S27),
Since it is a video signal, it is necessary to determine whether it is the outer track of the frame video from the 10 reproduced data (528)
If it is not an outer track, it is registered as a field recording track in the T table (338), and if it is an outer track, it is registered in the T table as a field recording track (S29).

The playback timeout timer may be a counter outside the SC 50, for example, a counter 201 within the determination circuit 200 that counts the synchronization signal of the video signal. In short, any circuit that counts the number of synchronization signals within a predetermined period of time may be used.

Then, switch the playback head in use to the chZ side (S3
0), 5C50 instructs the flag detection circuit 78 and control code detection circuit 80 to reproduce the flag and audio control code added to the audio signal from the reproduction signal corresponding to sector #1 531) ,
Based on the result, it is determined whether the signal is an audio signal or not (S32).

If it is determined to be an audio track (S32), ah 1
Change the registration of the frame video outer circumferential side performed for the track corresponding to the head to the registered video, and switch the used head to chl (S3B), If it is determined that it is not an audio track (S32), 10 Start the playback timeout timer (S33),
Instruct the video reproduction circuit 66 to reproduce 10 (534)
, waits for the end of playback (S35.36). If a timeout occurs before the end of ID playback (S36), the frame video outer peripheral side registration performed for the track corresponding to ch1 head is changed to field video registration, and the used head is switched to chi (S3B). If the reproduction of the ID ends before the timeout (S35), it is checked from the reproduced IO data whether it is the inner track of the frame video (S37).

If it is not on the inner side of the frame (S37), the registration on the outer side of the frame video performed for the trunk corresponding to the CH 1 head is changed to the registration of field video, and the used head is switched to CH (S3B). If it is determined that the frame is on the inner side, the frame/video inner side is registered in the track portion corresponding to the ch2 head of the T table (S39).

Next, the track access counter is incremented according to the channel of the head used (840 to 542).
, determines whether access to all tracks is complete (S43
). If there are tracks that you have not accessed yet,
The sequence from S30 is repeated until all tracks are accessed. Then, the registered contents of the data table are searched, and the data table is operated on missing tracks and abnormally registered tracks in the audio sequence (S44).
), counts the number of unrecorded tracks from the data table (545), switches the playback head in use to chl, and ends the search operation for the recorded contents of all tracks.

The audio sequence loss processing (S44) will be described in detail with reference to FIG. The presence or absence of an audio trunk is checked using the T-table created by the search operations up to Sl-S43 (S51). If no audio track exists, the T-table and S-table are not operated; if an audio trunk exists, To do this, the access counter of the S table is initialized (552), and the voice trunk number is read from the table indicated by the access counter (553). It is checked whether the read track number actually exists (554), and if it exists, the data of that track is read from the T table (S
55). Then, it is determined whether it is unrecorded or not (556),
If it has been recorded, it is determined whether it is audio or not (S5
6-1). If it is audio, check whether it is the beginning of the audio sequence by referring to the data in the S table (S57), if it is the beginning, check whether it is the beginning data of the S table (S61), and if it is not the beginning of the S table, check whether it is the beginning of the audio sequence (S57). 562), and if it is determined that it is not the end track, a flag indicating the end of the sequence is set for that data. (S63).

Next, the presence or absence of a corresponding video track is checked from the data read from the T table (S64), and if a corresponding video exists, the first track of the audio sequence corresponds to that video trunk data in the T table. A flag indicating this is set (S65). If it is not the beginning of the audio sequence (S57), it is determined whether it is the last track of the audio sequence (55B), and if it is not the last track, the track following the currently referenced track in that sequence is selected. If it does not exist, a flag indicating the end of the sequence is set in the currently referenced data in the S table (S60).

Also, if it is determined that it is not an audio track (S56-
1) The corresponding data in the T table is re-registered as an abnormal track (S69). If the track number registered in the S table does not exist (S54)
, when it is determined that the track is an unrecorded track (S56),
Examine the registered data in the S table and perform error handling. S
It is checked whether the registered data in the table is the first trunk of the audio sequence (S70), and if it is the first track, the presence or absence of the next registered data after that data is checked (S74), and if there is, the data is changed to the next data. A flag for the first track of the sequence is set (S75). If the registered data in the S table is not the beginning of the sequence (Sho), check whether it is the last track of the audio sequence (S71);
Set the flag of the last track of the audio sequence to the data before that data (S73), If it is not the last track of the audio sequence (371), check whether it is the last track of the registered data in the S table (S?2), In the last case, a flag for the last track of the audio sequence is set in the registered data before that data (573).

Then, use the S table to delete the registered data5.
76) Decrement the number of audio tracks, that is, the number registered in the S table (S77). S table access/
The counter is incremented 567) and a check is made to see if the S table search has been completed 568), and the sequence from S53 onward is repeated until the search is completed.

As described above, in this embodiment, the data table created by the first search operation is checked in the second search to avoid any inconvenience during actual reproduction and recording operations. Furthermore, if discrimination between audio and video is performed using the synchronization signal added to the video signal, an audio signal with a sine wave of a specific frequency, for example, a 100 Hz sine wave at a signal compression rate of 1/640, will be detected. When attempting to distinguish it, the problem arises that it corresponds to a frequency approximately four times that of the horizontal synchronizing signal and is mistakenly recognized as a video signal by the video signal reproducing circuit. ) of 8
9-SIO, as shown in S24-S27, if the track has an audio signal recorded, it is determined whether there is a flag or control code recorded along with the audio signal, and the number of synchronization signals in a predetermined time is determined. Since it has already been determined, it can be determined more reliably.

Table 1 Track Table This embodiment also prevents misidentification of recorded/unrecorded data due to variations in noise level among magnetic disks.
Furthermore, it is possible to prevent misidentification of specific audio recordings. Furthermore, since the unrecorded status is determined based on the absolute trunk position, the time required to move the head to the optimum signal reproduction position can be saved. Since the position where each track can be optimally reproduced is stored as the amount of displacement from the absolute track position of that track, the access time for each track can be effectively shortened.

Table 2 Sequence Table It goes without saying that the present invention is applicable to both recording-only devices and playback-only devices. In this embodiment, a magnetic disk is used as an example of the recording medium, but the present invention is not limited to this, and other types of media such as an optical disk or a magneto-optical disk may be used.

〔Effect of the invention〕

As can be easily understood from the above explanation, according to the present invention, it is possible to prevent misidentification of recording/non-recording due to variations in noise level among recording media, and it is also possible to prevent misidentification of signal recording of a specific frequency. can.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1A is a block diagram of a recording system according to an embodiment of the present invention, FIG. 1B is a block diagram of a reproduction system thereof, and FIG.
1-(e) are flowcharts of table creation, Figure 3 (
al to (C) are flowcharts of deletion processing, FIG. 4A shows the format of the audio track, and FIG. 4B shows the format of the sector.

Claims (1)

[Claims] A reference signal forming means for reproducing outside the recording area of the loaded recording medium and forming a reference signal for recording/non-recording discrimination, and comparing the reproduction signal level from the recording area of the recording medium with the reference signal. and determining means for determining whether recording has been completed or not.