JP3178262B2 - Magnetic recording / reproducing device - Google Patents

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 discriminating whether a video signal is an even field or an odd field (hereinafter referred to as field discrimination). .

[0002]

2. Description of the Related Art In recent years, there has been a great demand in the market for magnetic recording / reproducing apparatuses to improve the editing accuracy and simplify the editing operation, and various methods have conventionally been employed. By reading out bit information indicating a field number written on a scanning line having a retrace interval of a video signal input to the device, or conversely, writing and magnetic recording by a magnetic recording / reproducing device and reading it out again during reproduction, There is a method in which the recording / reproducing apparatus can recognize a video signal which is input or reproduced by the recording / reproducing apparatus in units of fields, thereby realizing accurate editing in units of fields and improving editing accuracy. Here, the number of the scanning line in the video signal retrace interval on which the bit information indicating the field number is written is determined by a standard, and the magnetic recording / reproducing apparatus accurately recognizes the scanning line and reads it. Or writing. Further, the scanning line number makes one cycle in one frame composed of the odd field and the even field of the video signal (NTSC).
Therefore, in order to correctly recognize the scanning line number, the odd-numbered field must be recognized first, and the scanning line number starting from the odd-numbered field must be counted. In other words, in order to correctly recognize the scanning line number determined by the standard, and to read or write bit information indicating the field number written on the scanning line, the magnetic recording / reproducing apparatus always performs accurate field discrimination even during special reproduction. It is necessary to do.

The field discriminating block of the conventional magnetic recording / reproducing apparatus will be described below. FIG. 3 is a block diagram showing a configuration of a field discrimination block of a conventional magnetic recording / reproducing apparatus, and FIG. 4 is a waveform diagram showing this field discrimination method.

[0004] The field discrimination mechanism of the conventional field discrimination block will be described below with reference to FIGS. 3 and 4. In FIG. 3, reference numeral 1 denotes a synchronizing signal separating unit that extracts a vertical synchronizing signal and a horizontal synchronizing signal from a video signal and removes an equivalent pulse in a retrace interval. 3 in FIG. 3 is input to the magnetic recording / reproducing apparatus input to the synchronization signal separation unit 1;
Alternatively, the video signal reproduced by the magnetic recording / reproducing device is
Reference numeral 41 denotes an odd field, and reference numeral 46 denotes a waveform near the vertical synchronization signal of the even field. In FIG. 3, reference numeral 13 denotes a V pulse from which the vertical synchronizing signal of the video signal is extracted from the output of the synchronizing signal separating unit 1 and the equivalent pulse is removed.
In FIG. 4, reference numeral 42 denotes an odd field, and reference numeral 47 denotes an even field. In FIG. 3, reference numeral 12 denotes an H pulse which is an output of the synchronizing signal separating unit 1 and is a horizontal synchronizing signal extracted from the video signal 11 and from which an equivalent pulse in a retrace interval has been removed. This shows the appearance of the field. In FIG. 3, reference numeral 2 denotes a pulse generation circuit which, when the H pulse 12 is inputted, generates an HD pulse 21 having a duty of the H pulse of 50%. In FIG. 4, reference numeral 44 denotes an HD pulse of an odd field, and 49 denotes an HD pulse of an even field. FIG.
Reference numeral 3 denotes a latch circuit which reads the H and L levels of another input HD pulse 21 when the input V pulse 13 changes from H level to L level, and then changes the level to V
Hold and output until the pulse 13 changes from H to L.
33 is the output FD pulse. In this conventional field discriminating block, the pulse discriminating circuit 2 and the latch circuit 3 serve as a field discriminating information generating section for outputting information for discriminating even and odd fields in real time. 4 in FIG.
Reference numeral 5 denotes an odd field, and reference numeral 50 denotes an even field FD pulse, that is, field discrimination information. In FIG. 3, reference numeral 4 denotes a determination unit. FD pulse 33
Is input, if the FD pulse 33 is H, it can be determined that the following video field is an odd field, and if it is L, it can be determined as an even field.

More specifically, referring to FIG.
Since the odd field and the even field of the video signal each have 262.5 scanning lines, the HD pulse 4 falls at the falling timing of the V pulse 42 in the odd field.
If 4 is H, the V pulse 47 in the even field is used.
The HD pulse 49 becomes L at the falling timing of. Therefore, the FD pulses 45 and 50 are H in odd fields and L in even fields. In FIG. 3, this FD
By inputting the pulse 33 to the determination unit 4, the determination unit 4
Field discrimination of a video signal can be performed based on H or L of a pulse.

[0006]

However, in the above-described conventional configuration, there is no problem with a normal video signal, but when a video signal at the time of special reproduction of a magnetic recording / reproducing apparatus is input, field discrimination malfunctions. Become. This will be described with reference to FIG. In FIG. 5, reference numeral 51 denotes a video signal during normal reproduction of an odd field, 52 denotes a video signal of an odd field during special reproduction, 53 denotes a V pulse of an odd field during special reproduction, 54 denotes an H pulse of an odd field during special reproduction, and 55
Represents an HD pulse in an odd field during special reproduction, and 56 represents an FD pulse in an odd field during special reproduction.

Similarly, 57 is a video signal during normal reproduction of an even field, 58 is a video signal of an even field during special reproduction, and 59 is a V pulse of an even field during special reproduction.
Reference numeral 10 denotes an H pulse in an even field during special reproduction, 511 denotes an HD pulse in an even field during special reproduction, and 512 denotes an FD pulse in an even field during special reproduction.

As shown by the video signals 52 and 58, in the magnetic recording / reproducing apparatus, at the time of special reproduction, noise occurs due to the deterioration of the reproduction output signal SN near the vertical synchronizing signal, and the vertical shake of the special reproduction screen occurs. A pseudo vertical signal pulse called a V pulse is generally inserted.
On the other hand, the phase (or width) of one field of the pseudo V pulse can be changed by TV so that the vertical synchronization is stabilized. That is, the pseudo V may be inserted at the phases of A and B shown in the even field video signal 58 during the special reproduction. As a result, when a pseudo V pulse is set at the phase of A in the even field video signal 58 by chance, the even field V pulse 59 at special playback falls from H to L at A, and the even field HD pulse at special playback at that time. Since 511 is L, the even field FD pulse 512 at the time of special reproduction is normally L in the odd field and H in the even field as indicated by the solid line. However, when the insertion phase of the pseudo V pulse is set at the timing B in the special reproduction even field video signal 58, the special reproduction even field V pulse 59 at this time is B and H
, And the special field even field HD pulse 511 at that time is H, so that the special playback even field FD pulse 512 remains at the H level as shown by the dotted line, and the discrimination unit 4 in FIG. There was a problem that it became impossible.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic recording / reproducing apparatus having a field discriminating block capable of correctly continuing field discrimination results even during special reproduction.

[0010]

In order to achieve this object, a field discriminating block in a magnetic recording / reproducing apparatus according to the present invention comprises a field discriminating information generator for performing field discrimination in real time except for special reproduction. As it is, and during trick play, the field discriminating information immediately before trick play enters is retained in place of the field discriminating information.Field discriminating information for even-numbered fields, field discriminating information for odd-numbered fields, and trick play for each field from the next field A field discrimination forced switching processing unit that generates the field discrimination information while maintaining the continuity of the field discrimination information before the entry is added between the field discrimination information generation unit and the discrimination unit.

[0011]

With this configuration, the conventional real-time field discrimination information is input to the discrimination unit except for the special reproduction, and the conventional field discrimination result is obtained. During the special reproduction, a malfunction occurs due to the phase of the pseudo V pulse. Instead of the field discrimination information, the field discrimination information immediately before the trick-play is entered is retained. By generating the field discrimination information while maintaining continuity, the field discrimination information that maintains the continuity of the field discrimination is input to the discrimination unit even during the special reproduction, so that the discrimination unit can accurately perform the special reproduction. Field determination can be performed.

[0012]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a field discrimination block of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. FIG. 2 shows generation of field discrimination information of the field discrimination block during special reproduction and its discrimination. It is a waveform diagram shown.

An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 1 denotes a synchronization signal separation unit that extracts a vertical synchronization signal and a horizontal synchronization signal from a video signal and removes an equivalent pulse in a retrace interval. Reference numeral 11 denotes a video signal input to the magnetic recording / reproducing apparatus which is input to the synchronizing signal separating unit 1 or reproduced by the magnetic recording / reproducing apparatus. This is a V pulse extracted from which the equivalent pulse is removed. Reference numeral 13 denotes a horizontal synchronizing signal and an H pulse which are extracted from the video signal 11 by an output of the synchronizing signal separating section 1 and from which equivalent pulses in a retrace interval are removed. Reference numeral 2 denotes a pulse generation circuit that, when the H pulse 13 is input, sets the duty of the H pulse to 50%
The generated HD pulse 21 is generated. Reference numeral 3 denotes a latch circuit which reads the H and L levels of another input HD pulse 21 when the input V pulse 12 changes from H level to L level, and then changes the level from H level to L level. And output. 31 is the output FD pulse. Reference numeral 4 denotes a field discrimination forced switching unit which normally outputs the input FD pulse 31 as it is as the FD 'pulse 41. The S pulse 42 is a pulse for notifying the time of special reproduction.
When the pulse 42 rises from L to H, it is recognized that special reproduction is being performed. Reference numeral 5 denotes a discrimination unit. In this embodiment, the cost is reduced by incorporating the field discrimination forced switching unit 4 and the discrimination unit 5 into a part of the microcomputer 6.

In FIG. 2, reference numeral 21 denotes a video signal at the time of normal reproduction of an odd field, 22 denotes a V pulse of the odd field at the time of special reproduction, 23 denotes an H pulse of the odd field at the time of special reproduction, and 24 denotes an HD pulse of the odd field at the time of special reproduction. , 2
Reference numeral 5 denotes an FD pulse in an odd field during special reproduction.

Similarly, reference numeral 26 denotes a video signal of an even field during normal reproduction, 27 denotes a video signal of an even field during special reproduction, and 28 denotes a V pulse of an even field during special reproduction.
Reference numeral 9 denotes an H pulse of an even field during special reproduction, 210 denotes an HD pulse of an even field during special reproduction, 211 denotes an FD pulse of an even field during special reproduction, and 212 denotes an even field generated by a field discrimination forced switching unit during special reproduction. FD 'pulse.

In this embodiment, the field discriminating information generating section for generating field discriminating information in real time is constituted by the pulse generating circuit 2 and the latch circuit 3, and this field discriminating information generating section is used. explain.

At the time of normal reproduction, since it is as described above with reference to FIGS. 3 and 4 in the conventional example, detailed description is omitted. In FIG.
When a pseudo V pulse having a phase like 27 is inserted into the video signal 26 of the even field at the time of special reproduction, the V pulse at this time falls from H to L at the phase B as shown by 28, and at this time the HD pulse Since 210 is H, the FD pulse 211
Remains at H. As a result, if the FD pulse 211 is input to the discriminating section as it is, the discriminating section always recognizes the field as an odd field, resulting in a malfunction of the result field discriminating block.

Therefore, in FIG. 1, the field discrimination forced switching unit 4 first recognizes the special reproduction by the rising of the S pulse 42 from L to H, and the FD pulse 31 remains unchanged.
The output as the D 'pulse is stopped, and in FIG. 2, if the FD pulse immediately before entering the special reproduction is at the H level, a pulse obtained by inverting the FD pulse 211 at the timing when the V pulse 28 falls from H to L is generated. It is output as the FD 'pulse 212. That is, when the V pulse 28 is B
If the FD pulse 211 at the time of entering special reproduction is H, the FD 'pulse 212 inverts the previous H level to L, regardless of the HD pulse 210 when the L falls at the timing of. Thereafter, this inversion processing is continued at the timing when the V pulses 22 and 28 fall from H to L.

In this way, even if the pseudo V phase of the V pulse 28 changes, only the timing at which the logic of the FD 'pulse 212 changes changes. The discriminator 5, which receives L in the field and receives this FD 'pulse in FIG. 1, can correctly continue the discrimination result even during the special reproduction in the field discrimination.

[0021]

As described above, according to the present invention, the field discrimination switching section is added to the front of the discrimination section in the field discrimination block, whereby the field discrimination of the video signal can be maintained without malfunction even during the special reproduction. A magnetic recording / reproducing apparatus.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a field discrimination block of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a waveform chart for explaining the operation of a field discrimination forced switching unit during special reproduction of a field discrimination block in the embodiment.

FIG. 3 is a block diagram showing a configuration of a field determination block of a conventional magnetic recording / reproducing apparatus.

FIG. 4 is a waveform chart for explaining the operation of a conventional field discrimination block.

FIG. 5 is a waveform chart for explaining the operation of a conventional field discrimination block during special reproduction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Synchronization signal separation part 2 Pulse generation circuit 3 Latch circuit 4 Field discrimination forced switching part 5 Discrimination part 6 Microcomputer

Claims (1)

(57) [Claims] 1. A synchronizing signal separating section for extracting horizontal and vertical synchronizing signals from a video signal being input to or reproduced from a magnetic recording / reproducing device, and a video signal using the horizontal and vertical synchronizing signals. A field discriminating information generating section for generating information for discriminating whether the field is an even field or an odd field, and the field discriminating information of the field discriminating information generating section is passed as it is except for special reproduction of the magnetic recording / reproducing apparatus. Output, and at the time of trick play, the field discriminating information immediately before trick play enters is stored in place of the real-time field discriminating information of the field discriminating information generating section, and even field information and odd field information are provided for each field from the next field. Field discrimination information is sequentially forcibly maintained so that continuity of field discrimination information is maintained. A magnetic recording / reproducing apparatus comprising: a field discrimination forced switching processing section for switching and outputting information; and a field discrimination block comprising a discrimination section for finally performing field discrimination by the output of the field discrimination forced switching section.