JP3029194B2 - Recording and playback 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 recording and reproducing apparatus, and more particularly to an apparatus for recording and reproducing an additional information signal together with a video signal.

[0002]

2. Description of the Related Art Conventionally, recording / reproducing apparatuses such as VTRs which record a time code and various control codes together with a main information signal such as a video signal have been increasing. Hereinafter, in this specification, a VTR in which a video camera is integrally incorporated, that is, a so-called camcorder will be described as an example of this type of device.

FIG. 7 is a diagram showing a configuration example of a conventional camcorder. A time information recording / reproducing device in a camcorder is
Conventionally, as shown in FIG. 7, an output signal of a character (character) information generator 5 based on a time code from a time code generator 6 is obtained from a well-known circuit including an optical system 1, an image sensor 2, a camera signal processing circuit 3, and the like. To the output video signal,
Multiplexed by the adder 4. That is, the time code is recorded in the form of a video signal as character information.
The video signal in which the character information is multiplexed is a recording signal in a signal form suitable for recording in the recorder signal processing circuit 7 together with four kinds of pilot signals (4f) used for tracking control of an audio signal (Audio) four frequency system. After that, the signal is converted into a signal, and is recorded on the magnetic tape 10 as a tape-shaped recording medium by the rotary heads 9-a and 9-b via the amplifier 8 and the head switch 11.

When the above-described signal is reproduced, information at the time of recording by the time code generator 6 is displayed on a part of the video imaged by the optical system as shown in FIG.

Another method of recording the time code is a method of recording on a longitudinal track formed at the end of the tape. Each track is provided with a subcode recording area separately from a main information recording area. There is a method of recording as a subcode in an area.

[0006]

First, when a time code is recorded as character information as a video signal, the time code is superimposed on the video signal, so that it always overlaps with the imaging screen during reproduction. Characters and image screens cannot be separated. Also, at the discretion of the photographer, it is necessary to turn on the operation switch according to the
An OFF setting is required in advance during recording. Furthermore,
Along with this, it has been impossible to know the time information of the portion where the character information indicating the time code is not imposed on the screen.

Further, when recording a time code on a longitudinal track, the relative speed between the fixed head and the tape is low, so that recording of multiplexed information cannot be expected. It was difficult to record such additional information. Further, since it is necessary to provide a fixed head, it is not preferable in that abrasion of the tape and complication of the mechanical portion are caused.

Further, when a time code is recorded as a subcode in a subcode area provided on each track, it is difficult to read the subcode information when the tape is run at a high speed, for example, at the time of forward / reverse search of a VTR. ,
This tendency is more remarkable especially when so-called azimuth recording is performed. Providing a subcode area on each track hinders high-density recording.

Under the above-mentioned background, the present invention provides an apparatus capable of freely multiplexing a character signal representing a date with a video signal and reliably obtaining date information. With the goal.

[0010]

In order to solve the above problems and achieve the object, the present invention provides an image pickup means for generating a video signal, a date generation means for generating date information, and an additional information indicating the date information. Additional information generating means for generating an information signal, recording means for recording the video signal and the additional information signal on a recording medium, reproduction means for reproducing the video signal and the additional information signal from the recording medium, Character signal processing means for generating a character video signal representing the date information based on the additional information signal reproduced by the reproduction means, and multiplexing the character video signal and the reproduction video signal; An operation unit for arbitrarily instructing whether or not to multiplex a character video signal; and the character signal processing unit according to an instruction from the operation unit. Said is constituted by a control means for controlling whether to multiplex the reproduced video signal and the character signal and by.

[Operation] In the present invention, an additional information signal indicating a date is recorded and reproduced together with a video signal, and a character signal generated in accordance with the reproduced additional information signal is arbitrarily multiplexed with the reproduced video signal.

[0012]

Embodiments of the present invention will be described below.

FIG. 1 is a diagram showing a schematic configuration of a camcorder according to an embodiment of the present invention. In FIG. 1, a light beam from a subject (not shown) incident from an optical system 1 forms an image on an image sensor 2. The output of the image sensor 2 is converted into a television signal by a well-known camera signal processing circuit 3.

The time code generator 4 generates a time code (year, month, day, hour, minute, second, etc.) in the form of a digital signal from a circuit using a so-called digital clock similar to the conventional example. This data is a time code relating to the time at the time of imaging or the time counter from the beginning of the tape being used.

The time code is converted into a television signal form by the character generator 5 as necessary, as in the conventional example, and multiplexed with the picked-up television signal. The image pickup television signal output from the camera signal processing circuit 3 and the character signal relating to the time code output from the character generator 5 are combined in an adder 6.

The television signal synthesized by the adder 6 is a VTR
Is converted into a known recording signal according to a predetermined recording format. That is, the audio signal collected by the microphone 16 is FM-modulated by the audio processing circuit 15, and the FM-modulated signal is supplied to the adder 14 together with the four-frequency tracking pilot signal output from the four-frequency generator 13. And the video signal output from the recorder signal processing circuit 7 is synthesized.

The output of the time code generator 4 is supplied to the data encoder 8 together with the codes output from the ID signal generator 9 for identifying various modes according to the operation of the operation switch 26. Using the output of the data encoder 8, the gate circuit 12 switches (amplitude modulates) the signal of the frequency f ₆ generated by the pilot signal 11 (hereinafter referred to as f ₆ signal). The output of the gate circuit 12 is
The signal obtained by trapping the f ₆ component in the signal according to the predetermined recording format is superimposed by the adder 18.

The frequency of the pilot signal is selected so that interference with the frequency of each signal conventionally used in a VTR is minimized. As the frequencies conventionally used, four kinds of pilot signals (100K to 200K) for tracking by a four-frequency system, DTF
Control or pilot signal of a frequency f ₅ used in the multi-channel recording determination of PCM audio (200K～300K) and the chroma low-frequency converted signal (74
3K ± 350K). The time code in the VTR according to the present embodiment can be recorded if it has a band of about 10 KHz, even if the SMPTE time code is supported. Therefore the f ₅ signals the upper limit (about 300K) and chroma low-frequency converted signal limit (approximately 400 K) the frequency took more margin 10K from the f ₆ modulation carrier.

The above-described trap circuit 17 removes a frequency component corresponding to f ₆ from an original recording signal in order to prevent a malfunction. FIG. 2A shows a frequency spectrum layout after the above-described f ₆ multiplexing, and FIG. 2B shows a frequency characteristic diagram of the trap circuit.

The recording signal generated in this manner is amplified by the recording amplifier 19, and is amplified by a frame period 30 to be described later.
Via a switch 24 switched by a PG pulse, two rotary heads 20-a and 20-b having different azimuth angles
Thus, recording is performed while forming recording tracks on the tape.

The rotation of the rotary drum to which the rotary heads 20-a and 20-b are attached is detected by the rotary phase detecting head 22 and the amplifier 23, and the timing circuit 25 outputs the 30 PG pulse at a predetermined timing. Perform delay processing and the like. The 30PG pulse is used by the data encoder circuit 8 as reference timing for generating sync data of a time information array for each track.

FIG. 3 shows a recording track pattern of the VTR of this embodiment. Video signal, FM modulated audio signal, f
A recording signal including a modulation signal of _six signals is alternately recorded in a video recording track area with plus azimuth and minus azimuth. As a modulation signal of the f ₆ signal to record information indicating the shooting time plus azimuth track, it will record the time counter information from the tape end in use minus azimuth track. In the figure, the part indicated by ID is mode data indicating the contents of the time code of each track, and the IDs "01" and "10" correspond to the shooting time and the time information from the end of the tape, respectively. This ID word is arranged at the center of each track, which is advantageous during a search described later. Since the reproduction envelope cannot be obtained over the entire area of the track when the tape runs at high speed, the mode information is arranged at a position close to the information effective for the actual search, thereby increasing the probability of simultaneous reproduction detection.

The ID word can also be used as a check bit for preventing a malfunction in a tape recorded by a device that does not employ the function described in this embodiment. For this purpose, bits are assigned avoiding "11" and "00".

For example, as the information indicating the photographing time, the year, month, day, mode information, time,
Record the minute and second information. As shown in FIG. 4, in addition to the contents described above, clock run-in (32 bits) and sync data (16b
It) is provided at the head of the information, and a CRC (8 bits) for error correction is provided after the information. The month, day, hour, minute,
The code indicating the second, frame and ID is provided with a parity check bit of 1 bit as a maximum of 7 bits, and a total of 8 bits is provided.
Handle as bits. That is, at the time of search, only error detection can be performed using the one-bit parity, and at the time of normal reproduction, error correction can be performed in track units.

By the way, 2 bi in the ID data 7 bit
Table 1 shows an example of mode setting using t.

[0026]

[Table 1]

Next, data detection and search operations during reproduction will be described.

FIG. 5 shows a configuration example of a reproducing system corresponding to the camcorder of FIG. From the tape 21, the rotating head 20-
a, the signal detected at 20-b is the signal of the head drum 1
The switching is performed by the switch 60 at 30PG every 80 degrees rotation, amplified by the head amplifier 61, and supplied to various filters. The drum rotation phase signal detected by the drum rotation detection head 22 is amplified by the amplifier 23 and supplied to the switch 60 and the data decoder 75 by the timing circuit 51 as 30 PG pulses at a predetermined timing. The data decoder 75 receives the azimuth angle ± 30 PG pulse.
Make a determination.

The BPF 66 is a band-pass filter for extracting an audio signal. The BPF 67 is a band-pass filter for extracting a chroma signal, and the HPF 68 is a high-pass filter for extracting a luminance signal. A signal extracted from each of these filters is a recorder. The reproduction signal processing circuit 70 performs a process reverse to that at the time of recording.

The BPF 69 is a band pass filter for extracting an f ₆ signal, and its center frequency, band, and the like are adjusted to the f ₆ signal carrier frequency and sideband. This BPF69
Is converted into a digital signal by a detection circuit 71 and a waveform shaping circuit 72. Further, the digital signal is demodulated by the data decoder 75 into a time code.
At the time of demodulation, the above-mentioned 30PG pulse is used as auxiliary information to detect the start point of clock run-in and to determine the ID.
The azimuth angle is determined for mode determination when data cannot be detected.

The demodulated time code is supplied to the character generator 76 to obtain character information. In the adder 77, the character information is multiplexed with the luminance signal, and then supplied by the NTSC encoder 78, converted into a composite video signal by the encoder 78, and output together with the demodulated audio signal.

The major difference between the apparatus of the present embodiment and the conventional apparatus is that a signal from an operation switch 79 is supplied to a character generator 76 via a system controller / microcomputer (hereinafter referred to as a syscon) 74. It is a point.
By operating the operation switch 79 during playback,
Multiplexing of time code to video information can be switched on / off.
For example, when multiplexing is to be cut off, all output data of the data decoder 75 may be replaced with data corresponding to blanks by the character generator 76 in accordance with an instruction from the system controller 74.

The time code demodulated as described above can be used for retrieval in addition to the above display. That is, since the demodulated data obtained by the data decoder 75 is always supplied to the system controller 74, the demodulated data is compared with the target value of the search instruction from the operation switch 79, and the tape transfer is performed using the difference between the two time values. , It is possible to search for a desired tape position.

Usually, the tape transfer is controlled by a capstan servo. The reproduced signal from the amplifier 61 is L
The LPF 62 extracts only a pilot signal according to the four-frequency system, processes the pilot signal in a capstan servo circuit 63 including a well-known tracking control circuit, and drives the capstan motor 65 by a drive circuit 64.
Is driven to transport the tape-shaped recording medium 21.

In this configuration, a control signal is supplied from the system controller 74 to the servo circuit 63 so that capstan control according to an instruction from the operation switch 79 can be performed for the above search. FIG. 6 is a flowchart showing the operation of forming the control signal of the system controller 74.

Hereinafter, description will be made with reference to the flowchart of FIG. When an instruction of “date search” (or “time search” and “time counter search”) is given to the microcomputer 74 from the operation switch 79, the flow starts. The target value of the search instruction is read as information from the ten keys or the like of the operation switch 79 and is set in A. Subsequently, the current tape position is read from the tape, and the data decoder 7 reads the data.
5 is read into the microcomputer 74 and set to B. Then, in order to know the difference between the current position and the target position as time conversion, A-
Calculate B and set it to C. Here, it is determined whether the value of C is positive, negative, or zero (0). If C = 0, the process ends because the current value matches the target value. If C> 0, since the target value is first, the tape is transported in the forward direction. Furthermore,
If the value is larger than the predetermined value Th1, the fast-forward search (FF) is performed because the distance is some distance, and if the value is smaller than the predetermined value Th1, the normal reproduction (PALY) is performed because it is relatively close. C
If <0, since the target value is after, the tape is transported in the reverse direction. Further, if the value is larger than a predetermined value Th2 (= Th1 is also possible), an early rewind search (REW) is performed, and if the value is smaller than the predetermined value Th2, reverse reproduction (REV) is performed. Set these tape transfer modes as direction control mode,
The capstan servo circuit is controlled according to the direction control mode.

After the tape is transported in the above mode for a predetermined time, the current position is checked again, and the above operation is performed until the target value and the current value match.

In this manner, a "date search" for performing a tape search by designating a date becomes possible.

In the above-described apparatus, various additional information could be recorded without hindering high-density recording. Further, since this additional information is recorded as a low-frequency analog signal, it can be easily detected even when the tape is run at high speed. Furthermore, since a variety of additional information can be extracted during high-speed running of the tape, a completely new function called "date search" can be realized.

[0040]

As described above, according to the present invention,
The additional information signal indicating the date is recorded and reproduced together with the video signal, and the character signal generated based on the reproduced additional information signal is multiplexed arbitrarily with the reproduced video signal. Thus, character signals can be freely synthesized, and date information can be obtained even when no character signal is recorded.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a camcorder as one embodiment of the present invention.

2 is a diagram showing a spectrum arrangement of a recording signal by the camcorder of FIG. 1 and characteristics of a trap circuit in the camcorder of FIG. 1;

FIG. 3 is a diagram showing a recording format on a tape by the camcorder of FIG. 1;

FIG. 4 is a diagram showing a recording format of additional information data by the camcorder of FIG. 1;

FIG. 5 is a diagram showing a schematic configuration of a reproducing system corresponding to the camcorder of FIG. 1;

FIG. 6 is a flowchart for explaining the operation of the system microcomputer at the time of retrieval with the configuration of FIG. 5;

FIG. 7 is a diagram illustrating a schematic configuration example of a conventional camcorder.

FIG. 8 is a diagram showing an image obtained by the camcorder of FIG. 7;

[Explanation of symbols]

 Reference Signs List 3 camera signal processing circuit 4 time code generator 9 mode ID generator 11 f6 signal generator 12 modulator 18 adder 20-a rotating head 20-b rotating head 21 magnetic tape

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/91-5/956

Claims (1)

(57) [Claims] An imaging unit for generating a video signal; a date generation unit for generating date information; an additional information generation unit for generating an additional information signal indicating the date information; and the video signal and the additional information signal. Recording means for recording the video signal and the additional information signal from the recording medium; and a character video representing the date information based on the additional information signal reproduced by the reproducing means. A character signal processing unit that generates a signal and multiplexes the character video signal and the reproduced video signal; an operation unit that arbitrarily instructs whether to perform multiplexing of the character video signal on the reproduced video signal; The reproduced video signal and the character signal are multiplexed by the character signal processing means in response to an instruction from an operation unit. Recording apparatus and control means for controlling whether or not.