JPH0240165A - Rotary head type recorder - Google Patents

Abstract

PURPOSE:To enable information to be extracted even when a tape shape recording medium is carried at high speed by performing the frequency multiplexing of a carrier signal with a frequency less than the dedicated frequency of a main information signal on the main information signal after modulating by an additional information code, and recording plural kinds of additional information codes on one track. CONSTITUTION:The plural kinds of additional information codes are recorded on one track with the main information signal by frequency-multiplexing 18 a carrier additional information signal obtained by modulating 12 the carrier signal with the frequency less than the dedicated frequency of the main information signal on the main information signal. Thereby, it is possible to record multiplexed and plural kinds of information as the additional information codes without providing a specific recording area, and also, since the additional information is recorded as an analog signal with a low frequency, it is possible to render the additional information code even in a state where a tape 21 is carried at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary head type recording device, and more particularly to a rotary head type recording device for recording an additional information code on a tape-shaped recording medium together with a main information signal.

[Conventional technology]

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

FIG. 8 is a diagram showing an example of the configuration of a conventional camcorder. Conventionally, the time information recording/reproducing device in a camcorder is
As shown in the figure, the output signal of the character information generator 5 based on the time code from the time code generator 6 is transmitted to the optical system 1. Image sensor 2. An adder 4 adds a video signal output from a well-known circuit such as a camera signal processing circuit 3 to an adder 4.
It is multiplexed in .

That is, the time code was recorded as character information in the form of a video signal. The video signal on which this character information is multiplexed is an audio signal (Andio) and four types of pyroft signals (4f) used for tracking control using a four-frequency system.
At the same time, the recorder signal processing circuit 7 converts the signal into a recording signal in a signal format suitable for recording, and the amplifier 8. After passing through a head switch 11, the data is recorded onto a magnetic tape 10, which is a tape-shaped recording medium, by rotary heads 9-a and 9-b.

When the above-mentioned signal is reproduced, the information recorded by the time code generator 6 is projected on a part of the video imaged by the optical system, as shown in FIG.

Other recording methods for time codes include recording on longitudinal tracks formed at the ends of the tape, and providing a subcode recording area in each track separate from the main information recording area. There are methods such as recording it as a code.

[Problem that the invention seeks to solve]

First, when recording the time code as character information as a video signal, since it is superimposed on the video signal, it always overlaps with the image capture screen during playback, and it is impossible to separate the date from the image capture screen during playback. Can not. Furthermore, the photographer is required to set the date for playback and to turn on or off the operation switch depending on whether it is necessary or not, at the time of recording. Furthermore, due to this, it has been impossible to know the time information on the screen where character information indicating the time code is not imposed.

In addition, when recording time codes on longitudinal tracks, the relative speed between the fixed head and the tape is low, and it is not possible to record multiple information, so it is necessary to record codes with small time units as time codes, and to record various additional information. It was difficult to record. Furthermore, it is necessary to provide a fixed head, which is undesirable in that it causes wear of the tape and complicates the mechanical part.

Furthermore, when the time code is recorded as a subcode in the subcode area provided on each track, it is difficult to read this subcode information when the tape is running at high speed, for example, when performing a forward/reverse search on a VTR. This tendency is even more remarkable when azimuth recording is performed. Further, providing a subcode area in each track hinders high-density recording.

In view of the above-mentioned background, the present invention has been developed so that it can be extracted even when a tape-shaped recording medium is conveyed at high speed.
Another object of the present invention is to provide a rotary head type recording device that can record a large amount of additional information codes without hindering high-density recording.

[Failure to solve the problem]

For this purpose, the present invention provides an apparatus for recording a main information signal with a rotary head while forming a large number of parallel tracks on a tape-shaped recording medium. A configuration in which a plurality of types of additional information codes are recorded on one track together with the main information signal by frequency multiplexing a carrier additional information signal obtained by modulating a carrier signal having a frequency with an additional information code with the main information signal. It is said that

[For production]

By configuring as described above, multiple types of information can be recorded as additional information codes without providing a special recording area. Furthermore, since the additional information is recorded as a low-frequency analog signal, this additional information code can be reproduced even when the tape is transported at high speed.

〔Example〕

Examples of the present invention will be described below.

FIG. 1 is a diagram showing a schematic configuration of a camcorder as an embodiment of the present invention, in which light rays from a subject (not shown) enter through an optical system 1 and form an image on an image sensor 2. As shown in FIG. 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 (2:01 on February 9, 2016) in the form of a digital signal from a circuit using a so-called digital clock similar to the conventional example.

seconds) are generated. This data is a time code related to the time at the time of image capture or a time counter from the beginning of the tape in use.

As in the conventional example, the time code is converted into a television signal format as required by the character generator 5, and multiplexed onto the captured television signal. The imaged television signal outputted from the camera signal processing circuit 3 and the character generator 5
The character signal related to the output time code is sent to the adder 6.
The images are combined.

The television signal synthesized by the adder 6 is converted into a well-known recording signal according to a predetermined recording format of the VTR. That is, the audio signal collected by the microphone 16 is FM modulated by the audio processing circuit 15, and this FM modulated signal is sent to the adder 14 together with the 4-frequency tracking pilot signal output from the 4-frequency generator 13. and is combined with the video signal output from the recorder signal processing circuit 7.

The output of the above-mentioned time code generator 4 is connected to the operation switch 26.
The data is supplied to the data encoder 8 together with the code output from the various mode identification ID signal generator 9 according to the operation. Using the output of the data encoder 8, a gate circuit 12 switches (amplitude modulates) a signal of frequency f6 generated by the pilot signal 11 (hereinafter referred to as f6 signal). The output of the gate circuit 12 is superimposed in an adder 18 with the trapped f6 component of the signal according to the predetermined recording format.

The frequency of the pilot signal is selected in such a way that interference with the frequencies of the various signals conventionally used in VTRs is minimized. The conventionally used frequencies include four types of pilot signals (100K to 200K) for tracking using a four-frequency method.

Pilot signal of frequency f5 (200 to 300K) used for DTP control or multi-channel recording discrimination of PCM audio and chroma low frequency conversion signal (
743 ±350K). Even if it supports sMPTE time code, the time code in the VTR of this embodiment can be recorded if there is a band of approximately 10 KHz. Therefore, a frequency with a margin of more than IOK from the upper limit of the f5 signal (approximately 300K) and the lower limit of the chroma low-frequency conversion signal (approximately 400K) is set as f6 and is used as a modulation carrier.

The trap circuit 17 described above is for removing the frequency component corresponding to f6 from the original recording signal in order to prevent malfunction. FIG. 2 shows a frequency spectrum arrangement diagram after the f6 multiplexing described above, and FIG. 3 shows a frequency characteristic diagram of the trap circuit.

The recording signal generated in this way is amplified by a recording amplifier 19, passed through a switch 24 that is switched by a 30PG pulse with a frame period, which will be described later, and is recorded on a tape by two rotating heads 20-a and 20-b having different azimuth angles. It is recorded while forming a recording track.

The rotation of the rotary drum to which the rotary heads 20-a and 20-b are attached is controlled by a rotary phase detection head 22. It is detected by the amplifier 23, and the above 30PG is detected by the timing circuit 25.
Delay processing and the like are performed so that the pulses are output at a predetermined timing. This 30PG pulse is used by the data encoder circuit 8 as a reference timing for generating sync data for the time information array for each track.

The recording track pattern of the VTR of this embodiment is shown in FIG. 4. Recording signals including a video signal, an FM modulated audio signal, and a modulation signal of an f6 signal are recorded alternately in the video recording track area in positive azimuth and negative azimuth. As a modulation signal for the f6 signal, information indicating the photographing time is recorded on the plus azimuth track, and time counter information from the end of the tape in use is recorded on the minus azimuth track. The part indicated by ID in the figure is mode data indicating the content of the time code of each track.
1 J.

"IO" corresponds to the shooting time and the time information from the end of the tape, respectively.This ID word is placed in the center of each track to be advantageous when searching as will be described later. When the tape is run at high speed, the reproduction envelope cannot be obtained over the entire track, so the mode information is arranged at a position close to the information effective for actual search to increase the probability that reproduction can be detected at the same time.

The ID word can also be used as a check bit to prevent malfunctions on tapes recorded with devices that do not employ this system. For this purpose, bits should be allocated avoiding "11" and "00".

For example, starting from the bottom of the tape, the information indicating the time of shooting is February 9, 2007, and the mode information is 9 o'clock.

Each minute and second of information is recorded. In actual digital data recording, in addition to the above contents, clock run-in (32 bits) and sync data (16 bits) are recorded as shown in Figure 5.
bit) at the beginning of the information, and a CRC (8 bits) for error correction is provided at the end of the information. Also, the 1st of the month.

Hours 2 minutes 2 seconds, maximum code indicating frame and ID is 7b
A 1-bit parity check bit is provided as it, and it is handled as a total of 8 bits. That is, during a search, only error detection can be performed using the 1-bit parity, and during normal playback, error correction can be performed on a track-by-track basis.

Incidentally, Table 1 shows an example of mode setting using 2 bits out of 7 bits of ID data.

Next, data detection and search operations during playback will be explained.

FIG. 6 shows an example of the configuration of a reproduction system corresponding to the camcorder shown in FIG. 1. From the tape 21, the rotary head 20-a.

The signal detected at 20-b is the head drum 180
It is switched by a switch 60 at 30PG every degree rotation, amplified by a 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 sent to the timing circuit 51.
The signal is then supplied to the switch 60 and the data decoder 75 as a 30PG pulse at a predetermined timing. The data decoder 75 uses the 30 PG pulses to determine the azimuth angle.

BPF66 is a band pass filter for extracting audio signals, BPF67 is a band pass filter for extracting chroma signals, and HPF68 is a bypass filter for extracting luminance signals. The signals extracted from each of these filters are used for recorder playback signal processing. The circuit 70 performs processing that is the reverse of that during recording.

BPF69 is a band pass filter for extracting the f6 signal, and its center frequency, band, etc. are matched to the f6 signal carrier frequency and sideband waves. The output of this BPF 69 is detected by a detection circuit 71. The waveform shaping circuit 72 converts it into a digital signal. Furthermore, this digital signal is demodulated into a time code by a data decoder 75. During demodulation,
The aforementioned 30PG pulse is used as auxiliary information to detect the start point of clock run-in and to determine the azimuth angle for mode determination when ID data cannot be detected.

In this manner, the demodulated time code is supplied to the character generator 76 to obtain character information. Adder 7
7) After this character information is multiplexed on the luminance signal,
is supplied by an NTSC encoder 78, and the encoder 7
8, it is made into a composite video signal and output together with the demodulated audio signal.

The device of this embodiment is thicker than the conventional device (the difference is that a signal from an operation switch 79 is supplied to a character generator 76 via a system control microcomputer (hereinafter referred to as system controller) 74). As a result, by operating the operation switch 79 during playback, you can arbitrarily multiplex the time code to the video information.
All the output data of the decoder 75 is transferred to the character generator 7.
6 should be replaced with data corresponding to the blank.

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

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

This configuration further includes the system controller 7 so that the capstan can be controlled in accordance with instructions from the operation switch 79 for the above-mentioned search.
4 supplies a control signal to the servo circuit 63. The control signal forming operation of the system controller 74 is shown in a flowchart in FIG.

The process will be explained below according to the flowchart shown in FIG.

When an instruction for "date search" (or "time search" or "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 numeric keypad of the operation switch 79 and set in A. Subsequently, the current tape position is read from the tape, and read from the data decoder 75 to the microcomputer 74 and set to B. Then, in order to know the difference between the current position and the target position in terms of time, calculate A-B and set it to C. Here, the value of C is positive, negative, zero (0
) to judge. If C=0, the current value and target value match, and the process ends. If C>0, the target value is located first, so the tape is transferred in the forward direction. Furthermore, if the dog is less than the predetermined value Thl, the dog is a certain distance away, so a fast forward search (FF) is performed, and if it is less than the predetermined value Thl, the dog is relatively close, so normal playback (PALY) is performed. If C<0, the target value is behind, so the tape is transferred in the opposite direction. Furthermore, if it is larger than the predetermined value Th2 (-Thl is also possible), the early spring return search (REW) is performed, and the predetermined value Th
If it is smaller than 2, reverse playback (REV) is performed. These tape transport modes are set as direction control modes, and the capstan servo circuit is controlled according to the direction control modes.

After the tape is transferred in the above mode for a predetermined period of time, the current position is checked again, and the above operations are performed until the target value and the current value match.

In this way, it becomes possible to perform a "date search" in which a tape is searched by specifying a date.

In the apparatus of the above embodiment, various additional information could be recorded without interfering with high-density recording. Furthermore, since this additional information is recorded as a low-frequency analog signal, it can be easily detected even when the tape is running at high speed. Furthermore, since a variety of additional information can be extracted while the tape is running at high speed, a completely new function called ``date search'' has become possible.

〔Effect of the invention〕

As explained above, according to the rotary head type recording device of the present invention, it is possible to extract even when a tape-shaped recording medium is conveyed at high speed, and a large amount of additional information code can be extracted even when the tape-shaped recording medium is conveyed at high speed. It can be recorded together with the main information signal without any interference.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a camcorder as an embodiment of the present invention, FIG. 2 is a diagram showing a spectrum arrangement of a recording signal by the camcorder of FIG. 1, and FIG. Figure 4 is a diagram showing the recording format on the tape by the camcorder of Figure 1; Figure 5 is a diagram showing the recording format of additional information data by the camcorder of Figure 1; The figure shows a schematic configuration of a playback system corresponding to the camcorder shown in Figure 1. Figure 7 is a flowchart for explaining the operation of the system microcomputer during a search using the configuration shown in Figure 6. Diagram 9 showing a schematic configuration example of a camcorder
The figure shows an image obtained by the camcorder of FIG. 8. 3 is a camera signal processing circuit, 4 is a time code generator, 8
is a data encoder, 9 is a mode ID generator, 11 is f
6 signal generators, 12 modulators, 18 adders, 20-a
, 20-b is a rotary head, and 21 is a magnetic tape.

Claims (2)

[Claims] (1) A device that records a main information signal using a rotating head while forming a large number of tracks parallel to each other on a tape-shaped recording medium, wherein the carrier signal having a frequency lower than the exclusive band of the main information signal is used as additional information. By frequency multiplexing the carrier additional information signal obtained by modulating the code with the main information signal,
A rotary head type recording device characterized in that a plurality of types of additional information codes are recorded on one track together with the main information signal. (2) The rotary head according to claim (1), wherein the plurality of types of additional information codes are recorded one by one in a plurality of segments obtained by dividing the recording area of the main information signal in the one track. Type recording device.