JPH0574124B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a device for adding image information to an audio signal in a rotating head type PCM recorder that records a PCM-converted audio signal on a magnetic tape using a rotating head. In particular, the present invention relates to a rotating head type PCM recorder suitable for recording and reproducing image information.

[Background of the invention]

Demand for higher quality audio equipment is increasing,
Advances have been made in the technology for recording and reproducing information on magnetic tape or rotating disk media using the PCM method, and products are now being supplied. Furthermore, due to the recent diversification of information technology, there is an increasing demand for recording and reproducing high-quality audio information and associated high-quality image information on the same medium.

However, conventionally, no product media or technology existed to meet this requirement. A closely related system is that the audio signal is converted to PCM even in VTRs.
I have an 8mm Video system that I'm trying to record with.

Figure 1 shows the tape format for 8mm video. 1-1 and 1-2 indicate the edges of the magnetic tape, and one track is 1-3.
It is configured as follows. In this one track 1-3, the audio RCM signal is in the area 1-4,
Image information is recorded in areas 1-5. In this case, image information is recorded by FM modulating an analog signal of one field per track. The angles in the figure are expressed as the cylinder winding angle of the magnetic tape.
The values shown are for NTSC format.

Here, the magnetic tape is wound around a rotating head at an angle of 221 degrees, and image information is recorded in an area 4 of 180 degrees. This image information is recorded using the low-pass conversion chromaticity signal recording method, which is the basic recording method for home VTRs. That is, the luminance signal is 4.2
FM modulated with ~5.4MHz carrier, color subcarrier is approx.
The signal is converted to a low frequency of about 740KHz, and both are frequency-multiplexed and recorded.

In addition, the PCM audio signal is subjected to predetermined noise reduction processing and recorded in 26.3° area 3 as a digital signal sampled at twice the frequency of the horizontal periodic signal and compressed from 10 bits to 8 bits. has been done.

However, since the image information occupies a 180° area, it is not possible to perform after-recording, in which the image information is played back and immediately recorded on the same magnetic tape, or the audio signal is played back and recorded immediately.

In addition, in a rotary head type PCM recorder that mainly records and plays back audio signals, the recording area for image information is naturally limited compared to the recording area for audio signals, so the image information is temporarily stored in memory. It is necessary to process from

[Purpose of the invention]

An object of the present invention is to address this problem and provide a rotary head type PCM recorder that is capable of after-recording.

[Summary of the invention]

Therefore, the present invention converts both image information and audio signals into PCM, divides the recording area, and separates both the image information recording area and the audio signal recording area for the rotating head.
The purpose is to record under conditions of 90 degrees or less.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In Figure 2, 2-1 is a magnetic tape, 2-2
represents a track, θ is a track angle, A is a tape width, W is an effective tape width, L is a track length, νt is a tape feeding speed, and νh is a relative speed.

FIG. 3 shows a magnetic head 3-2, approximately at the target position.
A wrap angle 3-7 is shown in which a magnetic tape 3-4 is wrapped around a rotating head cylinder (hereinafter referred to as a cylinder) 3-1 formed by a magnetic tape 3-3 arranged by guide posts 3-5 and 3-6. N represents the number of revolutions of the cylinder 3-1, and each head forms a recording track as shown in FIG.

FIG. 4 is a track area layout diagram expressed in cylinder angles when the diameter φ of the cylinder 3-1 in FIG. 3 is set to a predetermined value.

In FIG. 4, an area 4-4 of PCM-converted image information and an area 4-5 of PCM-converted audio signals are recorded separately.

First, it represents the total wrap angle, and p and s represent the angle of the image information and audio signal areas, respectively. Also, 4-1-1 and 4-2-
1 is a margin band at the start and end of signal writing, respectively. Furthermore, 4-3 is a signal unrecorded band (hereinafter referred to as a gap) formed by an angle a provided between the image information area 4-4 and the audio signal area 4-5.

Here, p and s are both set to be 90° or less.

For example, the total wrap angle is 120°, of which p is set to 32° and s is set to 69°.

Figure 5 shows an audio signal with image information added.
A basic configuration diagram of a PCM recorder is shown.

The input analog audio signal 5-1 is converted into a digital signal of a predetermined number of bits, for example 16 bits or 12 bits, by an analog-to-digital conversion circuit 5-9. This converted digital signal is encoded by an encoding circuit 5-10 in order to detect and correct data errors during transmission, recording, and reproduction. The encoded signal is recorded in the memory 5-11 and subjected to predetermined interleaving. The interleaved encoded data is encoded by an encoding circuit 5-12. Along with this, synchronization signals and control signals are added. This signal is transmitted to the modulation circuit 5
-13, predetermined modulation is performed.

On the other hand, the input analog image information 5-2 is converted into a digital signal of a predetermined number of bits, for example 8 bits, by an analog-to-digital conversion circuit 5-4. This converted digital signal is encoded with a predetermined code, such as Reed-Solomon encoding, in an encoding circuit 5-5 in order to detect and correct data errors during transmission, recording, and reproduction.

The encoded signal is recorded in the memory 5-6,
Apply predetermined interleaving. The interleaved data is encoded into a predetermined code, such as a CRC code, by an encoding circuit 5-7, and a synchronization signal and a control signal are added thereto.

This signal is subjected to predetermined modulation by a modulation circuit 5-8.

These signals are added alternately by an adder circuit 5-14. This added signal is amplified by the recording amplification circuit 5-18. The amplified signal is input to the signal switching circuit 5-20. This switching circuit 5-20 alternately supplies the output signal of the amplifier circuit 5-18 to the heads 5-2 and 5-3 in response to a control signal 5-19. As a result, an image information area 4-4 and an audio signal area 4-5 shown in FIG. 4 are formed on the magnetic tape for each head, and a gap 4-3 is formed between the two areas 4-4 and 4-5.
is formed. During reproduction, the output signals from heads 5-2 and 5-3 are controlled by control signal 5-19 so as to be supplied to preamplifier 5-22.

The output signal of this preamplifier 5-22 is input to demodulation circuits 5-23 and 5-31 and demodulated. This demodulated signal is transmitted to code identification circuits 5-24 and 5.
-32 and the code is identified. This code identified signal is transmitted to the error detection circuits 5-25, 5-33.
will be checked. This checked signal is
The data is input to data memories 5-26 and 5-34.

This memory performs predetermined deinterleaving, and decoding circuits 5-27 and 5-35 perform predetermined signals.

The output of this decoding circuit 5-27 is the memory 5-2.
8 is input. The output data of the memory 5-28 is subjected to a predetermined correction with respect to error data by an error correction circuit 5-29.

The output of this correction circuit 5-29 is converted into an analog signal 5-40 of image information by a digital-to-analog conversion circuit 5-30.

Next, the output of the decoding circuit 5-35 is subjected to a predetermined correction for error data by the error correction circuit 5-36, and then the output is sent to the digital-to-analog conversion circuit 5-3.
7, the audio analog output signal 5-41
is converted to

The above operations are controlled by control signals 5-17 and 5-39 from control circuits 5-16 and 5-38 including control pulse generation circuits.

Here, the control circuit 5.38 includes a synchronization signal detection/replenishment circuit.

FIG. 6 shows four magnetic heads 6-2, 6-3, 6-2 arranged at equal intervals of 90 degrees around the outer circumference of the cylinder 6-1.
4, 6-5 are attached, and the magnetic tape 6-6 is attached to tape guides 6-7, 6.
-8, the magnetic tape is wound around the cylinder 6-1, and the area recorded on the magnetic tape by one magnetic head is 90 degrees or less as in FIG. 4 above.

By using such a magnetic head, it is possible to perform after-recording, etc.

This will be explained with reference to FIG. 7 with after-recording. In FIG. 7, 7-1 is a playback system input terminal, 7-2 is a playback system circuit, 7-3 is a switch circuit, 7-4 is a control circuit, 7-5 is a recording system circuit,
-6 is a recording system output terminal. This FIG. 7 can be applied to either image information or audio signals. The control device 7-4 counts the distance of one track of the magnetic tape from the winding start end of the rotating head, turns on the trigger at the gap 4-3 position in FIG. 4, and turns on the trigger at the position of the margin band 4-2-1. A control signal to turn off the trigger is output, and while this control signal is ON and OFF, one magnetic head 6-2 is connected to the reproduction system circuit 7-2, and at this time, the recording system circuit 7 is connected to the magnetic head 6-2.
-5 is not connected. For the next track on the magnetic tape, switch 7-3-1, 7-3-
2 moves one step, and the magnetic head 6-3 is connected to the recording system circuit 7-5. Next, the magnetic head 6-4 is connected to the reproduction system circuit 7-2, and then the magnetic head 6-5 is connected to the recording system circuit 7-5. Therefore, while the magnetic head 6-2 is reproducing data, the next magnetic head 6-3 can be used for recording.

Conversely, in FIG. 7, by recording on the magnetic head 6-3 and then reproducing on the next magnetic head 6-4, it is also possible to check the recording state immediately after recording.

Next, the format of PCM-converted image information and the format of PCM-converted audio signal will be explained.

In FIG. 8, a indicates a block structure of image information, and b indicates a block structure of an audio signal. In figures a and b, 9-1 and 9-2 are synchronization signals, 9-3 and 9-4 are control signals, and 9-7 and 9-
8 is data, 9-5, 9-6 are signal data, 9-9, 9-10 are parity data, 9-1
1, 9-12 show other parity data.

Here, the block lengths of a and b, the synchronization signal patterns of 9-1 and 9-2, the number of control signal bits of 9-3 and 9-4, the number of data and the number of bits of 9-7 and 9-8, The parity data bit numbers and parity generation formulas of 9-11 and 9-12 are equally determined.

FIG. 9 shows a more specific embodiment of the block configuration according to the present invention.

One block consists of 160 bits, and the block consists of an 8-bit synchronization signal pattern, an 8-bit control signal, 8-bit data W _{1 to 12} , and P _{0 to 3.}
8-bit parity data and 16-bit CRC
In this example, W _{1 to 12} and P _{0 to 3} are interleaved data, encoded using a (16, 12) Reed-Solomon code of Galois field G·F (2 ⁸ ).

In the case of an audio signal, W1 _{to W12} indicate, for example, data obtained by dividing 16-bit quantized sampled data into two parts every 8 bits, and in the case of image information, the data is composed of, for example, 8 bits. The data for one dot is shown.

As described above, the audio signal and the image information are configured with the same code and the same format. By using the processing circuits in a time-division manner, the circuits can be shared and shared.

That is, demodulation, code identification, synchronization signal detection/protection, decoding circuits, etc. can be made common and shared.

FIG. 10 shows an embodiment in which a circuit is shared between an image information system and an audio signal system. In FIG. 10, the image information system and the audio signal system within the frames indicated by numerals 5-15 and 5-21 in FIG.
A modulation circuit 5-13, a demodulation circuit 5-31, a code identification circuit 5-32, an error detection circuit 5-33, and a decoding circuit 5-35 are omitted. In FIG. 10, the outputs of memories 5-6 and 5-11 are controlled and combined by a control signal 5-17 from a control circuit 5-16. The input/output of the memories 5-26 and 5-34 is controlled by the control signal 5-3 from the control circuit 5-38.
9 and separated.

〔Effect of the invention〕

As described above, the present invention divides the recording areas for image information and audio signals, and both the recording areas for image information and audio signals each have a lap of 90° or less under a predetermined cylinder diameter. Since it is a corner, it has the advantage of being able to perform after-recording in which recording is performed immediately while playing back, and that the recording status can be checked immediately while recording.

[Brief explanation of drawings]

Fig. 1 is a tape format diagram of 8mm video, Fig. 2 is a tape format diagram of an embodiment of the present invention, Fig. 3 is a diagram showing a rotating head and tape winding, and Fig. 4 is a tape diagram. 5 is a block diagram of the recording/reproducing system of FIG. 3, FIG. 6 is a diagram showing the four-head rotary head and winding of the magnetic tape, and FIG. 8 is a diagram showing the block configuration of image information and audio signals, FIG. 9 is a block configuration pattern diagram of a specific example of FIG. 10, and FIG. FIG. 3 is a block configuration diagram showing another embodiment of the recording/reproducing system according to the present invention. 3-1... Rotating head cylinder, 3-2, 3-
3... Magnetic head, 4-4... PCM converted image information area, 4-5... PCM converted audio signal area.

Claims (1)

[Scope of Claims] 1. Four magnetic heads are arranged at intervals of approximately 90 degrees on the outer periphery of a rotating head cylinder, and two magnetic heads of the four magnetic heads are arranged facing each other at intervals of approximately 180 degrees. The head is used as a recording magnetic head, and the remaining two magnetic heads are used as reproduction magnetic heads, and a first area on the magnetic tape is used to record PCM-converted audio signals and a PCM-converted image information is recorded. The second region is divided, and each of the first region and the second region is converted into PCM separately with the wrap angle being 90 degrees or less with respect to the rotating head cylinder of a predetermined diameter. 1. A rotary head type PCM recorder that records audio signals and image information on the magnetic tape. 2. Rotating head type according to claim 1
In the PCM recorder, the two reproduction magnetic heads reproduce the PCM-converted audio signal or image information, and the remaining two recording magnetic heads record the PCM-converted audio signal or image information. A rotating head type PCM recorder characterized by: 3. Rotating head type according to claim 1
In the PCM recorder, the recording format of the audio signal and the recording format of the image information are characterized in that at least one of a synchronizing signal pattern, a block format, and an error detection/correction code is the same. Head type PCM recorder.