JPS6174179A - Video disk recorder - Google Patents

Abstract

PURPOSE:To eliminate the interference of jitter correction by multiplexing a PCM sound signal at the amplitude of >=60% for the amplitude of a band compressed signal and FM-converting the result and recording in a multiplexing way a pilot signal to the low band side of an FM modulating signal, in a blanking period of a band compressed video signal. CONSTITUTION:A high grade video signal is converted to a MUSE signal by a MUSE encoder, further, a two-channel sound signal is data-compressed by a PCM encoder 2 and stored in a memory 3. PCM sound data are time- compressed and supplied at a time division multiplex circuit 6 for a vertical blanking period of an MUSE signal. The amplitude of the PCM sound signal is >=60% for the amplitude of the MUSE signal. A time division signal made multiplex at the circuit 6 is modulated in an FM modulating circuit 7, further, in the modulating signal, a pilot signal is made multiplex at the low area side of the modulating signal by a frequency multiplex circuit 8 and is a record signal. Thus, the level of an FMPCM signal at the time of reproduction can be made small to the extent that interference will not be introduced to a reproducing pilot signal, and the interference for jitter correction can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION A] Field of Industrial Application The present invention relates to an improvement in a video disc recorder for recording high-quality video signals.

(Example 1) Conventional technology A high-quality video signal is band-compressed using the TLR multiple sub-sampling method, and digital signals such as PcM audio signals, control signals, and block control signals are multiplexed during the blanking period of this band-compressed video signal. Furthermore, regarding the method of converting into a broadcast signal and transmitting it, please refer to pages 103 to 108 of the April issue of the magazine "Radio Science" published by the Japan Broadcast Publishing Association on April 1, 1981, and the TV Proceedings of John Society Technical Report (published March 22, 1980) THB
It is explained in detail as the electric σsg method in S95-2 and the like. l (Hereinafter, the signal formed by this method will be referred to as M
It is called the USF signal. ) MO3F obtained by the method described above! Regarding the method of recording signals on video disc records, the applicant previously proposed the MUSE signal f' in Japanese Patent Application No. 59-47764.
In addition, the applicant proposed a method of multiplexing and recording pilot signals for shifter correction using M modulation.
No. 54899, after multiplexing a PCM audio signal during the vertical blanking period of the MUSB signal, the entire signal is F'
We proposed a method for M modulation recording.

The fifth factor is the signal arrangement diagram for one frame of the MUSE signal multiplexed with the PCMf voice signal during the vertical blanking period.As is clear from this diagram, one frame is 1125
One line corresponds to 480 sample clocks, and the clock frequency is 16.2 MHz. Each line initially transmits a horizontal synchronization signal for 12 clocks, and other information is transmitted for the remaining 468 clocks.

First, the color information C01)C02) in the video information is transmitted for 94 clocks following the horizontal synchronization signal, and the transmission line is the 44th to 562nd lines for a total of 519 lines in the odd field, and the 607th line in the even field. ~11
25 lines, a total of 519 lines ≠ Kui ≠.

In addition, luminance information (Yl) (Y2J) in the video information is color information [Subsequently, the transmission line is transmitted to 375 Kurofuku, and the transmission line is the 48th to 1!566th line for a total of 519 lines in the even field, and furthermore for the even field. 10,000 611~
The 1129th (jJ4) line is a total of 519 lines, and the control signal (CNIJ (CN2)) required for conversion to the MUSH signal is based on color information (CIJ (CN2)).
C2) is multiplexed into an area of four lines following C2). This control signal is encoded into 64-bit data, with 4 clocks per baud for each line.
By transmitting data of 0biz, each field carries a control signal f, 3. Therefore, the maximum frequency of the control signal is 4. Q5MHz.

Furthermore, a block control signal (BCl) (BO2) required for conversion to a MUSI signal is multiplexed in an area for four lines following the luminance information (Yl) (Y2). This block control signal is 528
It has 528 bits of data corresponding to the block, which is converted to 650 bits of data by encoding, and 2
180 bits of data are multiplexed for each line, with one baud being counted as one baud. Therefore, the maximum frequency of the block control signal is also 4. Q5MHz.

The frame synchronization pulse is transmitted to the 605th line and the 606th line, forming an area in the upper half of each line where the level is inverted to high and low binary values at four clock cycles.

Furthermore, during the vertical blanking period, the PCM1 voice signal (AI
J (A2J is multiplexed. This PCM audio signal is
1 audio signal for 2 channels at a frequency equivalent to 32KHz
After 4biZICAD conversion, compressed to 10bit and 640
1. By converting the Kbit, /sea data into the A-mode signal of the wave sound council.
024Kbit/sea data, 45Kbit/sea of each line.
456-bit data is sequentially multiplexed into 6 blocks. Therefore, the maximum frequency of the p c uf voice multiple signal is 8. I
MHzK-71-ru. Note that this PCM audio signal is displaced by the maximum width in consideration of readability during reproduction.

The MUSE signal configured as described above will be FM modulated during recording, and the partial transplantation of this F'M modulation will produce a minimum level of t 12 MHZ and a maximum level of 16 MHZ, as shown in the sixth prisoner.
It is set as z. Further, a pilot signal for shifter correction is multiplexed onto this FM modulated signal and recorded on a video disc record.

Regarding this pilot signal frequency, in the earlier application, 75
9.395KHz, but as a result of subsequent consideration,
In view of the request to correct higher frequency jitter and to be able to multiplex other digital signals (for example, Taka 2's PCM audio signal) into the low frequency range, we changed the clock frequency to 16.2M1 (z to 9764). 2,278 obtained by multiplying
MHz (-67,5fH)? The pilot signal frequency is set at a level of -20 dB relative to the video signal.

P”4 Problem to be Solved by the Invention When playing back a video disc record recorded as described above, the maximum @ wave number of the PCM audio signal multiplexed during the vertical blanking period is 8.1 MHz, and the IF M In the modulated part, the first lower side wave (31) becomes !1-9 MFIZ, which is 8.1 MHz lower than the center 14 MHz of the FM shift band.Furthermore, the second lower side wave (S2) folds the band. 2, 21fiz
becomes. This second lower side wave (S2) is a biloft signal (
It was confirmed that PJ and 22KH2L were not far apart and would interfere with shifter correction.

Therefore, the present invention provides a means for solving the problem by controlling the level of the PCM audio signal.
The maximum amplitude of the signal is limited to 6096 or less, and the MU
It is characterized by being multiplexed onto the Sg signal.

(e) Effect: Therefore, according to the present invention, since the level of the PCM audio signal before FM modulation is small, the level of the second lower side wave of the FMPCM signal during reproduction may cause interference to the reproduced biloft signal. It becomes small to the degree that it does not give. Example of Breeding The present invention will now be described in accordance with an illustrative example.

First, in this embodiment, a high-quality video signal is converted into a MUSEi signal by a MUSE encoder. Furthermore, the PCM encoder +21 outputs a 2-channel audio signal f 32 K.
While sampling with a Hz sampling clock, 1
After performing 4-bit AD conversion, the data is compressed to 1Qbit and converted to an A-mode signal. Configuration 1 per I IIIgso of this person mode signal! : Shown in Figure 2. In deriving 640 btt audio data for 1m5ea, this human mode signal precedes a 16-bit frame pattern, 16-bit control bit, and 32-bit range bit, and also includes 96-bit "0 // data, 224-bit, followed by the BCH code of 10
It is 24-bit PCM audio data. This PC
The MV voice data is sequentially input to the memory +31, and the MUS1
A time division multiplexing circuit (61
This supplied PCMf is compressed on the time axis and supplied to
The f voice signal iAl is an NRZ signal that is made by reading PCM voice data in synchronization with the 16-2MHI+ sampling clock.
symbol, and its level is the DC level MUSI! as shown in FIG. 3 IAI! It is set at the center of the domain of the signal, and its amplitude is set to half the top of the domain of the MUSg signal.

Furthermore, regarding the amplitude of this PCMt voice signal, MUSI! It has become clear from the results of reproduction characteristic measurements that it is desirable to define the signal in the range of 3096 to 6096.
It has been confirmed that there is almost no problem with changing the DC level of the pcMfyR signal, but it goes without saying that it is better to set it at the center of the MUSE signal as long as the frequency characteristics during playback are considered. Nor.

Furthermore, in this embodiment, considering that the first half of the two frame synchronization lines are in a blank state, address data and codes are time-division multiplexed in this blank area. This address data is time-division multiplexed onto both lines of odd-numbered frames and the previous line of even-numbered frames, and the code is time-division multiplexed onto the following line of odd-numbered frames. Furthermore;-do is
It is assumed that chapter codes and time codes are alternately multiplexed. Also, address data and code are both 2
A 3-bit data pin H'C is preceded by a 14-bit synchronization pin I-, making up a total of 34 bits. This 54b
The data of it is bi-phase encoded as shown in Figure 3 (AD) and multiplexed so that 1 bit of data is sucked in with 8 clocks, and the maximum frequency is 2.05 MHz.
becomes. Address data generation circuit (4) as described above.
The address data and the code of the code generation circuit (5) are multiplexed in a time division multiplexing circuit (6). Note that the amplitude of the address data and code is equal to the domain of the MUSK signal.

This time-division multiplexed signal is modulated in an FM modulation circuit (71).The modulation shift range is 12 MH7 for the black level and 16 MHz for the white level, and the first lower sideband extends to 4 MHt.

Furthermore, this modulation signal (7) is passed through a frequency multiplexing circuit (81) to generate a biloft signal (E'), which is multiplexed and becomes a recording signal.
It is formed by inputting the output of 9; to the pilot signal generating circuit q (J) and inputting it to the 9/256 column.

The oscillation frequency of this oscillation circuit 'a5111m is the same frequency as the oscillation circuit that should be built into a high-quality video camera, and it is also possible to share these oscillation circuits.
``!This pilot signal has a Bohira synchronous signal station wave number f
By selecting 67.5 times H, the frequency is interleaved with the MUSE signal, and in order to prevent harmonics from having a negative effect on the FM lower sideband, the level is 120 dB lower than the total FM modulation signal. There is.

The recording signal multiplexed in column wave number in this way is recorded as a spiral track on a video disc record that rotates at a field period. The disc player has a circuit configuration as shown in FIG.

The reproduced signal optically reproduced from the big afugu is amplified by an amplifier fi3, and then input to a bypass filter I with a passband of 4MH2 or more and a bandpass filter (151) with a selected frequency of 6'1.5tH. .

The bypass filter output is input to the next stage FM demodulation circuit σ61 and converted into the original time division multiplexed signal. This time division multiplexed signal is input to the PCM audio signal amplification circuit +281. This PCI audio amplification circuit (■) limits its tRIFi to stations during the vertical blanking period, and multiplexed P
This is a circuit that shapes the waveform of a CM audio signal using a comparator that is installed at home, and then amplifies it to the same amplitude as the MUSI signal. Therefore, the subsequent signal switching circuit selects this amplified output only during the vertical blanking period and F' during the remaining period.
The M demodulation output will be selected. This switching output will be input to the +1 U S g decoder attached to the high-definition television receiver. This MO3MO3-der will select the MUS
It performs the opposite operation to the Ei encoder and also functions to convert the PCM audio signal to the original analog f-true signal.

On the other hand, the address latch circuit that inputs the FM demodulation output latches the address code multiplexed on the vertical synchronization line and supplies the access circuit (not shown) with the K address code to realize access to the desired address of the big bug. On the other hand, the reproduced pilot signal and the aforementioned second lower side e are derived from the bandpass filter (151), but as a result of the level of the PCM audio signal being suppressed to H during recording, the second lower side wave is reproduced. The level is sufficiently low compared to the pilot signal, and it has no substantial effect on the jitter correction circuit below, so it can be assumed that only the reproduced pilot signal is input to the phase shift circuit σ. .

This phase shift time v! ! At t1η, the reproduced biloft signal is phase-shifted by 90°, and this phase-shifted output is used as the comparison input of the first comparison circuit.

The output of a fixed oscillator (19) is input as the reference input of this first comparison circuit a81.
An'71 I emits a single signal. The first phase comparison circuit described above is composed of a multiplication circuit and a low-pass filter, and derives the low frequency component in the multiplication output as a phase comparison output. This phase comparison output is input to the drive coil lη of the tracking mirror CT via the phase correction circuit 12G. Therefore, since the reproduction beam changes the reading position in the track direction in accordance with the shifter, a reproduction information signal with almost no residual shifter is derived.

In this practical example, jitter is removed by mechanical correction means, but if the response of the tracking mirror is slow and high frequency shifter cannot be removed, a variable delay circuit (electrical correction means) such as COD may be used. After the amplifier α3 or F
The M demodulation circuit (161) may be provided at the subsequent stage to mainly remove the high frequency shifter.

Furthermore, as a method for simplifying electrical correction, two stages of sample and hold circuits are successively connected to the signal line, and the sample and hold circuit in the first stage is operated with a constant clock, and the sample and hold circuit in the second stage is operated at a constant clock. Even if the phase) is controlled according to the shifter, a small residual jeuta correction is possible.

In this embodiment, a reproduction pilot signal is also input to the disc servo circuit (21+) to control the rotation of the disc motor (2) on the video disc player side.

7) The regenerative pyro signal is input to the AP'C circuit to compensate for dropouts, and then is input to the first minute circuit C.
I! 41. On the other hand, the reference signal is input to the second branch circuit 4. The above-mentioned double splitting circuit (24 divides the splitting value by 1/
135, and the rotation detection signal and reference signal are in the category 2.
The signal is input to the phase comparison circuit wr■.

This phase ratio \i small output is supplied as the rotation II control signal of the disk motor (Company) via the second phase compensation circuit (271).

Incidentally, it is better to set the phase comparison period of the second phase comparison circuit to a certain length so as to include the rotation variation range of the video disk record, and at least the phase comparison period of the first phase comparison circuit ag
It is impossible to make all the phase comparison cycles common, and the branch output of the branch circuit must be set to 20 KHz or less.

()l According to the present invention, since the PCM audio signal level is suppressed and FMf tone is created according to the present invention, the level of the second lower side wave generated in the vicinity of the reproduced by-low J) signal becomes sufficiently small during playback. This does not interfere with jitter correction, and the effect is great.

[Brief explanation of the drawing]

FIG. 1 is the main circuit block causes of a video disc recorder according to an embodiment of the present invention, the second figure is an explanatory diagram of the data arrangement of the A mode signal, and the third figure is the PCMt voice signal and address of the present example; - Figure 4 is a block diagram of the main circuit of the video disc player of this embodiment, Figure 5 is a diagram explaining the signal arrangement of the time division multiplexed signal, and the sixth factor is an explanation of the frequency characteristics of the recording signal. Figures are shown respectively. +ll・MUSE decoder, +21-...PC
M decoder, +31...Memory, (61...Time division multiplex circuit, (7)...FM modulation circuit Higanin Sanyo Electric Co., Ltd.

Claims (1)

[Claims] (1) A high-quality video signal is band-compressed using the TCI multiplex sub-sampling method, and during the blanking period of this band-compressed video signal, a PCM audio signal is multiplexed and the whole is FM-modulated, and the FM-modulated signal is A video disc recorder that optically records a recording signal multiplexed with a constant frequency pilot signal on the band side, characterized in that the amplitude of the PCM audio signal is 60% or less of the amplitude of the band compression signal. video disc recorder.