JPS6016794B2 - Information signal recording and reproducing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information signal recording and reproducing system in which a reproducing scanner accurately scans a spiral or concentric track formed on a flat rotating recording medium without a needle guide groove. It is an object of the present invention to provide an information signal recording and reproducing method capable of stably reproducing information for tracking control without adversely affecting recording and reproducing of main information signals (particularly video signals).

Previously, in Samurai Nukasho 51 Ishishi No. 809, the present applicant recorded a reference signal for tracking in the intermediate portion between each main information track, and reproduced this to reproduce the reference signal (for example, a capacitor). Tracking control of a scanning needle that detects changes, a scanning needle that has a transducer that converts mechanical vibrations into electrical signals, or a device that includes a light emitting element and an element that measures changes in the light intensity of reflected (or transmitted) light beams) We have proposed an information signal recording and reproducing method that eliminates the need for a needle guide groove by using this method.

However, in this proposed method, the signal Np2, which has different frequencies, is switched and recorded every rotation period of the rotary recording medium as a reference signal in the dark middle part of each track of the main information signal recording track. According to the main information signal. In the invention in which the recording tracks of nap, p, and p2 are arranged alternately on both sides of the rack, during playback, the error voltage of the tracking servo 0 is detected at the same position where p,, and p2 are switched during recording. It is clear that the tracking operation cannot be continued unless it is alternately reversed every rotation period.

Therefore, in order to reverse the error voltage mentioned above, a hole, for example, for a pin to be inserted, for detecting the above-mentioned switching position, which is one place per rotation period of the rotating recording medium, is made on the mechanically pressed board. However, it is preferable to use a means for detecting the switching position in a proactive manner depending on the playback device and the like.

The present invention satisfies the above-mentioned requirements and is capable of satisfactorily detecting a switching error without adversely affecting a video signal, and will be described below with reference to the drawings and embodiments thereof.

FIG. 1 is a block system diagram of the first embodiment of the recording system of the information signal recording/reproducing method according to the present invention, and FIG.
A signal waveform diagram for explaining the operation of the figure is shown.

In FIG. 1, a video signal a shown in units of fields in FIG.
The synchronizing signal is separated here and supplied to a mixer 14, which will be described later. Here, for convenience of explanation, we will explain the case where four fields of video signals are recorded and reproduced per one rotation period of a rotating recording medium such as a disk (therefore, the field frequency of video signal a is 60
Hz, the rotation speed of the rotating recording medium is 90 pm). The output signal of the synchronization signal separation circuit 2 is supplied to a vertical synchronization signal separation circuit 3, a JK flip-flop 8, and a gate circuit 9, which will be described later.

The vertical synchronizing signal b as shown in FIG.
After being counted down by 2, the flip-flop 5 further counts down by 1'2. flip flop 4,
Each output pulse of 5 is as shown by c and d in Fig. 2C and D,
The repetition frequency is 1'2,1/of the field frequency.
4 and both are supplied to the gate circuit 9. On the other hand, the vertical synchronization signal is transmitted by cascaded monostable multipipulators 6 and 7.
The pulse is made to have an appropriate position and width, and then J-K
The pulse e is synchronized with the synchronizing signal by the flip-flop 8 and is supplied to the gate circuit 9 after being made into a pulse e shown in FIG. 2E.

As a result, as shown in FIG. 2F, from the gate circuit 9, 4
A pulse signal having a field period and a pulse width of 1 to several H (days are horizontal scanning periods) within the vertical blanking period of the video signal a is output from the gate. FIG. 2G shows the vertical synchronizing signal and equalization pulse during the vertical line erasing period of the video signal a, and shows an enlarged waveform near the pulse width n of the output pulse n of the gate circuit 9.

The output pulse of the gate circuit 9 is the pulsed oscillator 1.
0, inverting amplifier 11 and monostable multipipulator 12
are applied respectively. As is well known, a pulsed oscillator is a circuit that oscillates and outputs a sine wave only when the input pulse is logic "1" or "0", and in this example, the logic "0" is used.
The structure is such that it oscillates only when . Therefore, the output signal of the pulsed oscillator 10 is shown in FIG.
1), and V is supplied to the mixer 140.
Note that the output oscillation frequency of the pulsed oscillator 10 may be arbitrary, but it needs to be sufficiently higher than the synchronization signal frequency. Actually, good results can be obtained at about IMHZ to 2MHZ. The pulse signal inverted and amplified by the inverting amplifier 11 is supplied to the mixer 14, where it is mixed with the signal i and the video signal a at a predetermined level ratio.

As a result, as shown in FIG.
A video signal i, in which a sine wave is superimposed at a gray level on an equalized pulse (here, an equalized pulse), is sent from the output terminal 14 to a frequency modulator (not shown), for example, to a recording light beam modulator (not shown) as a modulation signal. Output. A frequency-modulated video signal i is recorded by the output modulated light beam of this modulation device, forming a spiral or circular main track on the rotating recording medium. It is clear from the above explanation that the sine wave and gray level superimposed portion in the video signal i appears once every four field periods, that is, once every rotation period of the rotating recording medium to be recorded. On the other hand, the monostable multipipulator 12 is triggered by the front line (falling edge in this embodiment) of the output pulse of the gate circuit 9, and outputs the pulse from which effects such as equalization pulses within the vertical blanking period have been removed to the flip-flop. 13.

As a result, the flip-flop 13 outputs from its Q and Q terminals pulses that are mutually opposite in phase and inverted every four fields, and guide them to output terminals 16 and 17. This output terminal 16,
The 17 output pulses Q and Q are applied to a pulsed oscillator (not shown) that oscillates and outputs reference signals Nap, P2 used for tracking control, respectively, and the oscillation operation is performed every 4 field periods. Do it alternately. The reference signals 〆p, 〆p2 have different frequencies, and are selected, for example, from a lower frequency band than the main track recording signal band, and are connected to a light beam modulator (not shown), for example.
The incident optical path of this light beam to an objective lens (not shown) is adjusted so that the main track is alternately converted into a modulated light beam every rotation period (here, every 4 field periods) of the rotating recording medium. Recording is performed by forming a sub-track as a change in geometrical shape approximately in the middle between adjacent tracks. Therefore, although the track pattern on the rotating recording medium to be reproduced by the method of the present invention is not shown in the drawings, as previously disclosed by the applicant in Tokiso Sho 51-Chichibura No. 09, a needle guide groove is used. A spiral or concentric main track on which at least a frequency-modulated video signal is recorded as a change in geometrical shape on a rotating recording medium having a flat surface; , 〆p2 sub-tracks, and in the present invention, further sub-tracks of Nap,, Nap2
A signal of at least one of a gray level and a single frequency (sine wave) is applied once every round in part or all of the vertical line erasing period of the recorded video signal of the main track corresponding to the recording switching position. (However, the example shows a case where both gray level and single frequency are inserted and recorded).

Note that it is possible to detect the recording switching position on the Na side and Nap2 only by inserting the gray level recording, but from the S/N perspective, it is better to record a single frequency because it allows the use of the Obishiro amplifier in the playback system, which will be described later. is advantageous.

Furthermore, when recording both the gray level and a single frequency, it is possible to use up to the maximum recording capacity of the amplitude of the video signal to be recorded, which is advantageous in terms of S/N. FIG. 3 shows a block system diagram of the main parts of a second embodiment of the recording system according to the present invention.

In the figure, the same parts as in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted. In the embodiment shown in FIG. 1, NaM and Mep2 are recorded during the vertical blanking period in which the detection signal indicating the switching recording position of Nap2 on the Na side of the reference bond is recorded. However, in reality, depending on the timing of switching, etc., it is advantageous for the Na side Na p2 not to exist during the detection signal insertion period. This embodiment satisfies the above requirements, and includes gate circuits 18 and 19 that gate the Q and Q outputs of the flip-flop 13, so that the output pulse of the monostable multipipulator 12 is shared as the gate pulse of the gate circuits 18 and 19. It is configured to do so.

Here, the pulse width of the output pulse of the monostable multi-pipelator 12 is approximately the same as the pulse width of the output pulse of the width-adjusting monostable multi-pipelator 7 shown in the first figure. The gate circuits 18 and 19 are kept "closed" only during this pulse width period. Therefore, although the output terminals 20 and 21 of the gate circuits 18 and 19 have a period of 4 fields, no pulses are outputted only during the detection signal insertion period. All oscillation operations are stopped. Next, the reproducing system according to the present invention will be explained with reference to FIG. 4, which shows a block system diagram of an embodiment of the main part of the reproducing system according to the present invention. Detecting changes in the intensity of reflected (or transmitted) light from a light beam, detecting changes in capacitance, or detecting temporal changes in mechanical vibration, etc. from a rotating recording medium recorded by the recording system shown in FIG. 1 or 3. A reproduction signal from the main track reproduced by a well-known pickup means is sent to a demodulator (not shown).
After being demodulated into a video signal by
The signal is supplied to the synchronizing signal separation circuit 23 and the gate circuit 26, respectively. It should be noted that the above-mentioned pickup means can perform stable tracking control operation by a closed loop servo in addition to a tracking rut control circuit (not shown) by discriminating and reproducing the 〆p and/or 2 included in the reproduction signal. This is already disclosed in Japanese Patent Application No. 51-38809. The synchronization signal separated by the synchronization signal separation circuit 23 is separated by the vertical synchronization signal separation circuit 24 and supplied to the gate pulse generator 25, which is connected to the recording system and the same machine by a monostable multi-noise brake. A gate pulse with a period of 4 fields is generated.

This gate pulse is supplied to the gate circuit 26 and kept in the "open" state only during the detection signal insertion period. Therefore, the output of the gate circuit 26 receives the vertical pulses in the reproduced video signal input from the input terminal 22 at a period of 4 fields. A sine wave of a single frequency that has been superimposed on IH or several days during the female line erasure period is extracted. This sine wave is selectively regenerated by a narrowband band amplifier 27 having a center frequency of a passing frequency band at a frequency equal to the oscillation frequency of the pulsed oscillator 10, and then a detector 2
After being detected at step 8, it is applied to flip-flop 29 as a trigger pulse. Therefore, a pulse that is inverted every rotation period of the rotating recording medium is taken out from the flip-flop 29, and this pulse is used as a pulse for switching the input from the output terminal 30 to the tracking control circuit of p, p2. . Note that if only the gray level is superimposed on the video signal as a detection signal, a circuit that detects the DC level may be used instead of the band amplifier 27.

In this way, the recording switching position of the closing side p2 can be detected purely electronically by the output pulse of the output terminal 30, and the tracking error voltage can be inverted.
Note that a pseudo video signal such as a signal obtained by converting an audio signal into a signal format similar to a video signal by PCM, for example, also belongs to the same category as the video signal referred to in this specification.

As described above, the information signal recording and reproducing method according to the present invention records at least one of a gray level signal and a single frequency signal within the vertical blanking period of a frequency-modulated video signal, which is a main information signal. A spiral or D-circular main track is formed as a change in geometrical shape by superimposing the video signal once every round, and is recorded on a rotating recording medium, and between each track of the main track. First and second reference signals of different frequencies are placed approximately in the middle of the image signal in a geometric shape for each rotation period of the rotating recording medium, with the position corresponding to the recording of the vertical erasure period of the video signal being the recording sliding position. The first and second changes are recorded alternately during playback.
The reference signals of the first and second reference signals are differentially reproduced and used as a tracking control signal, and the signals superimposed within the vertical female line erasure period of the video signal are input to the tracking control circuit. This allows switching to be performed purely electronically without adversely affecting the video signal.
The switching position of the second reference signal can be detected, and by using a narrow-band amplifier during reproduction, the superimposed signal can be stably reproduced even if the S/N of the demodulated video signal deteriorates. Moreover, since the gray level or single frequency signal or both signals are continuously superimposed for a certain period within the 0 vertical women's erasure period, the effect of dropout can be almost ignored. It has the following.

1 is a block system diagram of the first embodiment of the recording system according to the present invention, FIGS. 2A to 2 are signal waveform diagrams for explaining the operation of FIG. 1, and FIG. FIG. 4 is a block system diagram of main parts of a second embodiment of a recording system according to the invention, and FIG. 4 is a block system diagram of an embodiment of a reproduction system according to the invention.

1... Video signal input terminal, 3, 24... Vertical synchronizing signal separation circuit, 4, 5, 13, 29... Flip flip.

Tup, 8...J-K flip-flop, 9, 18, 19
, 26... Gate circuit, 10... Pulsed oscillator, 11... Inverting amplifier, 12...
・… Monostable multipipulator, 16, 17….・・・
Reference signal output terminal, 22... Demodulated video signal input terminal, 27... Bandwidth amplifier. Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Claims] 1. During the vertical blanking period of the frequency-modulated video signal, which is the main information signal, at least one of the gray level and single frequency signals is superimposed once every round, and the geometric A spiral or concentric main track is formed as a change in the shape of the main track and is recorded on a rotating recording medium, and first and second references of different frequencies are provided approximately in the middle between each track of the main track. The signal is alternately recorded as a change in geometrical shape every rotation period of the rotary recording medium using the recording switching position corresponding to the vertical blanking period of the video signal, and during reproduction, the first and second The second reference signal is differentially reproduced and used as a tracking control signal, and the first and second reference signals are input to the tracking control circuit by discriminating the signal superimposed within the vertical blanking period of the video signal. An information signal recording and reproducing method characterized in that switching is performed by reproducing.