FR2513789A1 - ROTATING RECORDING MEDIUM - Google Patents

Abstract

THE RECORDING MEDIA SHOWS A RECORDED AUDIO SIGNAL SUCH AS A TRACK INTERVAL (V9-A, V13-B, V17-C ..., I-V3, J-V7, K-V11 ...) INCLUDING A TRACK POSITION IMMEDIATELY BEFORE A POSITION WHERE THE READING ELEMENT OF THE DISC IS OFFSET IN RESPONSE TO A JUMP COMMAND SIGNAL, AND A TRACK INTERVAL (V9-A, V13-B, V17-C .. ., I-V3, J-V7, K-V11 ...) INCLUDING A TRACK POSITION IMMEDIATELY AFTER THE POSITION WHERE READING IS SHIFTED BY THE JUMP CONTROL SIGNAL INCLUDING THE SAME CONTENT.

Description

The present invention relates generally

  rale of rotating recording media, and it relates more particularly to a rotating recording medium from which a jump signal recorded on the medium is reproduced by a reading element and the element

  is shifted (caused to jump) to an adjacent track

  cente in order to reproduce video and audio signals in a reproducing apparatus, the audio signal being recorded

  in such a way that the reproduced sound does not become inconsistent.

  continuous even when the reading element is shifted.

  A new device for recording and / or reproducing information signals has been described in US Pat. Nos. 4,315,283 and 4,322,836. According to the device of these patents, the recording assembly forms hollows in accordance with a information signal recorded along a spiral track on a flat rotating recording medium (hereinafter referred to simply as a disc) without forming a

  grooves In the reproduction set, a play style

  ture follows this track to reproduce the informational signal

  tion recorded in response to variations in electrostatic capacitance. In such a device, since no guide groove is provided on the disc to guide the reading style, it becomes necessary to record, on the disc, pilot or reference signals on, or

  in the vicinity of a track of a pro-

  gram During playback or playback, the reference signals are played back, i.e. read, together with the program information signal. A track follow command is performed in such a way that the style read precisely tracks the track in response to signals

of reference reproduced.

  The use of the above device means that there is no possibility whatsoever, both for the playing style and for the disc to be damaged due to

  that the recording track has no grooves.

  The reading style can follow the same part of the track.

  repeatedly several times, so that it becomes pos-

  likely to make a reproduction of a particular type,

  such as a freeze frame reproduction, a reproduction

  tion in slow motion or accelerated reproduction, in case the recorded information signal is a video signal.

  In order to perform partial type reproduction

  culier above, a jump pulse is produced by

  a particular reproduction mode control circuit

  link, and this jump pulse is applied to a bo-

  Tracking control unit of a playback device

  signal style, to shift the playback style to an adjacent track Because the track is formed in a spiral shape, when playing back in slow motion, for example, the playback style is shifted to a track adjacent in the direction of the outer periphery of the disc, once for each revolution of the disc During

  slow-motion playback, reading style is shifted

  to an adjacent track in the direction of the outskirts

  external rie of the disc, once for a given number of revolutions of the disc, starting from one revolution In addition, during an accelerated reproduction, the reading style is shifted towards a track in the direction of the internal periphery

of the disc.

  Consequently, the particular mode of reproduction

  bind known above was previously obtained in effect

  killing freeze frame playback, slow motion playback, and time lapse playback, relative to a portion of a continuously recorded program

  on the tracks formed on the disc.

  However, there is now an increased demand

  to record and reproduce various information programs

  mationson a disc It is therefore highly

  desirable to make a new reproductive system

  particular tion to obtain a particular image

  such as an image obtained by composing different

  recorded information and an image obtained by choosing-

  health information from a set of information

registered -

  The present invention therefore aims to produce a new disc which satisfies the above requirements.

  thus sought to make a disc recorded in present

  both a jump signal in predetermined positions to shift the playback element to an adjacent track

  to be able to choose, appropriately, different

  rents sets of video information of programs recorded on each track according to the jump signal obtained during playback in order to obtain a reproduced image However, it has been found that in such a disc, if the audio signal was recorded in a normal manner , a problem existed because a discontinuity was introduced in the audio information reproduced when the information program

  program video above is selectively reproduced

  tive So if the reading element is shifted inside

  a vertical erasure period of the recorded video signal

  very on the track, no harmful phenomenon appears in

  the reproduced image obtained by means of the reproduced video signal

  due to the above offset Certain discontinuities

  are however introduced into the audio signal.

  The present invention thus relates to a rotating recording medium which is new and particularly useful and in which the drawbacks described above have been overcome; a rotating recording medium from which a jump pulse recorded on the medium is

  reproduced by a reading element, and this reading element

  ture is shifted (caused to jump) to an adjacent track so

  to reproduce video and audio signals in a Dro-

  duction, the audio signal being recorded in such a way that the

  its reproduced does not become discontinuous even when the element

  Playback is offset According to the rotating recording medium of the present invention, identical audio information contents (including an audio silence signal) are recorded on adjacent tracks during a predetermined interval of each of the tracks. playback device is shifted to the ad-

  in order to avoid discontinuity in the content of information

audio signal.

  Various other features of the invention res-

  emerge from the detailed description which follows.

  Embodiments of the subject of the invention are shown, by way of non-limiting examples.

attached drawing.

  Fig 1 is a block diagram of an embodiment of a recording device for a disc

according to the present invention.

  Figs 2 A and 2 B respectively represent waveforms of a jump control signal recorded on

the disc.

  Fig 3 illustrates a first form of realization

  sation of a track diagram formed on the conforming disc

to the present invention.

  Fig 4 is a block diagram of an embodiment of a reproduction apparatus for reading

the disc illustrated in fig 3.

  Fig 5 illustrates a second embodiment of a track diagram formed on the disc according to the present invention. Fig 6 is a block diagram of an embodiment of a reproduction apparatus for reading

the disc illustrated in fig 5.

  Fig 7 is a block diagram of a concrete embodiment of a circuit for controlling the diagram

overview of fig 6.

  Figs 8 (A) to 8 (E) respectively illustrate waveforms of the control circuit output signal

illustrated in fig 7.

  We will now describe, with reference to FIG. 1 in the form of a block, an essential part of a form of

  creation of a recording device enabling

  record signals on a disc according to the present invention First and second channel audio signals are independently applied to input terminals 11 and 12 The first channel audio signal is applied to a frequency modulator 16 in which an audio signal FM of the first channel is obtained by frequency modulating a carrier wave having, for example, a frequency of 3.43 M Hz. Furthermore, the audio signal of the second channel is applied to a frequency modulator 17 in which an audio signal MF of second channel is obtained by frequency modulating a wave

  carrier having, for example, a frequency of 3.73 M Hz.

  The above first and second channel MF audio signals are applied to a mixer circuit 18 respectively. A video signal applied to an input terminal 13 is triggered by a door pulse at a door 19 Such a door pulse is applied to an input terminal 14 together with a jump control signal which is

  applied to an input terminal 15 which will be described later.

  As a result, the above video signal is cleared of the video signal recording interval beyond a color burst signal within a period of

  horizontal scan, and it is applied to a mixing circuit

  geur 20 The mixing circuit 20 mixes the video signal leaving the door 19 and the jump control signal obtained on the input terminal 15 and inserts the jump control signal in the recording interval - of the cleared video signal above, and it applies the mixed video signal

  to the melting circuit 18 The mixed video signal is multi-

  tripixed to the FM audio signals of the first and second channels at the mixing circuit 18 Measures are taken so that the band of the video S 4 nal applied to the input terminal 13 does not overlap the bands of the FM audio signals of the first and second channels For example, the above video signal is a composite color video signal in which a chrominance carrying signal whose frequency is converted into the low band is subjected to band sharing multiplexing with a high frequency range of one luminance signal whose frequency band is limited to one

approximately 3 MHZ higher.

  The jump control signal above is a burst signal having a frequency of 500 K Hz, for example, and it is multiplexed with the video signal at the level of the mixer circuit 20 as illustrated in FIG. 2 A

  jump control signal B includes five pieces of information

  binary or bit mation A first bit B 1 of the com-

  jump command B indicates if the jump operation is to be performed In case the first bit is "1" (saved), the jump operation is performed, and, if the first bit is

  "O" (not registered), the jump operation is not performed

  killed A second bit B 2 indicates the direction of the jump, and "1" indicates the direction of the external periphery of the disc, while "O" indicates the direction of the internal periphery

  Third and fourth bit B 3 and B 4 indi-

  which mode of reproduction is used, and four modes of reproduction can be specified by setting these bits to "00", "01", "10" and "11" In this case, "00" indicates a first mode, "01 "indicates a second mode and" 10 "indicates a third mnde A fifth bit B 5 indicates the number of hops If the first bit Bl is" 1 "," 0 "in the fifth bit B 5 indicates a single jump and

  "1" in this fifth bit B 5 indicates two jumps The signal of com-

  jump command B exists between horizontal synchronization signals

  HD and HD rate, in an interval where the color burst signal CB does not exist In the example of fig 2 B, the first bit Bl is "1", the second bit B 2 is "O", the third bit B 3 is "1", the

  fourth bit B 4 is "O" and the fifth bit B 5 is "1".

  This indicates that the jump has been made, that the jump is directed in the direction of the periphery: internal of the disk, that the reproduction mode is the third mode, and that

  the number of jumps is equal to two.

  The multiplexed signal obtained at the output of the mixer circuit 18 is applied to a frequency modulator 21

  o the signal is converted into a wave with frequency modulation

  quence with a carrier deviation bandwidth of 6.1 M Hz to 7.9 M Hz, for example The frequency modulated signal is produced on an output terminal 22 in

  as the main information signal.

  The main information signal above is applied to a light modulator (not shown), for example, and it is converted into a modulated light beam by modulation of a laser light. The modulated light beam is focused on a photosensitive agent applied to a

  original disc or matrix and which is rotated.

  Through a known development process,

  a main runway with rows of inter-

  mittents is formed on the disc according to the frequency of rotation of the main information signal Thus, the video signal and the audio signal of the two channels are respectively

  and simultaneously recorded on the same main track.

  First and second reference signals fp I and fp 2 of

  tracking control are applied to another modu-

  light erector (not shown) and analogously converted into a light beam modulated by modulation of a laser light Thus, sub-tracks having rows of intermittent pits are formed between the main tracks The disc is made by the through a known manufacturing process, from the original disc or

matrix saved above.

  As illustrated in FIG. 3, a disc 30 produced in the manner described above is recorded by presenting the main information signal on a spiral track T for one revolution of the disc. The tracks of the first reference signal úpl are represented by broken lines. , while the tracks of the second reference signal fp 2 are shown in dashed lines The position of the vertical synchronization signals of respective frames is designated by the references Vl, V 2, V 3 ,, and the parts of successive tracks corresponding to a disc turn of a single spiral track T are designated by turns ti, t 2, t 3

  In addition, a third reference signal fp 3 is recorded.

  very in an extreme starting position VI, V 5, V 9, of each of the turns ti, t 2, t 3 ,, that is to say at the level of

  positions where the reference signals fpl and fp 2 switch.

  In an interval between positions VI

  and V 9 (such an interval will hereinafter be called interval VI-

  V 9), a program has been recorded on the spiral track of the disc which presents a problem and provides X, Y and Z answers from which the given answer must be chosen, for example a program allowing to give a comment on the answer when the answer X is chosen, is recorded in the intervals V 9-V 13 and V 21-V 25 according to the above program In a similar way, programs allowing to give comments on the answer when

  the answers X and Z are chosen, are respectively recorded

  stored in intervals V 13-V 17 and V 25-V 29 and inter-

  valles V 17-V 21 and V 29-V 33 A program allowing to present

  ter a successive problem is continuously recorded towards the internal periphery of the disc from position V 33 A jump command signal containing the information "1010 V" as illustrated in fig 2 B is recorded at position V 9 to indicate two jumps towards the internal periphery of the disc in the third mode In addition, a jump control signal containing the information "1000" is recorded at a position p to indicate a jump towards the internal periphery of the disc in the second mode Similarly, jump control signals are recorded at positions V 13, V'17, V 21 and V 25 to indicate two jumps to the internal periphery of the disc in

  the first mode, the second mode, the third mode and, respec-

  the first mode In addition, a jump signal is

  recorded at position V 29 to indicate a direction jump

  tion of the internal periphery-of the disc-in the second mode.

  The audio signal is continuous for each program.

  During an interval in which the play style is shifted (caused to jump) to an adjacent track at an interval immediately after position V 9 where the jump is made via the jump control signal recorded at position V 9 for example it is

  essential that the audio signal does not become discontinuous.

  Consequently, in the present invention, the same

  audio signal or the same audio silence signal (i.e.

  say the audio signal is not recorded) is recorded

  very in intervals V 9-a and V 17-c In addition, depending on the mode in which the jump is made via the jump control signal recorded at the position AT

  the same audio signal as that recorded in the inter-

  valle V 9-a or the silence audio signal is recorded in an interval V 13-b, so that no discontinuity

  is introduced between the intervals V 9-a and V 13-b.

  In addition, and for analogous reasons, the intervals V 9-a, V 13-b, V 17-c, V 21 l-d, V 25-e, V 29-f, V 33-g, are

  all intervals of silence, for example.

  An embodiment of a reproduction apparatus will now be described with reference to FIG. 4

  allowing to read the disc 30 illustrated in fig 3.

  The disc 30 is placed on a plate 31 and it is rotated by a motor 32 at a speed, for example, of 900 revolutions per minute. A device 33, for reading signals used as a reproduction transducer, has a style 34, and moves, continuously and linearly, from the external periphery of the disc towards its internal periphery at a speed equal to one track step per revolution of the turntable 31, during a reproduction mode At normal forward speed As a result, the reading style 34 of the signal reading device 33 moves radially on the disc 30 in the process of spinning and scans, for a certain distance, the spiral track

formed on disk 30.

  A signal read from disk 30 in the form of very small variations in electrostatic capacitance

  using play style 34 of the playback device

  The signal frequency 33 is applied to a preamplifier 35 having a resonant circuit. The resonant frequency of the resonant circuit varies in response to the above variation of the electrostatic capacitance, and it provides a desired level signal. The resulting signal output of the pre-amplifier 35 is demodulated to form the original main information signal by a demodulator 36, and is obtained as

  output signal on an output terminal 37.

  The output signal of the preamplifier 35 is applied to a low-pass filter 38 in which the reference signals fpl, fp 2 and fp 3 are separated.

  reference signals coming out of the low pass filter 38 tra-

  pour an automatic gain control circuit 39 and they are respectively applied to amplifiers

  , 41 and 42 In the present case, each of the amplifiers

  cateurs 40, 41 and 42 is a kind of pass amplifier

  band each designed to exhibit characteristics of

  peak passing frequency for the respective frequencies

  tives fpl, fp 2 and fp 3 only Thus, the signals having frequencies fpl and fp 2 are respectively separated and obtained at the output of amplifiers 40 and 41 These signals pass through level regulators 43 and 44 respectively where the levels of signals are set The resulting signals are then applied to a door switching device 45 The reference signal fp 3 separated and amplified by the bandpass amplifier 42 is applied to a signal generator

switching 46.

  The door switching circuit 45 switches the reference signals fpl and fp 2 to

  each period of rotation of the disc 30 during a repro-

  duction at normal speed, in response to the com-

  mutation formed by the switching signal generator 46 which is applied to it Thus, due to the switching signal which reverses its polarity every 1/15 second, the signals fpl and fp 2 are always applied alternately to detection circuits 47 and 48 from

  of the door switching circuit 45.

  The detection circuits 47 and 48 detect the

  envelopes of their respective input reference signals

  tifs, and transform these input reference signals into direct current voltage 'These current voltages

  are then applied to a different amplifier

  ferential 49 The differential amplifier 49 compares the output signals of the two detector circuits 47 and 48 which vary in response to the reproduced levels of the reference signals fpl and fp 2, and this amplifier forms a tracking error signal which indicates the direction of the tracking error and the value of that error Such a tracking error signal

  track is amplified at a particular level by an ampli

control link 50.

  The control amplifier output signal

  is applied to track tracking coils of the device

  positive reading of signals 33 in the form of a control signal in order to control these tracking coils The tracking control is thus performed with respect to the reading style 34 so that the tracking error signal above track becomes null, i.e. so that the play style 34

  precisely scans the track T formed on the disc 30.

  The output signal of the demodulator 36 is applied to a detector 51 of the jump control signal in which the demodulated jump control signal is detected at the same time as the video signal The jump control signal thus detected is applied to a switch 52 The selector switch 52 allows

  go through and provide a predetermined type of com signal

  jump command to a jump pulse generator 54 among the control signals obtained at the output of the detector 51, according to a setting made at the selection switch 52 by means of a setting signal coming from a terminal 53 The jump pulse generator 54 creates a jump pulse for performing a jump operation in the direction of the internal periphery or the external periphery of the disc according to the type of jump control signal obtained by the switch intermediate

  selection 52 The jump impulse thus formed-is ap-

  plied to the track-following control coils of the signal reading device 33 via the control amplifier 50 The reading style 34 is thus caused to jump towards the internal periphery or the external periphery of the disc , and it is thus shifted to an adjacent track In addition, the jump pulse from the jump pulse generator 54 is also applied to the switching signal generator 46, so that a switching signal is formed and qu '' it is applied to the circuit

door switch 45.

  When the disc 30 illustrated in FIG. 3 is read by the reproduction apparatus illustrated in FIG. 4,

  the operator solves the problem presented while repro-

  dividing the interval V 1-V 9 If the operator wishes to choose the response X as the response for this problem, for example, a movable contact of the switch 52 is

  connected to a contact 52 a to choose the first mode below

  above Reading style 34 reproduces the recorded information (the content of the information is a problem) in the interval V 1 -V 9, and it begins to scan the

  track t 3 without having to jump to position V 9.

  Then, the reading style 34 scans the interval V 9-V 13 and reproduces the commentary on the response X. After the scanning of the interval V 9-V 13, the reading style 34 is caused to jump twice to position V 13, then it scans the interval V 21-V 25 in order to continue reproducing the commentary on response X The reading style 34 is caused to jump twice to position V 25 and reaches position V 33, and, from there, it begins to read the following problem In this case, the reading style 34 is caused to jump twice at positions V 13 and V 25, and it is shifted to positions slightly beyond the positions V 21 and V 33 However, since

  1 o the intervals V 13-b and V 21-d are respectively recorded

  very by presenting the same audio or silence signal and that the intervals V 25-e and V 33-g are likewise recorded by presenting the same audio or silence signal as described above, no discontinuity is introduced in the

  is content of the audio signal reproduced during the above shift

above reading style 34.

  When choosing the response Y, the movable contact of the switch 52 is connected to a contact 52 b to choose the second mode above. In such a case, the reading style 34 is caused to jump once to the position p after have read the problem in the interval V 1 -V 9, and it

  scans the interval V 13-V 17 in order to reproduce the beginning

  be silent on answer Y After having reproduced the

  valle V 13-V 17, the reading style 34 is caused to jump

  twice at position V 17, and then it continues to re-

  produce the comment on answer Y by scanning the

  tervalle V 25-V 29 The reading style 34 is made to jump once to position V 29 to reach position V 33, and from there it begins to read the following problem In this case, the reading style 34 is made to jump once at positions p and V 29 and twice at position V 17 However, since the intervals V 9 -a and V 13-b are recorded by presenting the same audio signal or

  silence, that the intervals V 17-c and V 25-e are recorded

  very by presenting the same audio or silence signal, and that the intervals V 29-f and V 33-g are recorded by presenting the same audio or silence signal, no discontinuity is introduced into the content of the audio signal reproduced at during the style shift of

reading 34.

  When choosing the response Z, the movable contact of the switch 52 is connected to a contact 52 c to choose the third mode above. In such a case, the reading style 34 is caused to jump twice to the position V 9 after having read the problem of the interval V 1 -V 9, and it

  scans the interval V 17-V 21 in order to reproduce the beginning

  silence on the Z response After having reproduced the interval V 17-V 21, the reading style 34 is caused to jump twice to the position V 21, and then it continues to reproduce the commentary on the Z response by scanning the interval V 29-V 33 The reading style 34 then reaches the position

  V 33, and from there he begins to read the next problem.

  In this case, the play style 34 is caused to jump twice at positions V 9 and V 21 However, because the intervals V 9-a and V 17-c are recorded with the same audio or silence signal and that the intervals V 21-d and V 29-f are recorded presenting the same audio signal or of silence, no discontinuity is introduced into the content of the audio signal reproduced during the style shift

reading 34.

  We will now describe, with reference to FIG. 5, a second embodiment of the disc according to the present invention. In FIG. 5, the elements which are the same as the elements corresponding to FIG. 3 are designated by the same references and do not will not be described in detail in the following In a disc 60, a video signal of a first program is recorded in an interval V 1 -V 3, that is to say from the position V 1 to the position V 3 on the

  track t I A video signal from a second program presents

  as long as different content of the first program is recorded in an interval V 3-V 7 Similarly, the first program is recorded in the intervals V 7-V 11, V 15-V 19, V 23-V 27 ,, and the second program is recorded in intervals V 11-V 15, V 19-V 23, The video signal of the first program is reproduced in the order of intervals V 1-V 3, V 7-V 11, V 15-V 19 , and it becomes continuous Similarly, the video signal from

  second program is reproduced in the order of the

  valles V 3-V 7, V 11-V 15, V 19-V 23, and becomes continuous.

  With regard to the audio signals, these are recorded as indicated below. First, the audio signal of the first channel is recorded in the following manner. The audio signal of the first channel having content corresponding to the video signal of the first program in intervals V 1-V 3 and V 7-k, is recorded in an interval VI-j extending to position j at 1.5 frames beyond position V 5 from position V 1 , via positions i and V 3 to V 6 The audio signal of the first channel having content corresponding to the video signal of the first program in intervals iV 3 and V 7-k, ie the same audio signal as that of an interval ij, is recorded in an interval jk Consequently, the content of the signal

  audio of the first channel is discontinuous at position j.

  An audio signal corresponding to the content of the video signal in intervals k-V 11 and V 15-m and which is continuous with the audio signal in the interval j-k

  at position k, is recorded in an interval k-1.

  An audio signal that is the same as that recorded

  in the interval k-l is recorded in an inter-

  valle l-m, and the content is discontinuous at position 1.

  In addition, an audio signal which is continuous with the audio signal recorded in the interval 1-m at the position m is recorded in an interval min. A signal

  audio, which is the same as that recorded in the inter-

  valle m-n, is recorded in an interval n-o.

  The audio signal of the second channel is recorded in the following manner The audio signal of the second channel corresponding to the content of the video signal of the second program is recorded in the interval V 3-V 7 An audio signal which is the same as the corresponding audio signal to the video signal in the interval V 11-l is recorded in an interval V 7-k Likewise, the audio signal recorded in the interval k-1 is the same as the audio signal recorded in an interval jk In addition, the audio signals recorded in intervals kl and 1-k correspond to video signals recorded in intervals 1-V 15 and V 19-n The audio signal of the second channel is discontinuous at the positions

k and m.

  An embodiment of a reproduction apparatus

  duction allowing to reproduce or read the disc 60 above is illustrated in fig 6 In fig 6, the

  elements which are the same as the corresponding elements

  dants of fig 4 are designated by the same references

  and will not be described in detail in the following.

  The first and second channel audio signals obtained from the demodulator 36 are respectively

  applied to contacts 61 a and 61 b of a switch 61.

  A movable contact of the switch 61 is switched and connected to one of the contacts according to a mode specifying signal applied to an input terminal 62 Thus, if the signal coming from the input terminal 62 is a specifying signal of the first mode , the movable contact of the switch 61 is connected to the contact 61 a Furthermore, if the signal coming from the input terminal 62 is a signal specifying the second mode, the movable contact of the switch 61 is connected to the contact 61 b The audio signal of the first and second channel which is selectively passed through the switch 61 is obtained

on an input terminal 63.

  A mode specifier signal identical to that applied to input terminal 62 is applied to a

  control circuit 64 from an input terminal 65.

  If the program video signal to be selected

  is the signal of the first program, the specific signal

* cator of the first mode is applied to the input terminal Furthermore, if the program video signal to be chosen is the signal of the second program, the signal specifying the second mode is applied

at input terminal 65.

  The control circuit 64 has, for example,

  an embodiment similar to that illustrated in fig 7.

  An oscillating output signal from an oscillator 70 is

  applied to a counter 71 as a clock pulse

  The counter 71 also receives on a terminal 72

  the third reference signal fp 3 from the am-

  plifier 42 as a reset signal The output signal from the counter 71 is applied to a decoder 73 Signals P and Q respectively illustrated in FIGS. 8 (A) and 8 (B), which are obtained at the output of the

  decoder 73, are applied to a contact q of a

  mutator 74 Inverted signals P and Q illustrated

  pectively in fig 8 (D) and 8 (E) which are obtained by inverting the signals P and Q at the level of inverters 75 a

  and 75 b are applied to a contact r of the switch 74.

  A movable contact of switch 74 is switched and connected to contact _ or r according to the first or second mode specified by the mode specifier signal from terminal 65 The signals P and Q are obtained at output terminals 76 a and 76 b during the first mode, and the signals P and U are obtained at the output terminals 76 a and 76 b during the second mode The above signals obtained at the output terminals 76 a and 76 b are respectively applied to the door switching as door switching signals In addition, a signal R illustrated in fig 8 (C) is obtained at the output of the decoder 73 and produced on an output terminal 76 c Le

  signal R above is applied to a pulse generator

  Jump Sions 54 which forms a jump pulse allows

  both shift the reading style 34 by one track step.

  When the video signal of the first program and the audio signal of the first channel corresponding to this video signal of the first program are reproduced, the signal specifying the first mode is applied to the input terminals 62 and 65 In this state, the playback style 64 reproduces the information recorded in the interval V 1-V 3 and it is made to jump once to the position V 3 Then, the reading style 34 scans the interval V 7-V 11 and is made to skip a times at position Vil Reading style 34 then scans the interval V 15-V 19 and is made to jump once at position V 19 Scanning by reading style 34

  then continues in an analogous manner It results from-

  the above that the intervals V 1-V 3, V 7-Vt 1, V 15-V 19, are reproduced continuously The video signal of the first program is obtained on the output terminal 37, and the audio signal of the first channel corresponding to the above video signal of the first program is obtained on the output terminal 63 The reading style 34 is caused to jump once and is shifted to the positions V 3, Vil, V 19, however, as described above , the audio signal of the first channel recorded in the interval id-j is the same as the audio signal recorded in the interval jk Likewise, the audio signals recorded in the intervals kl and 1-m are the same, and the signals audio recorded in

  intervals m-n and n-o are the same No disconti-

  noise is therefore introduced into the continuous audio signal reproduced when the playback style 34

is shifted.

  Furthermore, during the reproduction of the video signal of the second program and of the audio signal of the second channel corresponding to the video signal of the second program, the signal specifying the second mode is applied to the

  input terminals 62 and 65 The reading style 34 repro-

  duces the information recorded in the interval V 3-V 7 and is made to jump once to the position V 7 Then, the reading style 34 scans the interval V 11-V 15 and is made to jump once to position V 15 The reading style 34 then scans the interval V 19-V 23 and is made to jump once to the position V 23 The scanning by the reading style 34 then continues in an analogous manner It results from what precedes that

  the intervals V 3-V 7, V 11-V 15, V 19-V 23, are repro-

  continuously output The video signal of the second program is obtained on the output terminal 37, and the audio signal of the second channel corresponding to the video signal of the second program above is obtained on the output terminal 63 The playback style 34 is caused to jump once and is shifted to the positions V 7, V 15, V 23, However, as described above,

  the audio signal of the second channel recorded in the inter-

  valle j-k is the same as the recorded audio signal

  in the interval k-l Similarly, the audio signals

  recorded in the intervals 1-m and m-n are the same, and the audio signals recorded in the interval n-o and in the interval continuing one turn of the disc

  60 are the same No discontinuity is, therefore,

  quence, introduced into the content of the audio signal

  reproduced when reading style 34 is shifted.

  The invention is not limited to the embodiments shown and described in detail since various modifications can be made thereto without departing from

its frame.

Claims (4)

  1 revolving recording medium read by a reproduction apparatus which has a reading element making it possible to reproduce or read signals recorded from a revolving recording medium, said revolving recording medium presenting video signals of different programs recorded for each predetermined interval on a spiral track formed on the disc, a jump control signal (B) recorded at an extreme part of said predetermined interval making it possible to shift the reading element towards another turn, and a audio signal recorded on the medium, characterized in that said audio signal is recorded in such a way that a track interval (V 9-a, V 13-b, V 17-c, iV 3, jV 7, k-Vil ,) including a track position immediately prior to a certain position where the playback element is shifted in response to said jump control signal, and a track interval (V 9-a, V 13-b, V 17- c ,, iV 3, jV 7, k-Vil,), yc omitted a certain track position immediately after the position where the playback element is shifted, include the same content. 2 revolving recording medium according to claim 1, characterized in that the audio signal of the same content recorded in the track intervals is an audio signal of silence.   3 revolving recording medium according to claim 1, characterized in that the audio signal comprises different audio signal channels corresponding to the video signal programs, and in that the jump control signal is recorded at positions (V 9, V 13, V 17 ,, V 3, V 7, Vil,) on each turn of the spiral track so that the reading element is offset avoiding positions (a, b, c ,, ijk, ) o the contents of the audio signals of each channel become discontinuous if these contents are reproduced continuously. 4 revolving recording medium according to claim 1, characterized in that the jump control signal comprises a mode information (B 3, B 4) which determines which is the program video signal which must be selectively reproduced by the shift of the reading element.   Rotating recording medium according to claim 4, characterized in that the jump control signal further comprises information (B 5) indicating the number of times that the reading element must be shifted.