Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
  • G11B15/005—Programmed access in sequence to indexed parts of tracks of operating tapes, by driving or guiding the tape
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
  • G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
  • G11B27/102—Programmed access in sequence to addressed parts of tracks of operating record carriers
  • G11B27/107—Programmed access in sequence to addressed parts of tracks of operating record carriers of operating tapes
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
  • G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
  • G11B27/19—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier
  • G11B27/24—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by sensing features on the record carrier other than the transducing track ; sensing signals or marks recorded by another method than the main recording
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
  • G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
  • G11B27/19—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier
  • G11B27/28—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording
  • G11B27/32—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording on separate auxiliary tracks of the same or an auxiliary record carrier
  • G11B27/322—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording on separate auxiliary tracks of the same or an auxiliary record carrier used signal is digitally coded

Definitions

• the present invention relates to the automatic search for sequences recorded on any tape support, in particular in mini-cassettes.
• Such an automatic search is generally carried out by locating certain locations on the ribbon, which can then be accessed selectively.
• the difficulty is to carry out an automatic search which is both precise and reproducible on the one hand, fast and flexible on the other.
• rapid wear must be avoided by abrasion of the ribbon and / or the read heads. This requires very sonic arrangements, most of the time inapplicable to simple devices or fragile tapes such as those of mini-cassettes.
• the present invention allows an automatic search which satisfies the four conditions above, which is very simple, and which applies in all cases.
• the invention relates essentially to an automatic search device for recording sequences on a support tape, which applies particularly but not exclusively to sound recording on magnetic tape, and more specifically to recording on mini-cassettes.
• the device of the invention comprises, in combination:
• a motion sensor linked to one of the tape drive members, and capable of delivering electrical punctuation signals, according to a repetitive function of the movement of this member
• a reading circuit capable of reading on the ribbon specific brands, prerecorded on the ribbon to delimit successive sequences there, while defining an address for each sequence, as well as delivering for each mark read a main address signal sequence,
• a preselection circuit which receives this desired address signal in order to deduce therefrom an auxiliary address signal offset in a manner chosen in advance with respect to the desired address, means capable on command of producing a scrolling fast ribbon, while constructing an estimated address signal from a value of the main address which was read before the rapid scrolling and punctuation signals then delivered by the motion sensor, and this until what the estimated address signal corresponds to the auxiliary address, and
• a preliminary marking of the ribbon is thus used, which did not need This needs to be done strictly periodically on the tape. It suffices simply that this marking has a distribution whose deviations from the rigorous linearity are determinable.
• we make a kind of coarse positioning of the ribbon starting from an address already read on the ribbon with certainty during slow scrolling, and advancing this address according to the punctuation signals defined by a motion sensor related to the ribbon drive.
• the motion sensor is strictly linked to the linear speed of the ribbon drive, and the sensor can be mounted on a ribbon drive coil, the winding diameter of which varies, and whose consequently, the speed of rotation is not constantly linked to the speed of linear movement of the ribbon.
• the preselection circuit defines an auxiliary address whose offset is chosen taking into account the distribution chosen for the brands, as well as the way in which the motion sensor will deliver these punctuation signals as a function of the scrolling of the ribbon. Those skilled in the art will understand that under these conditions it is always possible to choose the auxiliary address signal so as to fall without fail upstream of the desired address on the ribbon, for example. Then, the ribbon is driven in slow movement while comparing the real addresses written in advance on the ribbon to the desired address, until the latter is obtained. The device has then reached exactly the desired sequence.
• the device of the invention may comprise a mark recording circuit, mounted between the sensor and the recording head, and capable, on command, of performing on the tape a preliminary recording of the sequence of marks, in correspondence with punctuation marks.
• This recording can be done at the same time as the recording of the useful signals, sound for example, or even separately.
• the apparatus can be used for playing mini-cassettes where the marks have been prerecorded at the same time as the useful signal or separately.
• the marks consist of digital pulse coding, or PCM, using bipolar pulses whose frequency is for example close to 600 Hz.
• the marks are recorded on one track and the audio signals on another. Marks recorded as indicated above at the level of - 15 dB are sufficient to allow the automatic search for sequences.
• the sensor is connected to the shaft of a ribbon drive coil, and provides all-or-nothing signals of closed or open contacts, depending on the rotation of this shaft.
• the reference numeral 10 generally designates a cassette recorder-player, comprising a supply reel 11 mounted on a shaft 110 and a take-up reel 12 mounted on a shaft 120. Between the two reels, the strip turns around two guide rods 131 and 132 which define a linear path portion where it comes into contact with a read recording head 13. There is provided in the linear part of the tape a means of driving the latter using a capstan, (not shown). Schematically, the tape running assembly is illustrated by block 16, which is in the separate drawing of block 10, and comes in mechanical cooperation with the two wound and the capstan.
• the recording-reading head 13 there is associated with the recording-reading head 13 a recording preamplifier 141 and a playback preamplifier 151.
• the same head reads the audio frequency signal on another track.
• a sensor 20 is mechanically linked to the take-up reel 12.
• the sensor comprises a shaft 210 connected for example by belt 211 to the shaft 120 of the take-up reel.
• the sensor itself is composed, like a coding wheel, of eight all-or-nothing contacts distributed evenly around the axis of rotation of the shaft 210. Thus, one in eight of the contacts will be closed for each angular position of the shaft and there is therefore obtained at the output of the sensor 20 a punctuation signal which is a function of the rotation of the shaft 210 and consequently of that of the shaft 120, at the rate of 8 points per turn.
• the output of the sensor 20, consisting of all or nothing signals, is shaped by a circuit 22 which makes the electrical punctuation signals compatible with TTL logic for example.
• a TTL logic counter, referenced 23, is capable of being connected by a contact 231 to the output of the shaping circuit 22, in order to receive the punctuation signals. These signals are applied to the counting input of the counter, which then allows them to advance the counter at the rate of 8 steps per revolution of the take-up reel.
• the parallel outputs representing the content of the counter 23 are applied using a plurality of contacts shown diagrammatically at 232 to a recording coding circuit 24 which energizes the preamplifier 141, so as to be able to record on the tape specific marks which delimit successive sections, while defining for each section an address depending on the state of the counter 23.
• the marks will be read by the head 13, and applied via the preamplifier 151 to a read decoding circuit 25 provided with an address buffer memory.
• a read decoding circuit 25 provided with an address buffer memory.
• the device includes a dead count 26, capable of being connected by a contact 261 to the output of the shaping circuit 22, and also of receiving the parallel outputs of the counter 23, which then serve to preload or hang the esteem counter.
• the output of the estimate counter 26 is connected to a comparator primary 271.
• the output of the reading decoding circuit 25 is connected to a secondary comparator 272.
• a control logic with direct access memory, or RAM, referenced 28 cooperates with the primary comparator circuits 271 and 272, as well as with the scrolling control circuit 16, in order to control the automatic search for recording sequences as a function of the indications given by an input device, such as a sequence selection keyboard 29.
• the logic also helps to define the state of the various switches, in particular 231, '232, 233 and 261.
• the present invention requires a preliminary inscription of the marks on the strip.
• This first step is carried out initially, before or during the recording on the tape of the sound signals, the contacts 231 and 232 being closed, under the effect of a preliminary recording signal EP which can be supplied by the logic 28, or by a separate command on the recorder-player.
• the strip then passes in slow movement, and the sensor 20 provides 8 successive punctuation signals for each revolution of the take-up reel. These signals are applied through the shaping circuit 22 to advance the counter 23, which then energizes the recording coding circuit.
• the latter then performs a coding of the content of the counter, in response to each change of state thereof, in the form of pulses with digital coding or PCM, pulses which are produced in bipolar form, and applied as modulation of a frequency of 600 Hz at the recording head 13.
• the detailed characteristics of this coding can be chosen from the recording codes well known under the name NRZ or even NRZm. So after wedging of the strip at the start of the strip, when it is practically entirely in the supply reel 11, marks are started on the strip which are linked to the change in state of the contacts of the sensor 20, and each bear a number.
• the marks will be progressively more and more spaced. However, marking at a rate of 8 steps per revolution is sufficient, even at the maximum winding diameter on the coil 12, in the majority of applications. If necessary, a sensor can be used with a greater number of marks per revolution, or even provide for subdivisions which will be recorded on the tape without being defined by the sensor itself, using an auxiliary counter circuit which would interpolate between changes counter 23.
• the switch 233 is closed, and the marks read as the tape runs are applied to the reading decoding circuit 25, which then directly controls the parallel inputs counter 23; provided with a digital display, this then permanently indicates to the user where the tape is running, in the manner of a conventional counter.
• the counter is directly linked to the running of the strip, and therefore provides highly repetitive indications, but which are not entirely regular depending on the running.
• the esteem counter 26 is loaded by the content of the counter 23 either permanently or only when a sequence search is to be carried out. Then, the switch 233 is open, and the counter 23 will no longer change state. The esteem account 26 therefore remains at the value previously defined during a slow-scrolling reading phase.
• the memory logic 28 then defines for the primary comparator 271 a coarse preset address, chosen so that it is certainly upstream of the desired address, for example by decreasing the desired address by a number preset.
• the switch 261 is then closed by the order of searching for the RSEQ sequences, so that the estimate counter now receives the pulses from the sensor 20 through the shaping circuit 22.
• the logic 28 then controls the member 16 so as to produce a rapid scrolling of the ribbon, scrolling during which the recording / reading head 13 is generally no longer in contact with the ribbon.
• the estimate counter is then updated using the sensor output pulses, and the rapid scrolling continues until the primary comparator 271 indicates to logic 28 that the content of the estimate counter corresponds to the coarse preset value.
• the fast scrolling is then stopped, and the logic 28 commands a slow scrolling, the read recording head 13 coming back into contact with the ribbon.
• the marks written on the tape can then be read in the usual way, and the reading decoding circuit 25 applies the marks to the secondary comparator 272.
• the logic 28 applies to this same comparator 272 the exact value of the desired address, and the slow scrolling continues until the comparator 272 indicates that the desired address has been reached, after which the logic 28 stops the scrolling members or continuously switches to the audio signal reading phase.
• the switch 233 is again closed, and the counter 23 then resumes the display of a precise indication as to the running state of the strip, from the marks actually read thereon.
• the present invention is susceptible of numerous variants easily accessible to those skilled in the art. It is for example easy to make a registration of marks on only part of the tape, which is in an initial phase alone intended to receive a recording, and to continue recording marks on the tape at the same time as the we complete the sound recording that she must wear.
• the logic 28 when the desired new sequence is very close to the previous sequence, it is obviously very easy to arrange the logic 28 so that it can retract the slow scrolling phase.
• the rough preselection could be done by removing a predetermined number at the desired address.
• the coarse preselection takes into account the maximum error which can occur from the fact that the counter is not following the values of marks actually present on the strip, but an estimate defined by the output of the sensor 20.
• the coarse preselection dependent on the value of the desired address, the dependency being recorded in a memory which can be direct access or even a read only memory.
• a sequence interrupt code will only stop playback.
• the present invention applies very particularly to the case of cassette tape recorders, of the 1/8 inch (3.175 mm) Philips Compact Cassette type, but it also more generally extends to any type of tape recorder player while scrolling. ment, whether it is a magnetic tape or any other type of tape serving as an information carrier.
• the invention also applies to the search for a sequence in video recorders, of the U-MATIC or VHS type in particular, by using their sound track or one of these, for example.

Landscapes

• Indexing, Searching, Synchronizing, And The Amount Of Synchronization Travel Of Record Carriers (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9221344

Family Applications (1)

Country Status (2)

Cited By (2)

Citations (2)

• 1979
  • 1979-01-30 FR FR7902294A patent/FR2448210A1/fr active Granted
• 1980
  • 1980-01-30 WO PCT/FR1980/000011 patent/WO1980001619A1/fr unknown

Patent Citations (2)

Also Published As

Similar Documents

Legal Events