DE2150807A1 - Method and arrangement for synchronizing the recording and playback speeds of a pair of transport devices each transporting a storage medium - Google Patents

Description

Patent attorneys Dipl.-Ing. F. We ic km an ν,

Dipl.-Ing. H.Weickmann, Dipl.-Phys. Dr. K. Fincke Dipl.-Ing. F. A. Weickmann, Dipl.-Chem. B. Huber

DXIII 8 MUNICH 86, DEN

PO Box 860 820

MÖHLSTRASSE 22, NUMBER 48 39 21/22

<983921/22>

Ampex Corporation, 401 Broadway, Redwood City, Calif. United States

Method and arrangement for synchronizing the recording and playback speeds of a pair of transport devices each transporting a storage medium

The present invention relates to a method and an arrangement for synchronizing the recording and playback speeds of a pair of transport devices each transporting a storage medium, storage location signals and pulse-shaped control signals being prerecorded on the storage media.

The method and the arrangement according to the invention are described below for the application in recording and reproducing devices with magnetic tapes. The invention is however, it is not restricted to such applications. Rather, the method according to the invention and the arrangement according to the invention can also be used, for example, for devices disc-shaped magnetic recording media are used. The method according to the invention and the

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Arrangement according to the invention can be used in connection with devices in which the information to be stored on the storage medium is processed in the form of information units or information segments, each segment being based on an addressing point recorded on or played back from the magnetic tape. An example of such "operation of devices" is Storage of visual information using video tape recorders manufactured by the applicant. In such devices it is necessary to have a printed document on two or more To store video tapes such as a main tape and a file tape. According to known methods, the document must first be at a predetermined location on the main tape recorded, after which the same Aufzeidi tion in one separate operation is to be carried out at a desired location on the video tape file. With a possible synchronization of a pair of Trare port devices, one of which the main tape and the other carrying the file tape so that these two recording operations are performed simultaneously It is very essential to save time to take care of both the device time and the working hours of operating personnel.

Corresponding advantages are associated with the playback of Segments of information from a plurality of tape storage locations, portions of the recorded information being stored on different tapes, each of which is in turn from a separate transport device. When rendering a set of associated information segments it is necessary to adjust the playback speed of one of the transport devices at a special overhead storage tunnel with the

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Playback speed of another transport device at the selected location of the tape associated with that device. This means that the information can be reproduced in a smooth, continuous process, i.e., the reproduction of the information appears as if it came from the same tape transport device. Such a process differs from previously known complex techniques in which the tapes on different Transport devices are preset to a predetermined location in the direction of movement in front of the addressing memory locations, and first one of the transport devices is syrchronized and the associated information segment is reproduced, after which the second transport device is synchronized to the one assigned to it To reproduce segment of information. The disadvantage of such a method is that between the end of the first reproduced information segment and the beginning of the next information segment there is a time delay which is due to the necessary transition in the synchronization of the first to the side transport device. To save time The resulting advantages are not only found in video signal storage devices. Rather, the same benefits are also given in cases where the signals are in digital form and in ilultibit words (or in a similar form) recorded at /. addressing points on the tape.

The present invention is therefore based on the object of an improved method and an improved arrangement for synchronization the recording and playback speeds of a pair of transport devices with respect to pre-marked ones

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Storage locations on the carried by the separate transport device Specify storage media.

This task is performed in a method of the type mentioned at the beginning according to the invention solved in that the transport devices for Playback of the storage locations signals are operated from the storage media,

that a predetermined one supplied by the first transport device Signal of the storage location signals and a predetermined signal of the storage location signals supplied by the second transport device is detected

that the given one delivered by the first transport device and sensed memory location signals to a reversible pulse counter to / change its counting position in one direction and the specified and supplied by the second transport device The recorded memory security signal is sent to the pulse counter to change the counting position in the other direction, and that the recording and playback speed of the trans-

ψ port devices is regulated as a function of the momentary counting position of the pulse counter, in such a way that the transport devices run at the same speed given a mean counting position of the ImpAs counter and if the counting position deviates from the central counting position on both sides as a function of the direction and size of the counting position in relation to the central counting position one of the transport devices is accelerated and the other is braked at the same time.

In a further embodiment of the invention is an arrangement for implementation of the method defined above by the following

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animal features marked:

separate signal detectors assigned to the transport devices for detecting a given memory location signal, of the signals reproduced by the transport devices, an up / down counter, which as a function of on a first input received pulses in Vorwürtsrichtung and as a function pulses received at a second input counts in reverse direction,

Gate, which is a delivered by the first transport device impuls Förrnicje's control signal as a function of the output signal of the associated detector to the first input of the counter and a pulse-shaped delivered by the second transport device iiegelsignal as a function of the output signal of the associated Coupling detector to the second input of the counter, and one coupled between the counter and the transport devices Digital-to-analog converter, which is based on the counting states of the Counter responds to a given counter position, to accelerate one transport device and the other transport device to decelerate, and responds to counting states of the counter on the other side of the predetermined counting position to the to brake one transport device and to accelerate the other transport device.

For example, when storing video images in a recording and reproducing device for documents in which certain Pages of the document on videotape and other pages of the same document can be stored on another video tape, according to the invention oine synchronization to the corresponding

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the transport devices carrying these tapes to the correct ones Tape addresses possible so that the pages of the document can be reproduced in a continuous uniform sequence. The synchronization of the two transport devices is done by measuring the relative locations of the selected tape storage locations in and through each transport device Acceleration of a transport device while at the same time the other transport device is braked until it hits the eye Get hold of the storage locations in synchronization. At this point, the acceleration and deceleration of the running speeds switched off and the speed of the phase of the transport devices synchronized with a common reference signal. The forward-backward pulse counter is used to monitor the relative displacement of the tape storage locations envisaged in s. When the counter is preset to the counter position, a circuit provided for this purpose detects the first preset Storage location signal generated by the respective tape transport devices After that, control track signals from the associated tape into one side of the forward-backward counter fed to initiate a count in one direction relative to the central count position, the default Memory location signal from the second transport device occurs, control track signals from the associated tape given to the other side of the up-down counter, so that a counteraction to the first transport device corresponding stored count occurs. Via digital-to-analog converter responds to the current counting position of the counter and supplies an analog speed control signal, its amplitude and polarity for simultaneous acceleration of a transport device and other decelerations

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the transport device is used in such a way that the two envisaged tape storage locations come in sync hronisation. When the amplitude of this analog speed control signal decreases, indicating that the counter is in its middle counting position approaches, the speeds of the corresponding tape transport devices come closer to the corresponding Normal or standard recording and playback speed. If the counter is in its middle counting position for a sufficiently long period of time, the speed control signals are activated switched ineffective by the digital-to-analog converter and the transport devices controlled by a standard reference signal, where the memory locations on the tapes are correct are synchronized.

A tape transport synchronization arrangement is already described in an earlier application by the applicant entitled "Fast image synchronization" of the signals reproduced from a video tape. In this arrangement the video image sequence from the tape koi,.:. Ide is synchronized with a reference image sequence by using a digital Pulse cooling of the control track pulses coming from the tape and a reference pulse train with appropriate periodicity is carried out. The stored digital count is converted into an analog signal to regulate the tape speed in the tape transport device special picture in which the signal coming from the tape is synchronized with the reference signal is not critical.

Further features and details of the invention result

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from the following description of an exemplary embodiment with reference to the single figure of the drawing. This figure shows a block diagram of the embodiment of the invention for Synchronization of a pair of record and playback transport devices at the given tape storage.

The arrangement according to the invention shown in the figure serves to synchronize the recording and playback speeds a pair of transport devices 1 and 2 at predetermined latch locations and prerecorded addresses, respectively on storage media which are transported by the transport devices.

In the present case, a magnetic tape (not shown) with a recording format runs on the transport devices 1 and 2, in which the information signals are contained in discrete groups or segments. For these information segments prerecorded and addressable memory location signals are provided. The transport devices can be used in a search mode operated to move the magnetic tape to an address suitable for recording or reproducing such a predetermined address Able to bring. In the present exemplary embodiment of the invention, the grouped information is transmitted by means of magnetic heads recorded which in a transverse direction to the tape movement

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running level / rotate, so that there are recording tracks lying transversely to the longitudinal direction of the tape. Each information segment can correspond, for example, to a single image of video information, in which case each memory location has an image pulse and an image that identifies the beginning of this special video image.

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fifying image address is assigned, regardless of whether whether this memory location has already been used or not. Furthermore, there is a longitudinal direction on the belt Control track provided, which carries a periodic pulse signal. This level track signal is used in a feedback mode, about the speed of the transport device on a stationary to maintain the specified value. Such a recording format is in a recording and reproducing apparatus realized for documents produced by the applicant will. However, the measures according to the invention also apply to other types of signal information and recording and reproducing devices applicable. In certain other devices, for example, the video information is replaced by digital information, which in a corresponding manner in segments or in grouping dits or words. Each such digital segment is stored in an address tape location. Even pre-recorded pulse-shaped signals are assigned to the digital segments, which mark the beginning of the segment in this way identify, as explained above using the image pulse to identify the beginning of each video image.

When the arrangement shown in the drawing is in synchronization mode operates for any given pair of images or locations, each one of which is a tape transport device 1 and 2, the pulse shape cone track information coming from the conveyor belts is used for recording the relative positions of the selected image areas. This is done by an up-down counter 11, which by an ochalt-

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and detector circuit 21 as well as one belonging to the transport device 2 Switching and Üetektorkreis 22 is controlled, each Apply control track pulses from the corresponding transport devices to various inputs of the counter 11. The counter 11 then assumes a counting position which indicates the phase difference between those on the corresponding bands existing selected memory locations; this fact is explained in more detail below.

The circle 21 contains an image selection stage 23 for acquiring a predetermined signal which is sent by the transport device 1 Image address signals picked up via a line 24. As a function the occurrence of the desired image address are an image pulse detector 26 and a preset input 27 of the counter Controlled via an output line 28 of the selection stage 23. Through this the counter 11 assumes a preset counting position which is preferably in the vicinity of the middle value of the counting range. In this case the counter, which has a counting range of 64 bits, is preset to a count of 31. Simultaneously the detector 20 responds to the next image pulse, whereby the beginning of that coming from the edge of the transport device 1 selected image is identified. The designated with FPl Image pulses are transmitted via a line 29 from the transport device placed on the detector 26. The combination of the image selection stage 23 and the pulse detector 26 is used to Detection of the beginning of the desired image on the belt of the transport device 1 / as a function of this detection process the detector 26 controls a gate 32 via an output line 31, as a result of which via a line 34 from the transport device

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Coming control track pulses labeled CT2 Via the gate 32 can be given to a forward input 33 of the counter 11. For the selected storage location or the image signal from the transport device 1 is therefore obtained by storing the control track pulses in the forward direction in the counter 11 starting from the preset mean counting position, a draw time »

The circle 22, which is composed of similar components, starts a count of control track pulses from this tape as a function of the occurrence of a selected memory location signal or image from the tape on the transport device. In this case, an image selection stage 36, which operates as a function of a selected image location, detects the occurrence of a suitable address from address signals supplied via a line 37 from the transport device 2 and, as a function thereof, controls an image pulse detector 3ό via a line first following image pulse delivered by the transport device via a line 41 detects. A decor gate 42 controlled by the detector 38 via a line 43 couples, as a function of the image pulse belonging to the selected image area, from the B _Q nd the transport direction 2 coming control track pulses to a reverse input 44 of the counter 11. These control track pulses run via an output line 4ό between the transport device 2 and a Entrance of gate 42.

The selected image or the selected storage location from the Transport device 1 therefore serves as a reference, the counter 11 from the pre-set central counting position in

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The forward direction counts until the desired memory location or the desired image address from the transport device 2 occurs. Then the control track pulses from the transport device 2 fed into the counter 11 at the input 44, so that the counting sequence with which the counter 11 functions as a function of the control track signals from the transport device 1 continues to count, decrease or * the counting direction is reversed. The moment counter of the counter 11 when the image pulse belonging to the transport device 2 occurs and following this image pulse therefore represents the phase or the position relation between the corresponding band image points.

For generating proportional speed control signals a digital-to-analog converter 51 serves as a function of the counting position of the counter, whereby the transport devices to the desired memory addresses are brought into synchronization. For this purpose, the converter 51 receives a large number of output bits 52 from the counter 11 and delivers them at an output 53 an analog control signal. This control signal has a size which is the phase or position difference between the selected Band addresses is proportional and the polarity, which is a hatred for the sense of direction, in which this phase difference occurs. In other words, the polarity is a hatred of whether the selected address belonging to the transport device 1 leading or lagging the selected address belonging to the transport device 2. The analog control signal produced at output 23 is via separate signal paths 58 and 59 to a Geschvi ndigkeitsregeleingang 56 or 57 of the transport device or 2 given. In one of these signal paths there is a polarity

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or! As long as the selected tape storage locations of the transport devices 1 and 2 are not yet synchronized, the transport speeds are controlled by the output signal of the converter 51 in the sense described. If the synchronization condition is met, the speed control inputs 56 and 57 are switched off from the output of the converter 51 and are coupled to standard reference speed control loops 61 and 62 for control. In order to be able to carry out this transition in the control process, circuits 63 and 64 are provided which are controlled by a synchronous detector 66 coupled to output 53 with an input 67. The detector 66 detects an output signal at the output 53 of the size zero and controls the circuits 63 and 64 as a function thereof.

Regarding the response of the transport devices 1 and 2 to the counting state of the counter 11, this counter is indicated in the above Meaning initially set in a middle counting position, which corresponds to counting 31 in the present case. The digital to analog converter 51 is designed so that it supplies an analog output signal at output 53, the size of which corresponds to the number of Counting positions is proportional by which the counting deviates from the mean counting with the l / ert 31. The polarity of the signal on Output 50 corresponds to the direction in which this count is related is offset to the middle number. Let us assume, for example, that the pulse count in the counter 11 initially as a function of a selected image pulse from the conveyor belt 1 and then as a function of a selected image impulse from the tape

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the transport device 2 takes place. For the interval between these pulses, the counter has 11 control track pulse intervals in the forward direction as a function of signals at the forward input 33 stored so that he can move a certain number of counting positions deviates from the middle counting position with the value 31 in the forward direction if the one belonging to the transport device 2 Image pulse occurs. In this case, the converter 51 supplies a control signal with a size which corresponds to the number of the

w [medium counting position corresponds to different counting positions and with a polarity which indicates that the desired tape storage location of the transport device 1 leads the selected tape storage location of the transport device 2. This analog control signal is passed through the circuit 58, which contains an inverter amplifier 71 for carrying out a polarity inversion, and a controlled gate 72 to the gate 56 of the transport device, whereby its transport speed is reduced by an amount proportional to the amplitude of the control signal. The speed control is carried out by

| a tape drive servo assembly 73 which is in the transport device 1 is included and drives the magnetic storage tape. In this way, the phase or location of the selected Storage location of the transport device 1 as a function of the output signal of the converter 51 delayed.

Simultaneously with the feeding of the control signal into the signal path 58, this signal is also fed into the signal path 59, but no polarity inversion takes place here. Signal path 59 includes an amplifier 76 (whose input and S * output are in phase) and a controlled gate 77 which

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selectively couples the amplifier 76 to the input 57 of the transport device 2. The size of the control signal in signal path 59 is the same as in signal path 50, but the signal polarities are opposite. A tape drive servo arrangement 58 in the transport device 2 responds to the signal at the input 57 and accelerates the tape movement by an amount proportional to this signal. In this way, the belt speed in the transport device 2 is increased by the same amount by which the belt speed in the transport device 1 is reduced.

Due to the differential acceleration and deceleration of the transport devices exceeds the repetition frequency of the control track pulses from the transport device 2, which is on the reverse input 44 of the counter 11 are given, soon the repetition frequency of the control track pulses from the transport device 1, which on the counter input 33 can be given. Therefore, the instantaneous counting position of the counter 11 is from its offset forward counting position back to the middle count position. As the counting position changes, the size of the converter / output signal increases at the signal output 53 towards zero, so that the differential acceleration and deceleration of the transport devices 1 and 2 is gradually reduced, whereby the tape speeds converge to the same standard recording and playback values.

It can happen that a rapid differential speed change in the transport devices leads to the belt speeds passing through the synchronization state.

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In this case, the transport device 2 then rushes ahead relative to the transport device 1. If this is the case, it works Counting position of the counter from the forward direction through the middle counting position to counting positions in the downward direction, so that the polarity of the speed control signal at output 63 goes through zero and assumes the other polarity. In order to a correct adjustment of the transport speeds takes place.

It is now assumed that the counter 11 gradually goes to its middle count position so that the tape speeds slowly come into a stable synchronized state. The synchronous detector 66 detects the zero condition of the output signal of the converter 51 at its input 67 and delivers a switching function signal as a function of this at a signal output 81. As a function of this state, the gates 72 and 77 are opened, so that the signal path between the amplifier 71 and the input 56 as well as the amplifier 76 and the input 57 is interrupted. Simultaneously therewith, gates 82 and 33 durciigeschaltet, so that now the ψ Geechwindigkeitsregeleingänge are connected to outputs 86 and 87 of Phasenverlgeichsstufen 88 and 89, 56 and 57th The pair of gates 72 and 82 are driven in opposite directions by a logic control inverter 91, which is connected to the circuit of the gate 82 (one gate is opened or closed, while the other is closed or opened). Correspondingly, a logic control inverter 92 is switched on in the circuit of gate 83, which controls gates 77 and 83 in opposite directions as a function of the switching signal at output 83.

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At outputs 86 and 87 of the phase comparison stages 88 and 89, control signals are generated as a function of a signal supplied by a reference signal generator 96 , with which the transport devices are regulated to a nominal speed and a nominal phase. Specifically, the generator 96 supplies a reference signal which is sent to one input of the comparison stages 88 and 89 and is compared there with the pulse-shaped control track signals CT1 and CT2 supplied by the corresponding transport devices. The output signals at the outputs 86 and u7 therefore regulate the sports devices 1 and 2 in such a way that the corresponding Dänder are driven at speeds at which the control track signals coming from them are adapted to the reference signal from the generator 96.

When the tapes are sent once to the desired pair of tape addresses are synchronized, they can still be operated synchronously with this particular band phase relationship. Is it desirable To synchronize other storage locations on the corresponding tapes, the operations described above are carried out repeated for the new addresses or image locations.

When using the arrangement according to the invention in the magnetic tape recorder with rotating scanning heads, for example in the devices The type of processing of video signals and certain digital signals mentioned above is the longitudinal speed of the tape not necessarily related to the transmission sequence of the information signal that is on magnetic transverse tracks or on below traces running at an angle to the longitudinal direction of the dand are recorded is. The function of such devices is as follows:

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BATH ORIGINAL

2) 50807

that the rotation of the transducer heads determines the signal transmission sequence during recording and playback, while the longitudinal speed of the dandes caused by the dandantrM) is only used for a correct phase adjustment of the bridge with respect to the rotating "andler, " because therefore the information signal in Segments or fields is recorded, the tape must be set in a correct position in the direction of movement in front of the desired image address and then with a standard dand

"speed driven so that the desired information signal corresponding magnetic tracks are in phase with the rotating heads. To achieve this becomes common recorded a signal on a longitudinal control track, which indicates the beginning of the information segment, the Band can be set correctly by monitoring only this longitudinal control track. That is the beginning of the addressed A signal indicating the memory location can be an image pulse which identifies the beginning of a video image. According to the invention the bands are therefore synchronized with speed

k driven which are related to the normal belt speed lead and lag so that certain information images or image locations are out of phase on the rotating head assembly be moved past. When the synchronization is reached, the desired Image addresses and when returning to a standard speed, the transverse information tracks arrive again with the rotating ones Magnetic heads in phase. This means that the signal information can be correctly recorded or reproduced on the selected one Tape storage location possible.

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Claims (7)

- 19 PATENT CLAIMS , 1 / Method for synchronizing the recording and playback speeds of a pair of transport devices each transporting a storage medium, wherein on the storage media storage location signals and pulse-shaped Control signals are prerecorded, thereby marked, that the transport devices are actuated to reproduce the storage location signals from the storage media, that a predetermined, supplied by the first transport device signal of the storage location signals and a predetermined, the signal of the storage location signals supplied by the second transport device is detected, that the predetermined and detected storage location signal supplied by the first transport device to a reversible Pulse counter for changing its counting position in a Direction and the predetermined and detected storage location signal supplied by the second transport device to change the counting position in the other direction is given to the pulse counter, and that the recording and playback speed of the transport devices as a function of the instantaneous Counting position of the pulse counter is regulated in such a way that the transport devices are in a central counting position of the pulse counter run at the same predetermined speeds and if the counting position deviates from the mean counting position on both sides as a function of the direction and size of the counting position in relation to the central counting position -20 209830/1080 one of the transport devices is accelerated and the other is "decelerated" at the same time. 2. The method according to claim 1, characterized in that the Occurrence of the middle count of the pulse counter is detected and as a function thereof the recording and playback speeds of the two transport devices with a reference timing signal be synchronized. 3. The method according to claim 1 and / or 2, characterized in that a digital output signal supplied by the pulse counter is converted into an analog control signal, the size and polarity of which corresponds to the number of counting positions and the direction, in which the eye position deviates from the line counting position, and that the recording and playback speeds the transport devices are controlled as a function of this control signal. 4. The method according to any one of claims 1 to 3, characterized in that the analog control signal via separate signal paths to one üervo input each for a speed control signal the transport device is given and that . the phase polarity of the analog control signal in one of the signal paths for controlling the speeds of the transport devices is inverted in opposite phase sense. 5. The method according to any one of claims 1 to 4, characterized in that for the operation of the two transport devices with the predetermined ι.υϊτΒ ichnungs- and Uicdergabegeschwindig- - 21 209830/1080 BATH ORIGINAL The reference timing signal is used and that as a function the detection of the mean counting position of the pulse counter the analog control signal to the servo inputs of the transport devices leading signal paths are interrupted and the reference clock signal is switched to the servo inputs will. 6.,. Regulation to carry out the procedure according to at least One of the preceding claims, characterized by separate signal detectors assigned to the transport devices (1/2) (26,28) for the acquisition of a given storage location signal, which is generated by the transport devices (1,2) reproduced signals, an up-down counter (ll), which as a function of pulses received at a first input (33) in the forward direction and as a function of at a second Input (44) received pulses in the reverse direction counts Gates (32, 42), which a pulse-shaped control signal supplied by the first transport device (1) as a function of the output signal of the associated detector (26) on the first input (33) of the counter (11) and a pulse-shaped crucible signal supplied by the second transport device (2) as a function of the output signal of the associated detector (30) on the second input (44) of the counter (ll) couple, and through one between the counter (11) and the transport devices (1,2) coupled digital-to-analog converter (15), which uuf counting states of the counter (ll) on one side of a 209830/1080 BATH ORIGINAL predetermined count position responds to a transport device to accelerate and to brake the other transport device and on counting states of the counter responds to the other Üeitedvorvoreg given counting position in order to brake the one transport device and the other Accelerate transport device. 7. Arrangement according to claim 6, characterized by a reference signal generator (9ό) for controlling the transport devices (1,2) to a predetermined speed, circuits (63, 64) for selective and alternating coupling of either the digital-to-analog converter (51) or the reference signal generator (96) to speed control inputs (56,57) of the transport devices (1, 2) and by a synchronous detector {66) which switches the circuits (63,64) into a switching state as a function of the predetermined counting position assumed by the counter (II), in which the reference signal generator (96) for regulating the transport devices (1,2) to the predetermined speed is coupled to them. S. Arrangement according to Claims 6 and 7, characterized by a polarity inverter (71) which is connected between the output of the digital-to-analog converter (15), which is the amplitude and polarity of the instantaneous counting part The analogue signal corresponding to the predetermined counting position of the counter (11) is sent to the transport devices (1, 2), so that a transport / ov "icUiuti-j bi: ·: - ^ fr.ouisicjencl and cue others; ΤΓαηε ^ 'ΓίνοΓΓίαΐίϊ ^ ί. ■■ '. -oinsend r ^! o'Lar iöL 209830 /, 080 ^ DO «. _Q , NAL