TAPE EDITING METHOD AND APPARATUS

Abstract: An improved tape recording apparatus is employed to record new information on a previously recorded tape (1) without creating a distorted or garbled recording at the leading portion of the newly recorded tape segment. In operation, tape transport controls (47) of the tape recorder are operated to move the tape (1) slowly over the playback head (5) in the play mode. The tape (1) is monitored and is stopped when a desired start-edit point is positioned over the playback head. An automatic edit control (57) then causes the tape (1) to move backward a particular distance without recording, so that the start-edit point shifts from the playback head (5) to the erase head (3). Thereafter the recorder head (5) of the player is deactivated, the erase head (3) is activated and the tape (1) is moved forward until the start-edit point is again positioned over the record head (5) and the tape segment between the record head and the erase head (3) is erased. The tape recorder is then activated to begin recording new information from the start-edit point.

Description: TAPE EDITING METHOD AND APPARATUS TECHNICAL FIELD The invention relates to tape recorders which are utilized to record information on a magnetic tape and to play back the information which is stored on the tape. More particularly, the invention relates to an. apparatus and method for adding newly recorded material to a previously recorded tape, so that the newly recorded material starts at a precisely determined position on the tape and is recorded in a manner that avoids playback distortion at the beginning of the added recording. BACKGROUND OF THE INVENTION It is well known that music or other audible sounds may be recorded and reproduced with high fidelity on magnetic tape recording machines. Such machines utilize an erase head and a spaced recording head to respectively erase and record audio signals on a moving magnetic tape. In the re¬ cording mode, a magnetic tape is initially moved over the erase head so that any previously recorded audio signals are erased and the tape is then moved over the record head to selectively induce in the tape a magnetic field that corres¬ ponds to the sound being recorded. In the playback mode the erase head is deactivated and the tape is moved over a play¬ back head which senses the magnetic field of the tape and generates a corresponding electrical signal which is applied to reproduce the recorded sound. The sensing or playback head may be the same head as was employed to record magnetic signals on the tape or may be an independently operable head that is positioned adjacent to the record head. In adding a new audio recording to a previously recorded tape, the tape is initially positioned so that a desired start-edit point of the old recording is over the record head. The new recording is then started at this point. When a magnetic tape is edited in the above- described fashion, a segment at the beginning of the new recording is garbled or distorted and therefore there is an annoying noisy transition between the old and new recordings. The undesirable distortion is caused by overlapping audio signals of the old and new recordings. This overlap is pro¬ duced due to the spacing of the erase head and record head of the tape recorder,- as is hereafter explained. As explained above, in editing a previously re¬ corded magnetic tape, a start-edit point on the tape is posi¬ tioned over the record head and the tape recorder is then activated to begin recording new audio signals from this point. As the tape moves forward, the erase head operates to erase the previously recorded material and the recording head operates to record the new material. However, the pre¬ viously recorded portion of tape which lies between the start-edit point and a point initially positioned over the erase head does not move over the erase head in the editing process and is therefore not erased. This segment of tape instead passes over the record head so that the segment has new audio signals recorded over the previously recorded audio signals. The playback of the combined signals produces a garbled or distorted sound. The above-described editing problem also occurs with video tape machines which record video signals and audio signals on a magnetic tape. The problem is recognized and solutions are suggested in H. Kybett, "Video Tape Recorders," pp. 216-221 (1975). In the Kybett publication it is suggested that distortion of an edited tape segment may be overcome by tem¬ porarily increasing the recording head current during the recording of the beginning of the segment and thereby strong¬ ly impressing the new recorded material over the previously recorded material. This recording scheme will not work for high fidelity recording systems which must record signals at near saturation levels on the tape. Increasing the record¬ ing current in such systems will merely push the tape into saturation and will therefore not provide useful audio sig¬ nals. Alternatively, it is suggested that an additional erase head placed adjacent to and immediately in front of the record head will erase the previously recorded material on the leading portion of the edited segment. The use of an additional erase head is undesirable because it adds expense and complexity to a recording system. It is therefore necessary to provide a relatively simple and inexpensive means for preventing signal distortion at the leading portion of an edited tape segment. Accordingly, it is an object of the invention to provide an apparatus and method for tape editing that is relatively simple and inexpensive and that insures that over¬ lapping signals will not be recorded at the leading portion of an edited segment of a magnetic tape. Another object of the invention is to provide such an apparatus and method which insures that the leading por¬ tion of a previously recorded tape segment is erased before it reaches the record head to record new audio signals. In editing magnetic tape it is necessary to pre¬ cisely position the desired start-edit point of the tape over the recording head. The start-edit point has heretofore been positioned in reel-to-reel tape recorders by rocking the take-up and supply reels back and forth over the playback head and monitoring the reproduced audio until the desired start point is positioned over the recording head. This manual system of positioning the tape is time consuming and clumsy. Also, this tape positioning system cannot be used for cassette tape recorders, because the reels of such re¬ corders are not accessible for manual manipulation. Accordingly, it is a further object of the inven¬ tion to provide a tape editing system wherein a desired start-edit point on a magnetic tape is precisely positioned without having to manually manipulate reels of tape. Another object of the invention is to provide such a system wherein positioning of the start-edit point is achieved by causing the tape transport apparatus of a re¬ corder to selectively move tape slowly over the playback head in the playback mode. A further object of the invention is to provide a tape editing apparatus with a tape transport mechanism that precisely positions a start-edit point of a tape over a re¬ cord head and an edit control mechanism which operates auto- matically to insure that the leading portion of an edited segment of the tape does not contain overlapping audio sig¬ nals. SUMMARY OF THE INVENTION In order to achieve the objects of the invention and to overcome the problems of the prior art, the tape edit¬ ing method and apparatus of the invention includes a mech¬ anism for selectively moving the magnetic tape of a tape recorder in a reverse or forward direction with respect to a playback head. The speed of movement is sufficiently slow to allow monitoring of the tape and precise stopping of the tape at a desired start-edit point. An edit control mechanism is provided to insure that the tape segment between the erase head and the start- edit point is erased before edit recording of the tape is started. In operation, the desired start-edit point of the tape is initially positioned over the playback head. There¬ after, an edit function switch is selected to initiate an automatic erase sequence for the edit. The erase sequence starts when a pinch roller presses the magnetic tape of the recorder against a rotating capstan which then moves the tape backward. When the pinch roller engages the tape and capstan a counter is reset to zero and thereafter begins counting the rotations of the capstan to a predefined count state which is reached when the backwardly moving start-edit point reaches the erase head. When the predefined count is reached, the control circuit disengages the pinch roller and stops the backward movement of the tape so that the start-edit point is posi¬ tioned over the erase head. Thereafter, the direction of rotation of the capstan is reversed and the pinch roller is again engaged with the tape and capstan to move the tape forward. When the pinch roller engages the capstan the coun¬ ter is again reset to zero and begins counting the rotations of the capstan to a predetermined count state which is reached by the counter when the start-edit point of the tape moves forward from the erase head to the record head. As " the tape moves forward the erase head is activated and the record head is deactivated. When the counter indicates that the start-edit point of the tape has reached the record head, the pinch roller is disengaged and the forward movement of the tape is stopped. At this point the tape between the record head and the erase head has been erased. The recording function is thereafter initiated to record new audio signals on the tape. BRIEF DESCRIPTION OF THE DRAWINGS FIGURES 1A-1B show a diagrammatic perspective view of the relation between a previously recorded magnetic tape, erase head and record/playback head in a prior tape editing system. FIGURES 2A-2C show a diagrammatic perspective view of the relation between a previously recorded magnetic tape, record/playback head and erase head in the tape editing sys¬ tem of the invention. FIGURES 3A-3D show a diagrammatic perspective view of the relation between a previously recorded magnetic tape, record head, playback head and erase head in the tape editing system of the invention. FIGURE 4 shows a diagrammatic illustration of a tape recording apparatus which provides the editing features of the invention. FIGURE 5 is a perspective view of a mechanism for monitoring the rotation of the capstan of the tape recording apparatus of FIG. 4. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The remaining portion of the specification describes preferred embodiments of the invention when it is read in conjunction with the attached drawings, in which like refer¬ ence characters designate identical apparatus. FIGS. 1A and IB show a perspective view of a mag¬ netic tape 1 of a prior art tape recorder in relation to an erase head 3 and a record/playback head 5 of the recorder. FIGS. 1A and IB are not drawn to scale and are provided mere¬ ly to show the relative longitudinal orientation of the heads 3 and 5.and associated tape 1 in a prior art tape editing system. The cross-hatched lines of the tape 1 indicate that the tape has audio information recorded on its illustrated segment. In FIG. 1A, the tape is positioned to record new audio signals, beginning at a start-edit point Tl. When Tl is positioned over the record/playback head 5 as shown, the point T2 of the tape is positioned over the erase head 3. FIG. IB illustrates the condition of the tape 1 after it has been moved forward a distance in the direction of the arrow 7 to record new audio signals from the start- edit point Tl. In operation, the tape is moved forward in a manner known to the art and the head 5 is operated to record OMPI | τ ..ι?o the desired audio signals on the tape, while the erase head 3 is operated to erase the tape. The new audio signals are indicated by cross hatching which is angled differently than the cross hatching of the previously recorded material of FIG. 1A. As shown in FIG. IB, the new audio signals are recorded over the old audio signals on the segment of tape between the points Tl and T2 and therefore, when the tape is rewound and played, the portion of the tape between Tl and T2 will produce a distorted sound. The tape after the point T2 has a proper new recorded signal because the erase head 3 operated to erase this section of the tape before it reached the recording head 5. FIGS. 2A, 2B and 2C illustrate the tape editing method of the invention. In operation, the tape 1 is ini¬ tially positioned for editing as shown in FIG. 1A. There¬ after an automatic editing sequence is initiated to provide the tape movement illustrated in FIGS. 2A-2C. As shown in FIG. 2A, the start-edit point Tl of the tape 1 is initially automatically moved in the direction of the arrow 9 from the record/playback head 5 to the erase head 3, at which point the tape is stopped. Thereafter, as shown in FIG. 2B, the " erase head 3 is activated, the record/playback head 5 is de¬ activated and the tape 1 is moved forward in the direction of an arrow 7 until the start-edit point Tl is again over the record/playback head 5. When the point Tl is stopped over the record/play¬ back head 5, the tape between the points Tl and T2 has been erased by the operation of the erase head 3. Thereafter, as shown in FIG. 2C, the tape 1 is moved forward to record new audio signals, with the head 5 acting as a record head and the erase head 3 erasing the tape in the usual manner. Thus, there is no signal distortion between the points Tl and T2 and there is therefore a clean and smooth transition between the previously recorded segment 13 and the new recorded seg¬ ment 15. FIGS. 3A, 3B, 3C and 3D illustrate the operation of the editing system of the invention with a recording mech¬ anism that utilizes an erase head 3 and a separate record head 17 and playback head 19. FIG. 3A illustrates the posi- tioning of the previously recorded tape 1 in relation to the heads 3, 17 and 19 when the tape is set to begin adding an edited segment at the start-edit point Tl. The start-edit point Tl is positioned over the play head 19 and according to the convention established above, the point over the erase head 3 is designated T2. When the automatic editing sequence is initiated the tape is moved backward in the direction of the arrow 9 until the start-edit point Tl is positioned over the erase head 3. Thereafter, as shown in FIG. 3C, the tape is moved forward with the erase head operating and the record and play heads deactivated. The forward movement of the tape is stopped when the start-edit point Tl is opposite the record head 17. At this point the erase head 3. has erased the seg- - ment of tape between the point Tl and a point T3. The tape is thereafter started to begin recording the new edited segment with the erase head 3 operating to erase tape and the record head 17 operating to record audio signals on the tape. As shown in FIG. 3D, there is no dis¬ tortion between the points Tl and T2 of the tape. The editing system illustrated in FIGS. 2A-2C and FIGS. 3A-3D may be implemented by a tape recording apparatus illustrated in diagrammatic form in FIG. 4. It should gener¬ ally be understood that FIG. 4 is illustrative of an embodi¬ ment of a tape recorder that will provide the desirable edit- ing features of the invention, but is not the sole means by which the functions of the invention may be achieved. As will be apparent to those skilled in the art, the invention may be embodied in other apparatus known in the art. The apparatus of FIG. 4 is therefore illustrative and not limit- ing. In the tape recording apparatus of FIG. 4, magnetic tape 1 is moved from a supply reel 21 to a take-up reel 23 in either the recording or playback operation of the appara¬ tus. An erase head 3 and a record/playback head 5 operate to respectively erase and record or play in a manner known to the art. A capstan 25 is rotated by a capstan motor 27 -5 to precisely move the tape between the supply reel 21 and take-up reel 23. In addition, a supply reel motor 29 and take-up reel motor 31 operate to turn their respective reels and thereby provide the tension required to move the tape smoothly over the erase head 3 and record/playback head 5. 0 The capstan 25 engages and thereby moves the tape 1 when a pinch roller 33 presses the tape against the capstan 25. The pinch roller 33 is engaged and disengaged from the capstan under the control of a pinch roller solenoid 35. Thus, the operative state of the solenoid 35 determines 5 whether or not the capstan will move the tape 1. The capstan motor 27 can rotate the capstan 25 to move the tape 1 in the forward direction of the arrow 7 or the reverse direction of the arrow 9. More particularly, the motor 27 will turn the capstan in a counterclockwise 0 direction with respect to the drawing of FIG. 4 to move the tape in the forv/ard direction of the arrow 7 and will rotate the capstan in the clockwise direction to move the tape iri the reverse direction indicated by the arrow 9. A capstan transducer 41 generates either one elec- 5 trical signal or a fixed number of signals for each rotation of the capstan. The signals from the transducer 41 are applied through a tape transport control 47 to a counter 43 which counts the number of signals and hence the number of rotations of the capstan. 0 A brake mechanism 45 such as is known in the art is provided to quickly stop the supply and take-up reels 21 and 23 when the pinch roller 33 is disengaged from the cap¬ stan 25. The tape transport control mechanism 47 is pro- 5 vided to control the operation of the take-up and supply reel motors, the direction of rotation and speed of the cap¬ stan motor 27, the actuation of the solenoid 35 and brake mechanism 45 and the activation of the erase head 3 and record/playback head 5. The tape transport control 47 operates in accordance with instructions that are received from button-actuated control select switches including a stop switch 48, record switch 49, play switch 51, rewind switch 53, fast forward switch 55, edit enable switch 57 and precision edit switch 59. The tape ' transport control 47 may include a micro¬ processor and a suitable interface circuit for receiving status signals from the various components of the system and generating control signals to operate the components. Such a microprocessor could, for example, include the counter 43 and a memory device for storing the required count state of the counter and the program steps for the above-described automatic edit sequence. The microprocessor could utilize a quartz clock to provide the necessary timing signals for the system. In operation, simultaneous pressing of the record and play switches 49 and 51 will cause the tape 1 to be moved in the forward direction 7 for normal recording of audio signals. In such normal operation the tape is erased as it moves over the activated erase head 3 and the record/playback head 5 is operated to selectively magnetize the tape to re¬ cord audio signals. The tape is moved forward in the normal record mode when the tape transport control 47 energizes the sole¬ noid 35 and thereby causes the pinch roller 33 to press the tape 1 against the capstan 25. The tape transport control 47 operates the motor 27 to rotate the capstan at a desired recording speed in the counterclockwise direction and oper¬ ates the motors 29 and 31 to control the unwinding and wind¬ ing of tape on the reels 21 and 23. The above-described recording operation of the apparatus of FIG. 4 is stopped by pressing the stop switch 48. The activation of the stop switch 48 causes the tape transport control 47 to deenergize the solenoid 35 and there¬ by disengage the pinch roller 33 and capstan 25. The take-up OMPI and supply reel motors 29 and 31 are also deenergized and, when the pinch roller 33 is disengaged, the brake mechanism 45 is actuated to stop the supply and take-up reels. When the apparatus of FIG. 4 is stopped, the rewind switch 53 may be selected to instruct the tape transport control 47 to operate the motors 29»and 31 in a manner known to the art to quickly wind tape from the take-up reel 23 to the supply reel 21. Likewise, the fast forward switch may be pressed to cause the tape transport control 47 to operate the- reel motors 29 and 31 to quickly wind tape from the supply reel to the take-up reel. The edit enable switch 57 is pressed when it is desired to precisely position a start-edit point of the tape 1 adjacent to the record/playback head 5 and to provide an automatic sequence of controlled tape movements which prepare a tape for editing. The edit mode and any associated editing operations can be terminated at any time during an edit se¬ quence by pressing the edit enable switch 57 an additional time. When the edit mode is terminated the tape will stop and the control 47 will return the recorder to normal record¬ ing and playback operation. In operation, the edit enable switch is pressed -to define a tape edit mode for the tape transport control 47. Thereafter either the rewind switch 53 or fast forward switch 55 may be actuated to move the tape at a relatively slow speed in a selected direction. More particularly, in the edit mode the tape transport control 47 energizes the sole¬ noid 35, which causes the pinch roller to engage the rotating capstan 25 and thereby moves the tape 1 at a predefined speed and in a direction determined by the actuation of either the rewind or fast forward switch. For as long as the fast for¬ ward switch is pressed, the tape is moved in a forward direc¬ tion slowly over the head 5 and the audio signals produced by the head 5 are monitored by speakers (not shown). Thus, an operator can monitor the contents of the slowly moving tape and thereby readily identify the start-edit point at which he wishes to insert new audio material. When the operator monitors the start-edit point, he releases the fast forward switch 55 to stop the tape and to thereby place the tape in the position shown at FIG. 1A. If the tape moves forward beyond the start-edit point, the rewind switch is pressed to cause the tape to slowly move backward for as long as the switch is pressed. It should be appreciated that the above-described start-edit positioning system will enable an operator of a cassette recorder to precisely define the starting point for an edited segment of tape. This edit positioning system also has application for reel-to-reel recorders which have heretofore been set at edit positions by manually manipulat¬ ing relatively bulky reels. The above-described system for defining a start- edit position utilizes relatively slow moving capstan and reel motors to provide the required continuous slow tape movement for as long as either of the switches 53 or 55 are pressed in the edit enable mode. A different mode of operation may be provided by modifying the control 47 to move the tape at a relatively slow speed, for example one half of normal playback speed, when the fast forward switch 55 is initially pressed in the edit enable mode. If the switch remains pressed, the control 47 automatically increases the speed of movement of the tape to a predefined maximum, for example two times normal play¬ back speed. The rewind switch 54 operates in a similar fashion in the edit enable mode to initially move the tape backward at a predefined slow speed which is automatically increased to a predefined maximum speed while the switch 53 is pressed. In such a modified system a tape is quickly scanned to determine a rough position for the start-edit point and thereafter the rewind and fast forward switches are operated to move the tape back and forth within the area of interest. When the start-edit point of the tape 1 has been precisely located over the record head 5 the depressed fast forward or rewind switch is released to stop the tape in the OMPI • 'Λft. IΪO position indicated at FIG. 1A. Thereafter, the precision edit switch 59 is pressed to initiate the following sequence of automatic tape-editing operations. As shown in FIG. 2A, when the switch 59 is pressed in the edit enable mode the tape transport control 47 initially operates the capstan motor 27 to rotate the capstan 25 to a predetermined speed in the clockwise direction and then engages the pinch roller 33 with the capstan 25 to move the tape 1 in the reverse direction indicated by the arrow 9. When the pinch roller 33 engages the capstan 25, the microswitch 61 is operated to signal the engagement to the tape transport control 47. The tape transport control 47 then resets the counter 43 to an initial count state, for example a zero count state. The capstan transducer 41 gener- ates a predetermined number of signals for each rotation of the capstan 25 and these signals are applied to increment the counter 43. The counter 43 counts the signals from the capstan transducer 41 and generates a tape stop output signal when a predetermined number of counts is reached. The pre- determined number of counts corresponds to the distance be¬ tween the record/playback head 5 and erase head 3. Thus, the counter 43 generates a tape stop output signal when the start-edit point Tl of FIG. 2A is positioned over the erase head 3. The stop-tape signal from the counter 43 is applied to the tape transport control 47 which then disengages the pinch roller 33 from the capstan 25, stops the reel motors 29 and 31 and actuates the brake mechanism 45 to stop the reels 21 and 23. Thus, the start-edit point Tl of the tape 1 is at the position shown in FIG. 2A. The tape transport control 47 thereafter reverses the direction of rotation of the capstan 25 so that the cap¬ stan rotates at a predetermined speed in the counterclockwise direction with respect to FIG. 4. The solenoid 35 is then energized again so that the pinch roller 33 engages the cap¬ stan 25 and the microswitch 61 signals the engagement. The control 47 resets the counter 43 ' when it receives the pinch roller engagement signal from the microswitch 61. Thereafter the capstan transducer 41 generates signals which are coun¬ ted by the counter 43 as the tape 1 moves in the forward direction of the arrow 7. As the tape moves forward, the tape transport control 47 also deactivates the record/play¬ back head 5 and activates or energizes the erase head 3. Thus, the tape that passes over the erase head 3 is erased as it moves in the forward direction and the tape that passes over the record/playback head 5 is unaffected. When the start-edit point Tl of the tape 1 is over the record/playback head 5 the counter 43 reaches its pre¬ determined count state and generates a tape stop output sig¬ nal to the control 47 to indicate the end of the automatic edit sequence. The tape transport control 47 therefore dis- engages the pinch roller 33, stops the capstan motor 27 and take up reel motors 29 and 31 and actuates the brake mechan¬ ism 45 to stop the tape in the position shown in FIG. 2B. The control 47 then automatically returns the recorder to its normal operational mode. As explained above, the edit enable switch may be pressed to terminate the edit sequence at any time before the automatic end of edit point is reached. As shown in FIG. 2B, after the edit sequence is - completed, the portion of tape between the points Tl and T2 has been erased by the erase head 3 and the prerecorded por- tion of the tape in front of the point Tl has not been affected, because the record/playback head 5 was not acti¬ vated. The tape recording apparatus of FIG. 4 will remain in its disengaged and stopped position until the record and play buttons are simultaneously pressed to start recording the new edited material on the tape. As explained with re¬ spect to FIG. 2C, the edited material will be provided on the tape following the point Tl and there will be no signal distortion between the points Tl and T2. The mechanism of FIG. 4 has been described with respect to an erase head and a single additional head that incorporates both the record and playback functions. It should be understood that the mechanism could be easily modi¬ fied to operate with an erase head and separate record and playback heads. In this case the system would operate to move the tape in the manner described with respect to FIGS. 3A-3D. As illustrated in those figures, the counter 43 would count to a first count state to move the start-edit point Tl backward from the playback head 19 to the erase head and would count to a second count state to move the point Tl from the erase head to the record head 17. Thus, if separate record and playback heads are used, the apparatus of FIG. 4 would necessarily be modified so that the counter 43 would generate a tape stop Output signal at the first count state when the tape is moving in the reverse direction and at the second count state when the tape is moving in the forward direction. This change in operation could be easily implemented for the tape transport control of FIG. 4. FIG. 5 illustrates a perspective view of a capstan transducer mechanism that could be employed to generate sig- nals corresponding to the rotation of the capstan. As shown in FIG. 5, the capstan 25 is supported on a capstan flywheel 63 which is rotated by the capstan motor 27. A light-emitting diode 65 is supported over the flywheel 63 and directs a continuous beam of light adjacent to but spaced from the outer periphery of the flywheel. The beam of light is re¬ ceived by a phototransistor 67 which is disposed opposite the LED. An opaque tab 69 is affixed to the outer rim of the flywheel 63, for example by an adhesive, to periodically interrupt the beam of light from the LED 65 to the photo- transistor 67 as the flywheel rotates. The interruptions in the beam thereby provide an indication of the rotation of the flywheel. In the embodiment of FIG. 5 a single tab is pro¬ vided to interrupt the beam once for each rotation of the flywheel. However, it should generally be appreciated that any number of tabs can be employed to provide any predeter¬ mined number of interruptions of the beam for each rotation of the flywheel. The phototransistor 67 generates a signal for each interruption of the beam in a manner well-known to the art and applies the signal to the input of- the counter 43 through the tape transport control 47. As explained above, the coun¬ ter counts the signals from the phototransistor 67 and gener¬ ates an output signal when a predetermined count state is reached. It should be understood that the optical trans¬ ducer of FIG. 5 may be constructed in many different ways. For example, one or more passages could be drilled through the flywheel 63 to intermittently pass the light of the LED 65 to the phototransistor 67. Alternatively, the flywheel 63 could be painted black and reflecting strips could be adhered at the periphery of the flywheel to intermittently reflect the beam of light from the LED to a phototransistor posi¬ tioned on the same side of the flywheel as the LED. It will be appreciated by those skilled in the art that other types of transducers could be used without depart¬ ing from the invention. For example, one or more magnets- could be mounted at the periphery of the flywheel 63 and a coil could be positioned in spaced relation to the flywheel to detect the fields of the rotating magnets. Alternatively, the flywheel could periodically actuate a mechanical switch and thereby provide the required electrical signal indicative of the number of rotations. The apparatus of FIG. 4 was described with respect to the operation of a single capstan 25 that is rotated in opposite directions to change the direction of movement of the tape 1. It should be understood that the invention is not limited to such a single capstan system. Thus, the ap¬ paratus of the invention could include two or more capstans operating to move the tape in desired directions. In such a system the capstans would rotate in a manner known to the art to define opposite directions of movement of the tape. For example, the capstan.25 illustrated in FIG. 3 would rotate in a known manner in association with an addi¬ tional capstan to move the tape in the forward direction of the arrow 7. In such a system the tape transport control 47 would operate the capstan motors to provide a desired speed and direction of tape motion for the above-described opera¬ tional modes of the recorder. The invention has been particularly described with respect to an audio tape recording system. However, the invention may also be used to advantage in video tape systems to avoid recording undesirable overlapping signals at a lead¬ ing portion of an edited segment of video tape. The inven¬ tion is therefore not limited to audio applications and may be embodied in many other forms without departing from its spirit or essential characteristics. The present described embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the in¬ vention being indicated by the claims rather than by the foregoing description. All changes which come within the meaning and range of the equivalents of the claims are there¬ fore intended to be embraced therein. _OM?

Claims: CLAIMS : 1. A tape recording apparatus for editing a previous¬ ly recorded tape, comprising: access means for recording information on said tape and for sensing the recorded information; erase means spaced with respect to said access means for erasing information from said tape; means for positioning a desired start-edit point of said tape adjacent to said access means; edit means responsive to an edit command for moving the tape so that the start-edit point is initially shifted from its position adjacent the access means to a position adjacent to the erase means and thereafter moving the tape so that the start-edit point is shifted from the erase means back to a position adjacent to the access means; means for activating the erase means and deactivat¬ ing the access means while the tape is moved to shift the start-edit point from the erase means to the access means, so that tape moving over the erase means is erased and tape moving over the access means is unaffected; and means for activating the erase means and access . means to record information on the tape after the start-edit point is shifted from the erase means and is adjacent to the access means. 2. The apparatus of claim 1, wherein said access means includes a magnetic head and means for operating the head to record information on the tape or sense recorded information on the tape. 3. The apparatus of claim 1, wherein said access means includes a record head for recording information on the tape and a separate playback head for sensing recorded information on the tape. 4. The apparatus of claim 1 wherein said erase means includes an erase head for erasing information from adjacent moving tape. 5. The apparatus of claim 1, wherein said means for positioning includes means for selectively moving tape over said access means in a forward or a reverse direction at a speed sufficient to allow audio monitoring of the tape and to allow the tape to be stopped when a desired start-edit point of the tape is adjacent to the access means. 6. The apparatus of claim 5, wherein said means for selectively moving includes means for moving tape in a selected direction initially at a first predetermined speed and thereafter increasing the speed of movement to a second predetermined greater speed. 7. The apparatus of claim 1, wherein said edit means includes, at least one capstan for rotating to move said tape in a selected direction; a counting means for counting the number of rota . - tions of said at least one capstan; and control means for operating the capstan to move the tape predetermined forward and reverse distances defined by the count state of said counter. 8. The apparatus of claim 7, wherein said counting means includes a capstan transducer for generating a fixed number of electrical signals for each rotation of said cap¬ stan and a counter for counting the signals from a predefined reset state to a count state corresponding to the distance between said access means and said erase means. 9. An information storage and retrieval apparatus comprising: a medium for recording information; erase means for erasing selected portions of infor¬ mation recorded on said medium,- access means in spaced relation to said erase means for recording information on selected portions of the medium ;5 and sensing recorded information on the medium; means for moving the recording medium in relation to said access means and said erase means to position a de¬ sired start-edit point on the medium adjacent to said access means; and 0 edit means for moving the medium with the erase means and access means deactivated so that the start-edit point is initially shifted from its position adjacent the access means to a position adjacent to the erase means and thereafter moving the medium with the erase means activated 5 and access means deactivated until the start-edit point is shifted from the erase means to a position adjacent to the access means. 10. The tape recording apparatus of claim 9, wherein said medium is a magnetic tape. 0 11. A tape recording apparatus comprising: a magnetic tape for recording audio signals; an erase head for erasing audio signals of the magnetic tape; a record/playback head for recording audio signals 5 on the tape and sensing signals for audio playback, the record/playback head being spaced from the erase head; transport means for selectively moving the tape forward over the erase and record/playback heads to erase, record and sense the audio signals of the tape and for re- 0 winding the tape in a reverse direction opposite the forward direction of movement; and editing means for automatically rewinding the tape to move a selected start-edit point of the tape from the record/playback head to the erase head and for automatically _OMPI _ VvL-O : lO moving the tape forward thereafter with the erase head acti¬ vated and the record/playback head deactivated until the start-edit point is positioned opposite the record/playback head. 12. The tape recording apparatus of claim 11, further including means for positioning said desired start-edit point of the tape adjacent to the record/ playback head, the means for positioning including means for selectively moving the tape over the record/playback head in the forward or reverse direction at a speed sufficient to allow audio monitoring of ' the tape and to allow the tape to be stopped when the desired start-edit point of the tape is adjacent to the record/play¬ back head. 13. A tape recording apparatus comprising: a magnetic tape for recording audio signals; an erase head for erasing audio signals of the magnetic tape; a record head for recording audio signals on the tape and a playback head adjacent to the record head for sensing the signals for audio playback, the record head and playback head being spaced from the erase head; transport means for selectively moving the tape forward over the erase, record and playback heads to respec¬ tively erase, record and sense the audio signals of the tape and for rewinding the tape in a reverse direction opposite the forward direction of movement; and editing means for automatically rewinding the tape to move a selected start-edit point of the tape from the playback head to the erase head and for automatically moving the tape forward thereafter with the erase head activated and the record head deactivated until the start-edit point is positioned opposite the record head. 14. The tape recording apparatus of claim 13, further including means for positioning said desired start-edit point of the tape adjacent to the playback head, the means for positioning including means for selectively moving the tape over the playback head in the forward or reverse direction at a speed sufficient to allow audio monitoring of the tape and to allow the tape to be stopped when the desired start- edit point of the tape is adjacent to the playback head. 15. A method for editing information recorded on mag¬ netic tape of a tape recording and playing machine having a record/playback head for recording and sensing information on a forwardly moving tape and a spaced erase head positioned behind the record/playback head for erasing information pre¬ viously recorded on the tape, the steps comprising: positioning a predetermined start-edit point of a previously recorded tape opposite the record/playback head; moving the tape backward a particular distance without recording or erasing until said start-edit point is positioned opposite the erase head; deactivating said record/playback head and activat¬ ing said erase head; moving the tape forward said particular distance, so that the erase head erases the tape over said particular distance and the record/playback head does not record over the particular distance; and moving the tape forward while operating the re- cord/playback head to record new information and the erase head to erase associated portions of the tape. 16. A method for editing information recorded on mag¬ netic tape of a tape recording and playing machine having a record head for recording and a playback head for sensing information on a forwardly moving tape and a spaced erase head positioned behind the record and playback heads for erasing information previously recorded on the tape, the steps comprising: positioning a predetermined start-edit point of a previously recorded tape opposite the playback head; moving the tape backward a first particular dis¬ tance without recording or erasing until said start-edit point is positioned opposite the erase head; deactivating said record and playback heads and activating said erase head; moving the tape forward a second particular dis¬ tance to said record head, so that the erase head erases the tape over the second particular distance and the record head does not record over the distance; and moving the tape forward while operating the record head to record new information and the erase head to erase associated portions of the tape.

Inventors: MILLS FREDERICK L III, MILLS, FREDERICK, L., III
Applicants: MILLS FREDERICK L III, MILLS, FREDERICK, L., III
Application year: 1983
Main classification: G11B27
IPC codes: G11B27