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This invention relates generally to magnetic recording and reproducing
systems, and more particularly is directed to systems by which documents,
pictures or other visual information and corresponding sounds or oral
explanations can be recorded, and ready access may be had to any selected
document, picture or visual information and the corresponding sounds or
oral explanations for virtually instantaneous reproduction thereof.
It is now well known to utilize a magnetic recording and reproducing system
to record and reproduce motion pictures or television video signals, such
a system being commonly referred to as a video tape recorder. In video
tape recorders, the television signals are recorded and reproduced or
displayed in a specified order and time relationship corresponding to the
order and time relationship of the respective frames. It has also been
proposed to employ a similar system for recording and selectively
reproducing or displaying various bits or pieces of information, such as
the contents of books, photographs, graphs, tables or other documents
convertible into corresponding data or document signals in the form of
video signals which are recorded on a magnetic tape and thereafter
reproduced therefrom. It will be apparent that each recorded data or
document signal bears no specified time relationship to any other document
signal, so that the retrieval of any selected bit or piece of recorded
information requires that each such bit or piece of information be
recorded in association with a particular index signal by which it can be
located and identified when its reproduction or display is desired.
In my copending U.S. patent applications Ser. No. 591,596, filed Nov. 2,
1966, and Ser. No. 691,787, filed Dec. 19, 1967, I have disclosed data
retrieval systems of the type described above in which the index or
identification signals are all the same and the locations along a magnetic
tape at which the various bits or pieces of information are recorded are
identified and selected by counting the numbers of such index signals from
one end or the other of the tape to the location of the selected document
signal. In such previously disclosed data retrieval systems, only visual
information, such as the contents of books, photographs, graphs, tables,
or other documents, can be recorded and selectively reproduced, whereby
the possible applications of such systems are limited.
Accordingly, it is an object of this invention to provide a system by which
documents, pictures or other visual information and also corresponding
sounds or oral explanations can be recorded, and ready access may be had
to any selected document, picture or visual information and the
corresponding sounds or oral explanations for virtually instantaneous
reproduction thereof.
In accordance with an aspect of this invention, a system for recording and
reproducing both still pictures or other visual information and sounds
related to such pictures employs a magnetic tape having index signals at
intervals therealong to identify respective portions of the tape which is
moved in a predetermined path to bring a selected tape portion to a
recording and reproducing station at which video signals and audio signal
magnetic heads are moved at relatively high and low speeds, respectively,
across the path, for example, by being rotated in spaced parallel planes
extending obliquely with respect to the path of the tape, for scanning
respective stripe-like areas on the selected tape portion, and the heads
are operated during the movement thereof to selectively record and
reproduce video and audio signals in the respective stripe-like areas
being scanned thereby. By reason of the relatively low speed at which the
audio signal magnetic head or heads move during scanning of the respective
stripe-like area or areas of a selected tape portion, such stripe-like
area or areas may have recorded therein audio signals corresponding to
sounds of substantial duration, for example, a duration of 20 seconds, so
as to be sufficient for an oral explanation, description or the like
corresponding to the still picture, document or other visual information
represented by the video signal recorded in the stripe-like area or areas
of the same tape portion.
A system according to this invention, by reason of its capability of
recording visual information and corresponding sounds and of affording
ready access to any selected recorded visual information and the
corresponding sounds for virtually instantaneous reproduction thereof, is
suitable for advertising, education or information purposes, as will be
apparent.
The above, and other objects, features and advantages of the invention,
will be apparent in the following detailed description of illustrative
embodiments thereof which is to be read in connection with the
accompanying drawings, wherein:
FIG. 1 is a schematic view of a length of magnetic tape having video, audio
and index signals recorded thereon in accordance with this invention;
FIG. 2 is a schematic elevational view of a magnetic recording and
reproducing unit according to this invention;
FIG. 3 is a schematic sectional view taken along the line III--III on FIG.
2;
FIG. 4 is a schematic and block diagram illustrating the major components
of a magnetic recording and reproducing system according to this
invention; and
FIG. 5 is a further schematic and block diagram illustrating additional
components of the system.
Referring to the drawings in detail and initially to FIGS. 4 and 5 thereof,
it will be seen that a magnetic recording and reproducing system according
to this invention, as there shown, comprises an image pickup unit or
television camera 10 for picking up the image of a document D, such as the
page of a book, a photograph, graph, table or other visual information to
be recorded, and for converting the image of document D into a
corresponding video signal which is transmitted through a modulator 11 for
angular modulation by the latter. The angularly modulated video signal is
transmitted to a video signal storing device 12 where the video signal is
recorded and can be reproduced repeatedly for any desired duration. For
example, the video signal storing device 12 may include a magnetic disk or
sheet 12a which is suitably rotated to effect a single revolution in the
time required for a video signal corresponding to the image of document D,
whereby the video signal corresponding to the document will be recorded,
as by a recording and reproducing head 12b in an annular track on disk
12a. The video signal stored in device 12 and reproduced by head 12b
thereof may be transmitted through an angular demodulator 13 to a monitor
14 in which the video signal is converted to a visual display
corresponding to the document D. It will be apparent that the visual
display of document D at monitor 14, that is, a still picture of the
document, can be maintained for as long as desired by reason of the
recording of the corresponding video signal in storage device 12.
Alternatively, as shown, the video signal can be transmitted directly from
modulator 11 through demodulator 13 to monitor 14, whereby to display a
picture of document D at monitor 14 so long as an image of such document
is being picked up by camera 10.
The angularly modulated video signal is further transmitted through a
recording amplifier 15 and a recording and play-back switch S, when the
latter is in its recording position R, as shown, to a magnetic recording
and reproducing unit generally identified by the reference numeral 16. A
particular embodiment of the magnetic recording and reproducing unit 16
according to this invention will now be described with reference to FIGS.
2 and 3. As shown, such unit 16 generally includes a magnetic recording
medium in the form of a tape T movable along a path between supply and
take-up reels (not shown) and being guided in such path, as by guide posts
or rollers 17a, 17b, 17c and 17d, to wrap partially around the periphery
of a cylindrical guide assembly 18, with the guide posts 17b and 17c being
displaced relative to each other in the axial direction of cylindrical
guide assembly 18 so that planes normal to the axis of guide assembly 18
are disposed obliquely with respect to the direction of movement of tape T
between guide posts 17b and 17c. As shown, guide assembly 18 includes a
middle cylindrical part 18a and cylindrical parts 18b and 18c which are
spaced axially, and aligned with middle cylindrical part 18a so as to
define annular gaps 19a and 19b between part 18a and parts 18b and 18c,
respectively. One or more video signal magnetic recording and reproducing
heads, for example, the diametrically opposed heads 20a and 20b, are
mounted to extend through gap 19b for rotation in a plane that extends
obliquely with respect to the direction of movement of tape T on
cylindrical guide assembly 18. As shown, heads 20a and 20b may be mounted
at the ends of a support arm 21 which, at its center, is supported on a
shaft 22 which is coaxial with cylindrical guide assembly 18 and driven by
a motor 23. The heads 20a and 20b are displaced a small distance from each
other in the direction parallel to the axis of shaft 22 so that, during
each revolution of shaft 22, for example, at a rotational speed of 30
revolutions per second, heads 20a and 20b will scan slightly spaced apart,
stripe-like areas of the tape extending thereacross obliquely with respect
to the longitudinal direction of movement of the tape, for example, the
stripe-like areas Va and Vb, respectively, shown on FIG. 1.
The rotation of heads 20a and 20b by motor 23 is synchronized with the
scanning of document D by camera 10 and also with the rotation of the
magnetic disk 12a of storing device 12 so that the time for a revolution
of shaft 22 will correspond to the time for a video signal corresponding
to the complete document D. As shown on FIG. 4, heads 20a and 20b are
connected to recording and play-back switch S so that, when the latter is
in its recording position R, the video signal corresponding to a single
frame, that is, to the complete document D, will be recorded in the
stripe-like areas Va and Vb of the tape which are scanned by the heads 20a
and 20b, respectively.
As shown on FIG. 1, the magnetic tape T has index signals N.sub.1, N.sub.2,
N.sub.3 etc., recorded thereon at intervals in the direction of movement
of the tape and each corresponding to and identifying a video signal
recorded, or to be recorded, in tracks extending obliquely to the
direction of tape movement similarly to the stripe-like areas scanned by
heads 20a and 20b. The video signal recorded in each pair of oblique or
skew tracks represents one document page or other visual information which
is to be recorded and then retrieved and displayed at monitor 14. As
disclosed in my previously mentioned copending application Ser. No.
591,596, all of the index signals may be the same, in which case each
video signal is identified by the number of its corresponding index signal
counted from one end or the other of tape T, and any particular video
signal can be located merely by moving the tape and counting the index
signals as reproduced by a fixed magnetic head 24 (FIGS. 3, 4 and 5) until
the number of such signals corresponds to that of the index signal
identifying the desired video signal. As shown on FIG. 4, the tape T may
be moved in either direction by means of a capstan 25 cooperating with a
pinch roller 26 and being driven by a motor 27 under the control of a
control circuit 28. The index or address signals on tape T, as reproduced
by head 24, are detected by a circuit 29 and converted into a suitable
wave form by a circuit 30 before being fed into control circuit 28. The
control circuit 28 also receives, at a terminal 31 thereof, a suitable
request signal corresponding to a selected portion of tape T in which a
video signal is to be recorded, or from which a video signal is to be
reproduced. Within control circuit 28, a suitable reversible counter which
receives the signals from circuit 30 provides a tape position indicating
signal, and also a comparator circuit which compares such tape position
indicating signal with the request from terminal 31 and, in dependence on
their relative magnitudes or other characteristics, issues suitable
signals for controlling the operation of motor 27. Thus, when a request
signal corresponding to a particular portion of tape T is fed to control
circuit 28 and such portion of the tape is not disposed at the recording
and reproducing station or unit 16, motor 27 is operated to move tape T
until head 24 detects the index signal which corresponds to the location
of the desired tape portion at unit 16, whereupon operation of motor 27 is
halted.
With the tape thus positioned, motor 23 is operated to cause heads 20a and
20b to record a video signal in the stripe-like areas Va and Vb of such
tape portion, when recording is being effected, or to cause the heads 20a
and 20b to successively reproduce the video signal previously recorded in
the stripe-like areas Va and Vb of the tape portion then positioned at the
recording and reproducing station. As previously mentioned, the rotation
of heads 20a and 20b is synchronized with the operations of camera 10,
storing device 12 and monitor 14, and such synchronization may be
conveniently effected by means of synchronizing pulses produced by a
generator 32 (FIG. 2) which is constituted by a fixed magnet 32a mounted
for rotation with shaft 22 and a magnetic head 32b which is fixedly
located adjacent to the circular path of travel of magnet 32a.
When a video signal previously recorded in stripe-like areas Va and Vb of a
selected portion of tape T is to be reproduced, tape T is again moved, as
described above, to locate the selected tape portion at the recording and
reproducing station, and heads 20a and 20b are rotated with switch S in
its play-back position P so that the desired video signal, as reproduced
by heads 20a and 20b is transmitted through a play-back amplifier 33
either to storing device 12 or directly through demodulator 13 to monitor
14 for display of the corresponding picture at the monitor. It will be
apparent that, so long as tape T remains at the selected position and
heads 20a and 20b are continuously rotated, the video signal recorded on
the selected portion of the tape will be repetitively reproduced so as to
provide a constant display of the respective image or picture at monitor
14. Alternatively, once the reproduced video signal is recorded in storing
device 12, tape T can be moved from the selected position and the
reproduced video signal can be repetitively supplied to monitor 14 from
storing device 12 so as to provide a continuous display of the respective
image at the monitor.
In accordance with the present invention, the recording and reproducing
unit 16 further comprises one or more audio signal magnetic recording and
reproducing heads, for example, the diametrically opposed heads 34a and
34b, which are mounted to extend through gap 19a for rotation in a plane
that extends obliquely with respect to the direction of movement of tape T
on cylindrical guide assembly 18, and which is parallel to and spaced from
the plane of rotation of heads 20a and 20b. As shown, heads 34a and 34b
may be mounted at the ends of a support arm 35 (FIGS. 3 and 5) which, at
its center is supported on a shaft 36 which is coaxial with cylindrical
guide assembly 18 and driven by a motor 37. The heads 34a and 34b are
displaced a small distance from each other in the direction parallel to
the axis of shaft 36 so that, during each revolution of shaft 36, for
example, at a rotational speed of 1/20th of a revolution per second, heads
34a and 34b will scan slightly spaced apart, stripe-like areas of the tape
extending thereacross obliquely with respect to the longitudinal direction
of movement of the tape, for example, the stripe-like areas A.sub.a and
A.sub.b, respectively, shown on FIG. 1.
The heads 34a and 34b are both selectively connected through a recording
and play-back switch S.sub.1 either to an amplifier 38 connected to a
microphone 39 or to an amplifier 40 connected to a loudspeaker 41. Thus,
when switch S.sub.1 is in its recording position R, heads 34a and 34b are
made operative to magnetically record audio signals in stripe-like areas
A.sub.a and A.sub.b, respectively of the tape portion there disposed at
the unit 16, which signals correspond to sounds picked-up by microphone
39. On the other hand, when switch S.sub.1 is in its play-back position P,
heads 34a and 34b are made operative to reproduce the audio signals
previously recorded in the stripe-like areas A.sub.a and A.sub.b there
being scanned by such heads, and the reproduced audio signals are
translated into the corresponding sounds by loudspeaker 41.
Synchronizing pulses may also be produced by a generator 42 (FIG. 2)
constituted by a permanent magnet rotated with shaft 36 and a magnetic
head fixed adjacent the circular path of such magnet to provide a pulse
during each revolution of the shaft. Such synchronizing pulses from
generator 42 may be employed to synchronize the recording and reproduction
of the audio signals during the relatively slow rotation of heads 34a and
34b with the recording and reproduction, respectively, of the video
signals during the relatively high speed rotation of heads 20a and 20b.
By reason of the slow speed rotation of heads 34a and 34b by motor 37,
sounds of relatively long duration can be recorded in, and reproduced from
the two stripe-like areas A.sub.a and A.sub.b in each selected portion of
tape T. Thus, for example, if the tracks or stripe-like areas A.sub.a and
A.sub.b have a combined length of 50 cm., that is, 25 cm. per track, and
if shaft 36 rotates at a speed of 1/20th revolution per second, the
recording speed is 2.5 cm./sec. and the tracks A.sub.a and A.sub.b will
accommodate a recorded sound having a duration of 20 seconds.
During the reproduction of sounds of such duration, the video signal
representing the corresponding picture or visual information is
repetitively supplied to monitor 14 preferably from storing device 12, or
alternatively from heads 20a and 20b. In the case where heads 20a and 20b
are rotated at a speed of 30 revolutions per second and heads 34a and 34b
are rotated at 1/20th revolution per second, as mentioned above, the video
signal will be supplied to monitor 14 600 times during the reproduction of
the sound of 20 seconds duration. Thus, it is preferred that the
reproduction of the video signal by heads 20a and 20b occur only during a
single revolution of such heads, with the reproduced video signal being
recorded in storing device 12 for repetitive supply therefrom to monitor
14.
It will be apparent that with the system described above, video signals and
audio signals corresponding to large numbers of still pictures or visual
information and related sounds can be recorded on a single tape and
immediately retrieved for simultaneous reproduction. Such system obviously
is ideally suited for educational and informational purposes as well as
for use as an advertising device.
Although illustrative embodiments of the invention have been described
herein with reference to the accompanying drawings, it is to be understood
that the invention is not limited to those precise embodiments and that
various changes and modifications may be effected therein by one skilled
in the art without departing from the scope or spirit of the invention as
defined in the appended claims.
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