Dual deck videocassette recorder system

Dual deck videocassette recorder system
United States Patent 1191
[11] Patent Number:
Dunlap et al.
[75] Inventors: R. Terren Dunlap, Scottsdale; John
B. Berkheimer, Tempe, both of Ariz.;
C. Duane Woodmas, Empgria, K3115,
Date of Patent:
Mar. 16, 1993
9/1983 Sakamoto .................. .. 360/7716 X
3/ 1987
4,768,110 8/1988 Dunlap et al. ................... .. 360/331
[73] Assignee: Go-Video, Inc., Scottsdale, Ariz.
Appl. No: 230,181
2013865 2/1933 United Kingdom ................ .. 360/15
Int. Cl.5 ....................... .. H04N 9/80; H04N 9/88
United Kingdom ................ .. 360/3l
Aug. 9, 1988 1
[52] U.S. c1. .................................. .. 353/314; 358/316;
Sharp M°d=1VC—5W20E owner’s Manual, May 1988
358/321; 358/343; 360/15; 3160/38.]; 369/84
[58] Field of Search ................... .. 358/181, 191.1, 314,
358/315, 316, 318, 321, 335, 341, 343;
5'9"”? lii‘am'f'eklzgylgl-fnvani J‘
“mm x“'"‘"e’—, -
360/l4_1_14_3 15 33.1 3&1 61_63 7102
73.04, 73.11, 77.12-77.14, 77.16; 369/6-7, 12,
References Cited
Attorney, Agent, or F1rm—Jerry Cohen; Harvey Kaye;
Edwl" H- Paul
A videocassette deck and taping system includes two
videocassette decks therefor (A and B) included within
3 560 666 2/1971 Bookman ...................... .. 369/7
a Single housing utilizing 3 “mm” Pow‘:r supply’
316201476 11/1971 Cervantes
v360/15, x
tuner, controls, and switching and control circuitry to
........ .. 360/15
enable simultaneous multiple functions using both decks
360/7311 X
and to also enable tape to tape duplication (dubbing) in
gamml ------------------ -- 32%;}?
a manner avoiding degradation of video information
""""" '
3,767,206 10/1973 Rehklau et a1. .
4,224,643 9/1980 Nakano et a1. .... ..
............. ..
4,276,562 6/1981 stcwan at a]. .
369/7 X
8/ 1983 Nishimura ct a1. .
369/7 X
8/1983 Yamamitsu et al_ .............. .. 358/318
content, as well as additional funct1on select1on.
2 Claims, 9 Drawing Sheets
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US.‘ Patent
Mar. 16,1993
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US. Patent
Mar. 16,1993
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home-consumer uses (i.e., expensive, occupied too
This invention relates to a dual deck videocassette
recorder (“VCR”) system that enables the user to have
two decks available for selective simultaneous func
tions, including playback and recording capability of
the system such that pre-recorded material can be trans
ferred from a videocassette tape in one such deck to a
blank tape in the other deck. Related subject matter
in the Dunlap-Lang application, Ser. No.
07/048,521, ?led May 8, 1986 (as a continuation of Ser.
No. 06/652,820, ?led Sep. 20, 1984, now abandoned),
and now U.S. Pat. No. 4,768,110, granted Aug. 30, 1988.
The present invention provides an integrated (single
much space-large footprint, cumbersome, complicated
to use, short recording time capacity). This capacity
problem and some portion of the other shortcomings
were caused by the excessive space required in the
recording method used to lay the signal on the video
tape. Space needs were generated by (l) the large size of
the recording heads’ gap (85 microns) and (2) the neces
sity of a guard band (the unrecorded space or distance
between the recorded information of the video track)
on the tape to prevent “cross-talk.”
Although azimuth recording was patented in 1958 it
wasn’t perfected until 1974 when Sony introduced the
Betamax brand i-inch VCR designed for the home
set) dual-deck VCR system usable with a fully featured
consumer and comprising the feature that slant azimuth
recording was incorporated into videocassette record
ers by using smaller narrow gapped heads (58 microns).
Azimuth recording uses two heads mounted with head
gaps at angles slightly off perpendicular to the head
television set or with one or more components of a
path (at a six degree angle to true perpendicular to
video system (e.g., antenna, monitor, tuner) enabling
direction of the head), one slanted to the left and the
play of a pre-recorded videocassette tape from one deck
other to the right. This azimuth head con?guration
chassis, single tuner, single power supply, single control
of the dual deck VCR system to an associated television
reduces cross-talk and eliminates the wasted, unused
set or monitor while simultaneously recording an off
space that was required on the bulky commercial
the-air broadcast to a videocassette tape in the other 25 VTR’s and 2-inch VCR’s.
deck of the dual-deck VCR system.
One of the features of the present invention is the
ability, in context of a dual-deck VCR system, to dupli
cate “high quality” videocassette tapes (speci?cally,
those videocassette tapes with azimuth recording char
acteristics as used in home-consumer VCR’s) with good
Matsushita and Victor Company of Japan (JVC)
immediately introduced their version of a consumer
VCR format, viz: 5-inch VHS (Video Home Systems),
which incorporated the azimuth recording system but
also extended the recording time to six hours using
T-120 tape or eight hours using T-l60 tape. This was
accomplished by using a smaller recording head gap (29
microns), by creating a one-half track width and by
?delity and avoidance of copy degradation where a
slowing down the running speed of the tape.
copy is made from a copy in two or more generations. 35
VCR technology was then commercially practicable
A further feature of the invention is the maintenance
of the integrity of pre-encoded copyright protection
systems in a manner that makes defeat of protection
systems by ordinary consumer devices (generally re
ferred to as “video stabilizers” or “black boxes”) im
The user of the consumer grade azimuth-recorded
at a consumer market level as the cost had been re
duced, the machines were smaller, the cassettes were
pocket book size, the loading of tapes and operations
was now simple and a long series of television programs
could be recorded. With the addition of a tuner/timer,
time shifting was available so the user could watch
programs during leisure time.
videocassette tapes can, with this invention, simply and
The introduction of VHS and Beta for consumer
easily duplicate (or dub) tape contents from one (source
of broadcast television shows immediately
tape) to the other (target tape) through FM dub cir 45
raised the question of legality of selling the VCR ma
cuitry provided in this invention to achieve a clear,
chines, which was resolved by a U.S. Supreme Court
high-quality, videocassette target tape which is indistin
decision in 1984 (Sony Corp. of America v. Universal
guishable from the original (source) videocassette tape.
Studios, 464 U.S. 417 (1984), favor of continued sale.
Further, several generations of duplicated videocassette
The door was opened for order of magnitude expansion
tapes maintain the high quality visual characteristics of
the original videocassette recording.
Azimuth-recorded videocassette tapes can, with the
present invention, be pre-encoded with a signal (or
various signals) that actuate the circuitry of the dual
deck VCR system to prevent the duplication of said
tapes (through a closed, sealed circuit device which
makes it impracticable and cost prohibitive for the con
sumer to bypass this system and impossible to use a
video stabilizer and still maintain the quality as pro
vided by the dub circuitry of- the invention).
Commercial “reel-to-ree ” videotape recording
(VTR) was introduced to the public by the U.S. com
in the U.S. sale of VCR’s. This was followed by a prolif
eration of videocassette recordings from various
sources (i.e., home movies, business productions, educa
tional programs, news releases, etc.) and many VCR
owners began wiring their single deck machines to-'
gether to make copies of their tapes. However, the
quality of the copies made by wiring two VCR’s was
and is marginal.
A major problem of such copying was and is the
inability to effectively transfer an azimuth recorded
video signal and lay it on a blank tape in the same azi
muth format without loss of signal, the creation of noise
and the experience of severe degradation of signal. Sev
pany, Ampex, Inc., in 1956. In 1969 Sony Corporation
eral efforts of the art to solve the problem included
(Japan), and its U.S. marketing subsidiary, introduced
the ?rst 2-inch U-Matic “videocassette” recording 65 video enhancers, detailers and other such means to ?ll
(VCR) unit for commercial broadcast TV studio re
cording purposes. These systems although excellent for
broadcast TV studio purposes had major drawbacks for
in or alter signals but none of these devices could “save”
the original azimuth recorded signal in an unaltered
state for duplication of like kind and quality.
5, l94-,963
break or wear in the wire which can permit interference
llt is, therefore, the object of the present invention to
in the signal transferred. The connectors can easily
overcome the prior-art drawbacks of dubbing technique
and apparatus.
become damaged or worn or broken through constant
use or misuse and, therefore, cause interference in the
It is a further object of the invention to enhance the
usefulness of videocassette recorder (VCR) systems.
signal transferred.
It is a further object of the invention to provide a low
cost, mass-marketable dual deck videocassette recorder
system which is easy to understand and use, reliable and
The present invention is directed to a videocassette
recorder and taping system which includes at least two
multi-functional, with a range of selectable useful opera
tions for entertainment, educational and/or business
tape therein. An output selection switching means is
provided for selection of the video output to a video
monitor from among a plurality of signals including the
videocassette recorder decks receiving videocassette
signal from a videocassette tape in either of the ?rst or
the second decks and the input to the ?rst VCR. Other
The present invention which solves the above de
standard signals which may be selectively directed
scribed tape duplication problems is related to the fol 15 through the output selection switch include a TV tuner,
a video line, and a camera. A second selection switching
lowing retrospective analysis made with bene?t of the
means is also provided for selecting the desired record
present invention itself. The major road block of the
ing input when one of the lines connected to this switch
state—of-the-art was created by the modulation and de
is also connected directly to the second videocassette
modulation process which is inherent in any single deck
consumer 5-inch VCR. Conventional single deck 20 deck. Thus, a prerecorded tape that is located in the ?rst
videocassette deck may be recorded on a blank video
VCR’s modulate outgoing signals to prepare the signal
cassette tape located in the second videocassette deck
while selection of a program for monitor viewing is
unrestricted among the original alternatives. It is also
for transmission to the monitor and demodulate incom
ing signals to prepare the signal for azimuth recording
on the tape. Therefore, the conventional method for
duplicating videotapes from one VCR to another (i.e., 25 seen that the proposed system provides the signi?cant
advantage that a prerecorded tape may be viewed dur
VHS to VHS, Beta to Beta) was accomplished by in
ing a recording session.
serting a pre-recorded cassette into one VCR and a
' The complexity and problems that exist with cabling
blank tape into a second VCR. The video “out” from
and jacks can be eliminated with internal wiring but
the ?rst VCR was cabled to the video “in” of the sec
ond VCR and the separate recorders were turned on. 30 only through the creation of a dual-deck VCR system
The second VCR was programmed to record informa
tion input to it and the ?rst VCR was programmed to
play the information recorded on it. When the VCRs
were run, the information of the cassette in the ?rst
VCR was recorded onto the cassette in the second 35
with internal circuitry. The primary problem remains
unresolved, “How can one eliminate the degradation of
signal caused by modulation and demodulation and still
prevent ‘crosstalk’ because part of the color process in
converting from 629 KHZ to 358 MHZ helps eliminate
the crosstalk?” This is required to process out the inter
ference in the color signals to ensure quality and, there
fore, preclude the ability to record color 629 KHZ to
color 629 KHZ directly. It has been determined that the
VCR, making a duplicate.
Another approach is to track the above process, with
the exception that the corresponding RF or radio fre
quency is used as output and input. This alternative is
less preferred since additional processing of the video 40 circuitry could be designed with minimal processing
and maintaining a clean FM/629 dub transfer process
which would allow the recording tape to preserve the
signal is used to modulate the RF carrier output which
is directly demodulated by the receiving VCR to pro
duce the video again. This unnecessary modulation and
demodulation further degrades the signal quality of the
duplicate tape.
original high de?nition signal coming from the prere
corded tape. An FM/629 dub circuit provided in accor
Apparently, video is used because that is what most
VCR manufacturers provide as convenient output
jacks. But successive duplication from tape to tape to
tape and so on, using these artifacts, is detrimental to the
dance with the present invention comprises, primarily,
an automatic gain control (AGC) ampli?er, a dropout
compensator with delay line, a buffer and then a high
pass ?lter to separate luminance for passage through a
limiter and equalizer plus a low pass ?lter to separate
quality of the signal recorded, although less so than 50 the color for passage through an AGC amp and then
when using the RF outputs and inputs. The deteriora
recombination with the luminance in a buffer. It was
tion in signal quality is due to the same reasons. The
video signal, as de?ned in many handbooks, is not di
rectly recorded onto the tape. Instead an PM or fre
further discovered that the original azimuth recorded
quency modulated signal is recorded onto the tape. 55
Thus when a duplicated tape is made by using the video
signals, there is an unnecessary and redundant forma
tion of the video from the FM and then the FM from
the video which degrades the resultant signal recorded
on the duplicated tape.
This use of cabling from one VCR to another
(whether through video jacks or through RF jacks)
creates a system of exposed connectors and cables.
These connectors and cables are subject to several in
signal could be substantially maintained using the
smaller (29 micron) heads at the standard play (SP-2
hours) speed because a guard band is created and, there
fore, less processing is required.
Another unresolved problem that this invention ad
dresses is the ‘policing’ of unauthorized duplications of
copyrighted Videocassettes. Copy-coding systems are
being marketed and employed to protect encoded copy
righted videotapes from illegal or unauthorized copy
Currently, all duplication of videocassette tapes is
accomplished by cabling together two single deck
herent shortcomings and problems. The length of the 65 VCRs. However, in response to video copy-coding
systems, “video stabilizer” systems have been devel
cables promotes degradation and interference of signals
by picking up unwanted signals and the cables through“ oped to interfere between the two single VCRs via the
cabling system. The explicit purpose of “video stabal
exposure or use can become easily damaged causing a
dual deck system providing off-air taping and play con
trol and utilizing duplicating fetures hereinafter de
scribed and generally indicated at 10. The system 10 is
contained within a single housing generally indicated at
izer” devices is to intercept the video signal and un
scramble the copy-coding system. Thus, the present
method for duplicating videocassette tapes can be
readily con?gured to defeat copy-coding systems.
The editing and duplication in the invention, dual
deck FM dub VCR, is accomplished through the inter
11 and, as will be described, includes a dual deck ar
rangement for receiving conventional videocassette
tape therein. The term “deck” as used herein comprises
a platform for a videocassette, hubs for engaging drive
wheels of the videocassette, motor means for driving
one or both hubs, motor controls and electromagnetic
electrostatic and/or optical transducer heads for ex
nal circuitry of the system. Any attempts by a home
consumer user to intercept the video signal through
external cabling will be unsuccessful for three reasons:
?rst, an external signal would have to pass through the
demodulation-modulation process and would not be of
change of control signals and information with the vid
original high quality for duplication process. Secondly,
eotape medium of the videocassette. Each deck has an
access port-12 for ?rst deck A and 14 for second deck
within the play machine electronic circuitry by the
‘play’ machine which will instruct‘the ‘record’ machine 15 B. A ?rst deck (designated as deck A in FIG. 1) may be
used for playing a prerecorded video tape located in a
to scramble or not record the signal. Thirdly, the video
cassette. A second deck (designated by deck B in FIG.
stabilizer cannot be plugged into the sealed integrated
1) is used also for playing and recording videocassettes.
circuits of the dual-deck VCR without substantial engi
An output selection switch 18 is located on the front of
neering, tooling and understanding and impracticable
20 the housing 11 below the port 12 and, as will be de
scribed, selects a line which will be connected to the
The combination of the dual-deck con?guration and
video monitor for viewing. A recording selection
the FM dub feature with video copy-coding systems
switch 18 is also located on the front of the housing 11
serves to provide signi?cantly greater protection
the copy code will be read by a sealed integrated circuit
against unauthorized copying of encoded videocassette
Other objects, features, and advantages will be appar
ent from the following detailed description of preferred
embodiments taken in conjunction with the accompany
ing drawings in which:
FIG. 1 is a front view of the control panel and hous
ing of a dual deck VCR utilizing features of the present
below the port 14 and is provided for selecting the input
25 line from which a program or prerecorded material will
be recorded onto a blank video tape cassette that has
been inserted into deck B(14). The recording selection
switch 16 is only used when a blank tape is inserted into
port 14, deck B.
therefor is schematically illustrated and in this connec
tion it is understood that the electrical components, as
invention, according to a preferred embodiment ‘
FIG. 2 is a circuit block diagram of a dual-deck VCR
system of the present invention which can be associated
Referring now to FIG. 2, the videocassette deck and
taping system according to a ?rst preferred embodiment
illustrated in block diagram form, are composed of
35 conventional circuitry well known in the art except as
otherwise speci?ed herein. As shown in FIG. 2, the
electrical inputs into the system include a TV signal that
is directed through a TV tuner 20, a video input that is
directed through an isolation ampli?er 22, a camera
FIG. 3A is a circuit block diagram of a dual-deck
VCR system of the present invention which can be 40 video input socket 24, and (also as an “input”) the ?rst
videocassette deck (Deck-A). All of the input signals
_ associated with the FIG. 1 control panel and housing
are selectively directed into the ?rst video cassette deck
(but in a different preferred embodiment construction
with the FIG. 1 control panel and housing;
relative to FIG. 2);
(Deck-B) that is accessed through the port 14 for re
cording onto a blank tape located therein. A ?rst four
circuitry utilized with Deck A of FIG. 3A; FIG. 3C 45 position (1, 2, 3, 4) selection switch 16 can direct a
selected one of the inputs to deck B and simultaneously
shows a more detailed level of the FIG. 3B circuitry
to a second (output) switch 18 (with positions 1-6).
utilized with Deck B of FIG. 3A;
The input signals may also be directed to the TV
FIGS. 4A-4C show the organization of information
monitor for video display thereon. For this purpose, the
recorded onto magnetic videocassette tapes in speed
output selection switch 18 through the switch positions
modes of SP and EP respectively;
1-6 thereof is moved to the appropriate position for
FIG. 5 is a block diagram of a duplicating sub-system
selecting the desired signal among the six inputs for
usable with various embodiments of dual-deck VCR
connection to the TV monitor. As shown in FIG. 2, the '
systems, e.g., the one shown in FIG. 3A, showing the
FIG. 3B shows a more detailed level of the FIG. 3A
relationship of the duplicating circuitry and the play
output line from the second videocassette deck B as
and record heads and the formation of the synchronous
signals used for the motors which drive the videocas~
sette tape on which information is being recorded (tar
selected by the output switch 18 is connected through
switch position #6 thereof to the video monitor for
set taP6);
FIG. 6 is a circuit block diagram of the FM dub
processing portion of the duplicating circuitry of FIG.
4; and
viewing the program material of a videocassette in deck
The combination of the selection and output
60 switches, 16 and 18, enables a versatility of operation
that includes use of the selection switch 16 to record
either a TV program through the TV tuner 20 that is
connected to selection switch position #4, a video input
external controller means.
that is connected to selection switch position #3, or a
DETAILED DESCRIPTION OF PREFERRED 65 camera input that is connected to selection switch posi
tion #2, while at the same time viewing on the TV
monitor a prerecorded tape that has been inserted into
Referring now to the drawings and particularly to
port 12 of Deck-A and by activating the play function
FIG. 1, the housing and front panel of a videocassette
FIG. 7 is a system block diagram modi?ed to include
on Deck-A and movement of the output switch 18 to
position #4. It is also possible by use of the subject
invention to duplicate material as prerecorded on a tape
that is inserted into the videocassette recorded at port
12 of Deck-A by locating the selection switch 16 at
position #1 while displaying the prerecorded program,
which is accomplished by locating output switch 18 at
position #5. In this manner, the material prerecorded on
the for example, by leaving out commercials, on a blank
cassette tape located in Deck-B. The videocassette lo
dual purposes of playing or recording as in FIG. 3. The
functional keyboard can be programmed to either play
or record from the VCR-A circuit. A frequency modu
lated (FM) signal, 159 can be recorded onto a tape
videocassette tape loaded into deck VCR-A via switch
169 and the heads 196 on drum 194. A second FM signal
170 can be selected for recording through switch 169.
This second signal is formed by modulating an input
video signal 158 with the Y/C Modulator/Processor
cated in Deck-A can then be viewed while the edited
164. The Y/C modulator/processor 164 transforms the
video into an FM signal suitable for recording onto
version is produced in Deck-B.
magnetic tape by conversion of the Y signal to FM,
Referring now particularly to FIG. 3, a second em
bodiment of a dual-deck VCR system's basic circuit is
which is well known in the art. The PM signal on the
tape is a luminance, referred to as Y, signal. The tape
also contains a chrominance signal (C), which is a het
diagramatically illustrated in which the ports 26 and 28
provide access to decks A and B, both of which com
erodyned color signal in accordance with NTSC Stan
prise VCR play and record capability and may be con
dard (phase and amplitude modulated). Heterodyning
mixes two higher frequency signals, producing a lower
frequency signal equal to the difference between the
TV tuner 20 for receiving a TV signal, a video input 20 two higher frequency signals wherein all the informa
tion contained in the higher frequency signals is pre
that is directed to the isolation ampli?er 22, and a cam
served in the side bands of the lower frequency signal.
era video input that communicates with the system
The Y signal which carries all the luminance and TV
through the socket 24. In order to select the input into
de?ection synchroniztion information, is direct FM
VCR-A, a ?rst (selector) switch 30 is provided and
modulated on a carrier to a frequency spectrum above 1
includes switch positions numbers 1-4. Switch position
MHZ. The C signal carries the color information and is
#1 for selection switch 30 directs the signal from the
?gured for similar or different VCR formats. VCR
deck-A (V CR-A) is adapted to communicate with the
TV tuner into VCR-A. Switch position #2 directs the
signal from the isolation ampli?er 22 into VCR-A, and
switch position #3 directs the signal from the camera
video into VCR-A. A second (output) switch 32 and
switch positions 1-4 therefor are disposed in parallel
relation with respect to switch 30 and the switch posi
heterodyned into a frequency spectrum below 1 MHZ.
These two signals are separated by a high pass ?lter and
tions thereof and directs the signals from the inputs into
VCR deck B (VCR-B). Thus, the input signal from the
158. This information is input to a servo control 191
which forms that signal which drives the drum motor
176 and the capstan motor 178 which drive the drum
TV tuner is directed to VCR-B through switch position
#1 of the selection switch 32, while the signal from the
isolation ampli?er 22 is directed to VCR-B through
switch position #2 of the selection switch 32, and
switch position #3 directs the signal from the camera
video to the VCR-B.
Both VCR-A and VCR-B are arranged to not only
record but to play back. One purpose of the dual system
as illustrated in FIG. 3 and as described hereinabove is
a low pass filter. The Y-FM/C629 signal 159 has corre
sponding parts.
The Y/C modulator/processor also extracts the ver
tical synchronization information from the video signal
194 and the capstan, respectively. All the resulting sig
nal recorded on the tape must be synchronized in order
to produce a tape suitable for viewing.
When a VCR tape is played on deck VCR-A the FM
signal is buffered by the ampli?er 192 and can be sent
out through switch 195 or through the Y/C demodula
tor/processor 160 which reproduces the video 162.
The description of FIG. 3B for the circuit of deck
VCR-B, corresponds to that of VCR-A (FIG. 3A).
to enable a VHS cassette as located in VCR-A to record
information from a Beta tape as located in VCR-B. The 45 Consider a pre-recorded tape loaded in deck VCR-A
contrary circumstances are also available, wherein a
and a blank videocassette tape in deck VCR-B and the
Beta system with a Beta tape located in the deck of
function keyboard 197 being programmed to duplicate
VCR-B can record information from a VHS tape as
from the videocassette tape in deck VCR-A.
located in the deck of VCR-A. Switch position #4 in
both of switches 30 and 32 provide for connecting the
output of VCR-A with VCR-B, or conversely, connect
ing the output of VCR-B to VCR-A. Thus, it is possible
recorded on a magnetic tape with and without utiliza
tion of the present invention is shown. The signal on
to record (“dub”) video/audio information from a tape
located in VCR-A onto a tape located in VCR-B; con
versely, it is possible to record such information from a
source tape located at VCR-B onto a target tape located
at VCR-A. The system can also be used for simulta
neously recording from a broadcast or auxiliary input to
the videocassette tapes in both decks. The above de
scribed structure can also be used with minor modi?ca
tion, now apparent, to dub between source and target
tapes of different formats or to apply an external source
Referring to FIGS. 4A-4C, the format of signals
tape 300A, 300B, sooc (of FIGS. 4A-4C, respectively) I
has three parts. The audio signal is recorded on 1-2
audio-tracks (302) at the speci?ed level using an AC
bias current recording system. The control track 303 is
recorded along the other edge of the tape and contains
the vertical synchronization signals. Each video track
306 contains one complete TV ?eld including the lumi
nance, chrominance and the TV de?ection synchroni
zation signals. Track 308 contains the successive TV
?eld information following 306. In the prior art situa
tion of FIG. 4A, the two tracks 306 and 308 are physi
tapes of different formats at the two decks. The avail
able formats include, but are not limited to, 8 MM,
cally adjacent and tend to overlap (either physically
overlap or virtually overlap-Le, where the magnetic
?eld effects of adjacent tracks overlap). This situation
VHS, S-VHS, Beta, ED-Beta.
of FIG. 4A occurs under the conditions of standard
FIG. 3A shows the functional blocks needed for the
tasks using each of ‘VCR-B and VCR-A decks for such
heads. HG. 4B illustrates this same relationship under
signal for recording simultaneously to videocassette
play (SP) tape speed using standard play (SP) recording
the conditions of extended play (EP) tape speed using
extended play (EP) recording heads. Both FIGS. 4A
and 4B illystrate that no guard band exists between
recording tracks, and in fact physical or virtual overlap
of these magnetic ?elds occur in both of these condi
A signi?cant improvement in this condition is
achieved by this invention. FIG. 4C illustrates that
guard bands are established between sequential record
ing tracks 306 and 308. This eliminates the physical or
virtual overlap of magnetic ?elds and resultant degrada
tion of information. The new topographical relationship
is accomplished under the condition of standard play
(SP) tape speed using extended play (EP) recording
heads, the the FM signal dub process as described here
inafter. However, it is the establishment of the guard
band which enables practical utilization of FM dubbing.
Such utilization, in turn, enables a system which affords
response to the average signal rising or lowering. The
resulting signal is fed to a “drop out copensator" 114.
The circuitry includes a delay line 116 where the previ
ously received FM signal, which is equivalent to one
TV horizontal line, is stored. If a “drop out” or loss of
signal is detected the information stored on the previous
line replaces the lost information until the “drop out”
disappears. This signal is buffered by 118 and fed to the
Y/C processor 160 (FIG. 4) on line 140 (FIG. 5) and
also fed through a signal splitter represented by the
resistors 120 (FIG. 6). The circuitry following this sig
nal splitter processes the FM signal to prepare the sig
nals for recording onto another videocassette tape.
As described above the FM signal on the tape has
two parts, the luminance and the chrominance, which
are easily separated by ?lters. The chrominance (color)
carrier at 629 KH is separated by a low pass ?lter 130
and sent through the AGC ampli?er 132 where the
signal level can be set by a color level control 133.
generational losses and avoiding cost, complexity and 20 The high pass ?lter 122 separates out the luminance
FM signal, which passes through a common FM limiter
ccunterproductivity of additional modulation (coding).
repeatable high ?delity of dubbing avoiding progressive
/demodulation (decoding) subassemblies.
124. This removes any amplitude variations from the
The FM signal from the pre-recorded tape is read by
FM luminance signal preserving only the frequency
described below. The play out signal 140 from the dub
processor 111 is fed back through switch 195 to the Y/C
teristic that higher frequency signals will have a higher
amplitude when read from the tape than lower fre
quency signals all else remaining constant. The lumi
information. This signal is then fed through a common
the heads 196 (FIG. 5) ampli?ed and buffered by play
amp 192 and fed to the dub processor 111, which will be 25 equalizer 126, which compensates for the tape charac
demodulator/processor 160. The resulting video signal
nance FM signal level can be set at 128 and this, to
162 is input to the Y/C modulator 264 in deck VCR-B.
This processor extracts the synchronization signals re 30 gether with the setting of the chrominance signal 133
level, can compensate for proper record level require
quired by the record mechanism. This processor also
regenerates the FM signal from the video, but this sig
ments. The levels can be set so as to ensure that the
nal is deselected by switch 269. Instead switch 269 se
lects the output from the dub processor 111 via line 138,
which is a Y-FM signal and C-629 which has not been
Both the color and luminance signals are added to
The synchronization pulses extracted by 264 are
needed by the capstan and the drum motors of deck ,,
signal when read back from the tape will contain rea
sonable levels for the color and the luminance signals.
gether through the resistors 134 and buffered by 136.
The resulting signal is suitable for direct connection to
a record ampli?er 168 as shown in FIG. 5. The resulting
VCR-B, 26 to properly synchronize the information
signal is added back with the color signal through the
being recorded onto the tape with the actual drive
mechanism. A sync signal 271 is input to the servo
other resistor 134.
FIG. 7 is a block diagram of an enhanced system
control 291 where the appropriate speci?c signals are
generated for the drum motor 276 and the capstan
form, of the previously described embodiments, in
which simple or sophisticaled editing capabilities can be
aarily demodulated and modulated.
The audio from the tape in deck VCR-A is recorded
onto the object tape in deck VCR-B via the play elec
tronics 202 and record electronics 304.
tive edit choices, text and/or graphic and/or audio
overlays, audio/video section deletions, addins and
controlled (AGC) ampli?er 112. This ampli?er 112
maintains a given signal level by changing the gain in
conversion (beginning with the readily accessible and
convertible FM signal) for computer modi?cation and
achieved (a) through an internal or external micro
motor 278, which maintain synchronization as de
processor which serves as an edit controller and
scribed earlier.
video/audio switcher; (b) via an edit controller which
The approach also preserves the copy protection
permits pre-set “in” and “out” edit points, and/or (c)
capability. It is practical and cost effective to insert a
via means permitting an automated preview of the edit
variety of copy protection means in the signal transfer
function. Additionally, the FIG. 7 system can be
path to cope with essentially unmodulated FM (apart
equipped with an interface that allows the optional use
from relatively minor modulation/demodulation associ
of an external computer for automated control of both
ated with the copy protection. The latter demodulate/
decks and all simultaneous functions. This external,
modulate (usually related only to sync’ pulses) does not
computer interface may be selected from the class com
diminish the FM signal quality and (re)recording
prising but not limited to RS 232, SCSI, IEEE-488, and
thereof. The video information recorded on each track
undergoes little or none of the demodulate/modulate 55 RS 422 types, or other classes of interfaces.
The forms of external control can include, e.g., jog
processes under most copy protection systems.
wheel hand controls, voice or motion activation, mouse
The FM signal 138 from the dub processor 111 is
controllers, button or switch panels, tablets, etc.
input through the switch 269 to the record ampli?er 268
The edit control, whether effected by internal or
and drives the head 296 on the record drum 294. As
external means, can be constructed and arranged to
explained above, this FM signal has not been unneces
e?'ect in/out edit points, synchronized preview of tenta
transfers, simple analog-to-digital conversion (begin
FIG. 6 shows further aspects of the dub processor. 65 ning with the readily accessible and convertible FM
signal) for computer modi?cation and digital-toanalog
The FM signal is input on line 110 to an automatic gain
digital-to-analog reconversion and restoration on an
other tape. It will now be appreciated that there is a
(c) user controlled switching means to effect selective
coupling of the broadcast signal to one of said
decks, one of said decks to the output and one deck
synergistic relation among the various elements of the
system, including the following features:
to the other,
(d) means for receiving the frequency modulated
(1) Whereas a single videocassette tape has a limited
capability to receive edit processing, transfers can
be made fron a source tape to a target tape (or from
a source tape and auxiliary inputs) to a target tape
signal from a read head within a first deck’s play
back electronics;
(e) means for storing part of said received signal, said
going from, say, Deck VCR-A containing the
part being at least equivalent to one complete tele
source to Deck VCR-B containing the target; the
vision horizontal line,
roles can be reversed, with Deck VCR-B as source
with the old videocassette tape (or a new blank one
inserted) in Deck VCR-A, now the target, for a
further series of edit steps.
(2) This pour back and forth sequence with a feasible 15
set of edit steps at each pour using a series of inex
pensive videocassette tapes and an inherently inex
(f) means for detecting when any part of said received
signal has been lost, and for replacing said lost
signal with a corresponding signal from an adja
cent previous television line from said stored sig
nal, resulting in a signal with no drop outs;
(g) means for receiving said resulting signal and for
separating the chrominance signal from the lumi
nance signal;
pensive and easy-to-understand-and-operate appa
ratus and method (for educational, entertainment 20
and/or business purposes, all feasible at mass mar
ket levels) is enabled by the low loss, dub process
(h) means for adjusting the relative amplitudes of said
chrominance and luminance signals to compensate
for tape read head output versus frequency charac
and controller accommodating capabilities, de
scribed above.
(3) Consistent with the foregoing, copy and/or non 25
edit protection can also be provided for special
classes of source tapes and the system as a whole is
also utilizable for the various basic purposes set
(i) means for combining said chrominance and lumi
nance signals;
(i) means for providing said combined signal to re
cord structure within a second deck’s recording
electronics via said switching means,
(k) means for extracting synchronization information
forth in the above cited Dunlap-Lang patent.
The above described embodiments and varriants of 30
structure, operation, features, uses and advantages can
be extended within the scope of the present invention to
from said frequency modulated source;
(1) means for forming from said synchronization in
formation synchronized drive signals for the ?rst
deck’s mechanical drive mechanisms and for main
commonly controlled arrays of Deck A/Deck B dual
taining synchronization of the record heads, cap
deck systems and/or to tri-deck, four deck, etc. systems.
It will now be apparent to those skilled in the art that 35
other embodiments, improvements, details, and uses can
be made consistent with the letter and spirit of the fore
stan motor, control head and drum motor with the
information recorded on the tracks of said video
cassette tape;
going disclosure and within the scope of this patent,
which is limited only by the following claims, construed
in accordance with the patent law, including the doc
trine of equivalents.
(m) means for synchronously recording audio from
said ?rst deck onto said cassette in said second
deck, so that resulting audio and associated video
information is synchronized as on said ?rst video
cassette; resulting in a duplicate of said ?rst video
cassette from said first deck on said cassette in said
What is claimed is:
1. A dual deck VCR system including two videocas
sette decks, each including playback electronics to ef
fect playback of audio/video/control information from 45
second deck;
(:1) means for azimuth video information recording in
the second deck; and (0) speed control means and a I
a videocassette therein using read heads and associated
frequency modulation and at least one of said decks
including means for recording such information to a
related miniaturized recording head gap of said
second deck to establish guard bands between adja
videocassette therein,
(a) means for selectively providing a playback output
2. A dual deck VCR system in accordance with claim
50 l wherein both decks are arranged with recording capa
cent tracks.
hility to serve as second declrs, each constructed and
of one or the other of said decks of the system,
arranged to generate said guard hands.
(b) means for receiving and providing a broadcast
signal to the system,
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