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Description  |
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FIELD OF INVENTION
This invention relates to electrical and electromechanical systems that
utilize a wireless infrared radiation link such as for remote control,
data communication or the like. More particularly, this invention relates
to apparatus for extending the operational range of the infrared link
itself.
BACKGROUND OF THE INVENTION
Electrical and electromechanical systems that utilize an infrared link are
generally dependent upon a line of sight path between the infrared
transmitter and the infrared receiver. In many instances, an extension of
the operational range is desirable. For example, a cable television system
with monitors in different rooms may utilize the signal from a common
selector unit. The selector unit includes an infrared receiver for
operating it. Obviously, it is often desirable to operate the selector
unit from either room, but the selector with its infrared receiver is in
one room, not the other, and consequently, out of range should the remote
control unit including its infrared transmitter be taken to the other
room. No practical solution is known. Of course, each monitor could be
provided with its own selector unit, but this obviously is expensive.
SUMMARY OF INVENTION
The primary object of the present invention is to provide a practical and
versatile means for extending the operational range of an infrared link in
a communication or data transmission system. For this purpose, I provide
an infrared detector or sensor for the remote station, a transmission
line, and an emitter located within the range of the main infrared
receiver. The detector or sensor responds to infrared radiation of the
remote control transmitter unit and converts its intelligence to a
corresponding electrical signal. The transmission line sends the
intelligence in electrical signal form to the emitter which is positioned
within range of the infrared receiver. The emitter recreates the radiation
pattern of the remote transmitter for operation of the receiver, as if the
remote control transmitter unit were close by.
In the special case of a multi-unit television system, the cable wire
itself can be used as the transmission line. Optionally, power lines,
telephone lines or other existing conductor systems can be used, providing
the various signals do not interfere, or providing isolation means are
provided. Of course, a dedicated conductor pair can always be provided.
The remote control transmitter unit used is the self same remote control
unit supplied with the apparatus. If, in addition to a television
selector, the system includes a video tape apparatus cooperable with its
own infrared remote control unit, both apparatus can be located adjacent
each other within the range of the emitter. Both remote control units, one
for the television channel selector, and one for the video cassette
recorder, can be taken to the remote room and operated by the same
extension link. The form of the signal generated by the respective remote
control transmitter unit, whatever it may be, is recreated adjacent the
corresponding receiver.
BRIEF DESCRIPTION OF THE DRAWINGS
A detailed description of the invention will be made with reference to the
accompanying drawings wherein like numerals designate corresponding parts
in the several figures.
FIG. 1 is a diagrammatic view illustrating the fundamental components of
the system incorporating the present invention.
FIG. 2 is a diagrammatic view illustrating the system used in conjunction
with a multiple unit television receiver system.
FIG. 3 is a simplified schematic diagram of a detector circuit.
FIG. 4 is a schematic diagram of a frequency splitter for use with the
system of FIG. 2.
FIGS. 5 and 6 are companion schematic diagrams showing the system used in
conjunction with a telephone type code system for control of auxiliary
equipment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The following detailed description is of the best presently contemplated
modes of carrying out the invention. This description is not to be taken
in a limiting sense, but is made merely for purposes of illustrating the
general principles of the invention, since the scope of the invention is
best defined by the appended claims.
Structural and operational characteristics attributed to forms of the
invention first described, shall also be attributed to forms later
described, unless such characteristics are obviously inapplicable or
unless specific exception is made.
In FIG. 1 there is illustrated an electrical or electromechanical apparatus
10, such as a television cable converter, a laser disk player, a sound
system or the like. The apparatus has an infrared receiver 12 that
normally cooperates with a remote control infrared transmitter 14.
However, the transmitter 14 has been taken to a location beyond the
reception range of the receiver 12.
Notwithstanding the removal of the transmitter 14 to a place beyond the
reception range of the receiver 12, the transmitter 14 is made operational
by the aid of companion transducer or repeater units 16 and 18 connected
by a transmission line 20. The repeater unit 18 includes an infrared
emitter 22 located within the range of the receiver 12. The emitter 22
recreates the infrared radiation pattern of the remote control
transmitter.
For this purpose, the repeater unit 16 is located at the place where the
remote control transmitter 14 is to be operated. The unit 16 includes a
detector or sensor 24 and suitable amplifier and transducer components for
converting the radiation pattern to equivalent electrical signal form. The
electrical signal so created by the repeater unit 16 directly excites the
emitter 22, which converts the electrical signal into the same infrared
radiation pattern produced by the remote control transmitter 14. The
electrical or electromechanical device 10 accordingly responds as if the
remote control transmitter 14 were close by and in range.
The system thus described comprises three elements, companion transducer
units 16 and 18, and the transmission line 20. This system accommodates
any breed of remote control transmitter, whatever may be the form of its
intelligence--digitally coded pulse trains, discrete frequencies, or
otherwise. Moreover, the system accommodates a plurality of electrical or
electromechanical apparatus, each with its own breed of remote control
infrared transmitter and as depicted in phantom lines in FIG. 1.
In FIG. 2, the electrical or electromechanical apparatus controlled is, by
way of example, a cable converter 26 for a household television system.
The converter 26 is located in a general living area for operation of a
nearby television set or monitor 28 and for operation of a remotely
located television set or monitor 30. The repeater system comprising
companion units 16 and 18, and a transmission line are provided as in FIG.
1; however, the transmission line 20, in this instance, conveniently is
the very coaxial cable that normally interconnects the apparatus 26 to the
remotely located television set or monitor 30.
Of course, a separate dedicated conductor pair could be utilized instead of
the coaxial cable 20. If however, the coaxial cable 20 is used, some
isolation means must be provided to ensure that the infrared signals and
the television signals do not interfere. For this purpose, frequency
splitters 32 and 34 are provided at opposite ends of the coaxial cable 20.
The splitter 32 allows unrestricted passage of electrical signals in the
television frequency band, say 50 to 500 MHz from the cable 20 to the
television set or monitor 30, while blocking lower frequency signals
impressed on the cable 20 by the transducer unit 16. The splitter 32
allows unrestricted passage to the coaxial cable 20 of electrical signals
generated by the transducer unit 16. Well known remote control infrared
transmitters operate in bands below 10 MHz. Hence, appropriate isolation
is provided at the remote location. The frequency splitter 34 at the other
end operates in the same manner to achieve isolation.
The details of the repeater unit 16 are shown in FIG. 3 and the details of
the frequency splitters 32 and 34, as well as the repeater unit 18, are
shown in FIG. 4.
The repeater unit 16 shown in FIG. 3 includes a detector or sensor 24 which
may take a variety of configurations. A photo detector such as a photo
diode is shown which may be Part No. TIL 100 of Texas Instruments Company.
The photo diode produces a signal corresponding to the intelligence of the
infrared transmitter. For this purpose, a suitable load circuit is
provided. Two stages of amplification are provided by companion elements
of a quad amplifier, such as of National Semiconductor Company's Part No.
LM3900. A driver transistor cooperates to produce an output between output
terminals 42 and 44. Conventional components are labelled in FIG. 3.
Output terminals 42 and 44 connect with input terminals 46 and 48 (FIG. 4)
of the frequency splitter 32. As shown in FIG. 4, the divider or splitter
32 includes conventional capacitive and inductive circuit elements to
accomplish a frequency split in a known manner. The splitter 32 provides a
coaxial cable connector 50 of any suitable form for connection to the
television set or monitor at the remote location, and a jack or connector
52 for connection to the transmission line 20 which, in this case, is a
coaxial cable.
The divider or splitter 34 at the other end also includes conventional
capacitive and inductive circuit elements to accomplish the desired
frequency split. It includes a coaxial cable connector 54, and a jack or
connector 56 for cooperation with the television signal source, which in
the form of FIG. 2 is a cable converter 26.
The frequency splitter 34 provides output terminals 58 and 60 depicted as a
jack for cooperation with a plug 62 that places the emitter 22 directly
across the output terminals 58,60. The emitter may be incorporated in a
small case or attached to a bracket or clip for location adjacent the
receiver 12 of the companion apparatus. The emitter 22 may be any suitable
device that faithfully recreates infrared radiations in accordance with
its excitation. In the present instance, an infrared light emitting diode,
Part No. TIL 38 of Texas Instruments Company is quite suitable.
DETAILED DESCRIPTION OF SECOND EMBODIMENT
Not only can the system incorporating the transmission line 20 and infrared
repeater units 16 and 18 operate in conjunction with various infrared
remote control devices, but it can simultaneously accommodate hard-wired
remote control devices. In FIG. 5 there is depicted a telephone-type tone
code generator 70 packaged with the transducer unit 16. The output of the
tone code generator is applied directly to the output terminals 42 and 44
of the repeater unit 16 for transmission to the home station via the
frequency splitter 32, also packaged with the transducer unit 16 and
generator 70.
At the home station, a decoder 72 is packaged with the frequency splitter
34. The decoder 72 operates suitable switching devices, as by the aid of
flip flop 74 and relay coils 76. By means of the tone code generator 70
and decoder 72, single or multiple functions of various apparatus are
performed. For example, the decoder can determine operations of a cable
converter, a laser disk player, a video cassette recorder, etc., and can
direct their outputs to desired channels. The tone code generator 70 and
the companion decoder 72 operate well within the band defined by the
splitters 32 and 34.
The tone code generator 70 includes a conventional key pad 80 that operates
with a crystal controlled oscillator circuit utilizing, for example, a
Motorola integrated circuit part No. MC14410. The generator also includes
a suitable driver transistor 82, a crystal 84, and other components
arranged in a manner well known to those skilled in the art. The decoder
72 (FIG. 6) includes a demodulator or detector circuit 86 utilizing, for
example, integrated circuit part No. 292P of Silicon Systems, Inc.
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