United States Patent [19]
`Welles, II
`
`[11] Patent Number:
`[45] Date of Patent:
`
`4,623,887
`Nov. 18, 1986
`
`[73] Assignee:
`
`[54] RECONFIGURABLE REMOTE CONTROL
`Inventor: Kenneth B. Welles, II, Schenectady,
`[75]
`N.Y.
`General Electric Company,
`Schenectady, N.Y.
`[21] Appl. No.:
`610,377
`May 15, 1984
`[22] Filed:
`Int. G.' ........................ G08C i9/uu; H04N 5144
`[51j
`[52] U.S. Cl. .......................... 340/825.57; 340/825.69;
`340/825.72; 455/603; 358/194.1
`[58] Field of Search ...................... 340/825.57, 825.69,
`340/825.72, 825.34, 825.31; 358/194.1;
`455/601, 603, 608
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`4,200,862 4/1980 Campbell et al. .............. 340/310 A
`~,~f~,UO~ 6/1980 Litz et a1. ........................ 340/167 R
`4,398,193 8/1983 Kuniyoshi et al. .............. 358/194.1
`4,535,333 8/1985 Twardowski .................. 340/825.69
`Primary Examiner-Ulysses Weldon
`Assistant Examiner-Ralph E. Smith
`Attorney, Agent, or Firm-Marvin Snyder; James C.
`Davis, Jr.
`
`ABSTRACT
`[57]
`A reconfigurable remote control transmitter is disclosed
`that has the ability to learn, store and repeat the remote
`control codes from any other infrared transmitter. The
`reconfigurable remote control transmitter includes an
`infrared receiver, a microprocessor, nonvolatile and
`scratch pad random access memories, and an infrared
`transmitter. The microprocessor application is divided
`into four main categories: learning, storing, retransmit(cid:173)
`ting, and user interface. In the learning process, the
`reconfigurable remote control transmitter receives and
`decodes the transmissions from another remote control
`transmitter. The process is repeated at least twice for
`each key to make sure that it has been properly received
`and decoded. Once the data has been received and de(cid:173)
`coded, it is stored for later use. In order to do this, the
`received and decoded data is compressed so that it can
`fit into the nonvolatile memory. This process is re(cid:173)
`peated for each of the several remote control transmit(cid:173)
`ters that are to be replaced by the reconfigurable remote
`control transmitter. When the learning and storing op(cid:173)
`erations have been completed, the reconfigurable re(cid:173)
`mote control transmitter is ready to use.
`
`10 Claims, 13 Drawing Figures
`
`46
`
`48
`
`62
`
`12
`
`CQ Q:J L:2:=J
`G::J CQ CQ CD
`CQ~ c:::Q~
`c:::::::J
`CQ I
`
`ENTER
`78)
`
` 6/5/2014, EAST Version: 3.0.1.1
`
`

`

`u.s. Patent Nov. 18,1986
`Sheet 1 of9
`FIG.
`I
`MODULATION SCHEMES
`
`4,623,887
`
`0
`
`0
`
`I
`
`0
`
`a
`
`b
`
`C
`
`d
`
`e
`
`f
`
`h
`
`~-
`
`0
`I
`WItt M
`I
`I
`
`IA
`I
`
`0
`
`I
`
`I
`
`I
`
`I
`
`I
`
`I
`
`I
`
`I
`
`I
`
`I
`
`I
`
`~
`• 11M
`o 0
`0 _I,
`PNM II,.
`I I. M
`. ~
`0 • I
`
`0
`Ii
`I
`
`FIXED BIT TIME,
`FULL WIDTH BURST
`
`FIXED BIT TIME,
`BURST WIDTH MODULATED
`
`FIXED OFF TIME,
`BURST WIDTH MODULATED
`
`FIXED BIT TIME,
`SINGLE/DOUBLE BURST
`
`0
`
`0
`
`I
`~I I
`I
`
`I
`I
`
`I
`II
`I
`
`I
`
`0
`
`I
`
`I
`II
`i
`
`0
`
`0
`
`I
`
`~
`
`~
`
`i
`
`I
`~ ~
`
`0
`
`~
`
`FIXED OFF TIME,
`i SINGLE/DOUBLE BURST
`
`0
`
`J I
`
`~
`
`• I
`
`~
`
`~
`
`0
`
`FIXED BURST
`i TIME, OFF TIME
`MODULATED
`
`RANDOM
`
`ONE FREQUENCY
`FOR EACH KEY
`
`0
`
`I
`
`pOp
`
`o o
`
`I
`
`I
`
`pOD 00
`
`I
`
`I
`
`0
`
`SINGLE/OOUBLE PULSE,
`FIXED BIT TIME
`
` 6/5/2014, EAST Version: 3.0.1.1
`
`

`

`~
`til
`•
`""d
`
`~ a
`~ -00
`... -\C
`
`z
`
`00
`0'\
`
`tf.l g-
`~
`N
`~
`\C
`
`-
`
`I:···
`
`~ ...
`Q-\
`N
`o ... -- 00
`w
`o ... -- 00
`
`-.....J
`
`FIG. 2
`
`KEYBOARD ENCODING SCHEMES
`-I
`
`I --
`
`a P~~~s ~ L - I _ - - ' - -_ - - - - '
`
`PIREAMBLE
`
`KEY
`b PRESS
`
`KEY
`C PRESS
`
`-I
`
`I
`
`I
`c----_· I
`
`- - 1---
`
`--
`
`T -
`
`J
`
`SIMPLE
`
`REPEAT 3 TIMES,
`MORE FOR SOME KEYS
`- 1-
`- 1
`
`1- _ _ _ n~
`d P~~~S ~ I
`
`KEEP ALIVE CODE PULSES
`
`0
`0
`
`0
`D
`
`0
`D
`
`0
`0
`
` 6
`
`/5/2014, EAST Version: 3.0.1.1
`
`

`

`u.s. Patent Nov. 18,1986
`
`Sheet 3 of9
`
`4,623,887
`
`16
`'\
`
`.
`FIG. 3
`
`,-
`46 A'"
`
`1,11.'
`
`POWER
`
`...
`
`CHAN
`
`50~
`1
`r
`I
`J
`] (
`
`...
`
`VOL
`
`VOL
`~
`
`1
`
`/
`r
`---
`
`,---
`
`i
`1
`r
`1 I
`) [
`N MUTE
`48 /"
`CHAN
`::!E:
`C.52
`) ( VIDEO ) [BILINGUAL)
`( LCV
`( VCR/TV)
`67/ I--
`58--y
`~
`f-"L-
`l
`64~
`I
`REW ~ PAUSE }- ""C-
`66
`CABLE
`C
`
`fv; 54
`
`56
`~
`SE/
`EARN
`L
`WITCH
`S co VER
`-,
`60
`
`r-. 68
`
`-,
`/0
`
`~ 74
`
`\1/ ~~ ~I~ ~I~ ~~ \1/ r \1/ .& -s-
`/1\ /1\ /1\ /1\ 11\ 11\ 1'1'\ /1\ • ....
`...
`70~72~
`1- .-:r
`SOURCE J
`I (
`) I
`)
`~ 1- ..s-
`I-76
`)
`) [ +
`5 1 [
`) (
`I (
`I ILod~~l
`) ( -
`)
`,
`ENTER
`78./
`
`r DC'I'"
`)
`I ",-V J
`
`DC'I"'''Dn
`"'-vv,,..,
`
`1 r
`l
`J
`
`DI AV
`.- '-"'
`
`62 . ..., -
`
`H FF
`
`SOURCE:
`L
`FUNCTION: ERROR
`
`TV
`
`A
`
`VCR
`B
`
`AUX
`E
`
`0
`
`BATTERY
`
`PRESS MATCHING KEYS
`
`/2 ~
`
`FUNCTION
`
`ON IOFF
`
`{
`
`(
`
`(
`
`(
`
`I
`
`4
`
`7
`
`0
`
`2
`
`8
`
`) [
`
`) [
`
`3
`
`6
`
`9
`
`'\. /4
`
` 6/5/2014, EAST Version: 3.0.1.1
`
`

`

`u.s. Patent Nov. 18, 1986
`32 '\.. 35 PUSH-BUTTON KEYBOARD
`•
`
`Sheet4of9
`
`I
`I
`I
`I
`I
`
`~
`
`: SAMPLE PUSHBUTTON
`t
`
`4,623,887
`
`1\
`..L
`I
`-1-.
`I
`I
`....L
`I
`I
`
`AG.4e
`
`FIG.4a
`
`FIG.4b FIG.4c FIG.4d
`
`B+
`
`18
`
`22
`
`26
`
`30
`
`14
`
`RG.4a
`
` 6/5/2014, EAST Version: 3.0.1.1
`
`

`

`u.s. Patent Nov. 18,1986
`
`Sheet 5 of9
`24
`
`4,623,887
`
`I
`
`-'--'-,
`-'--,-_,-
`I \J
`
`I
`
`ALE
`
`MICRO
`COMPUTER
`
`cs
`Cl
`
`A9
`AS
`
`o~.,.
`n.;J1
`
`36 h
`
`B+
`
`LCD DRIVER
`
`4_4
`
`. FIG.4b
`
` 6/5/2014, EAST Version: 3.0.1.1
`
`

`

`u.s. Patent Nov. 18, 1986
`
`Sheet 6 of9
`
`4,623,887
`
`42\
`~OO 3
`~Dl 4
`~02 7
`~03 8
`~04 13
`~05 14
`~06 17
`07
`18
`20
`11 LE
`
`8+
`
`881T
`LATCH
`
`/
`
`2 AO/
`15 Al/
`6 A2/
`9 A3/
`12 A4/
`15 A5/
`16 A6/
`19 A7
`1
`10
`
`B+
`
`SOURCE:
`FUNCTION:
`
`L
`
`CABLE
`VCR
`TV
`ERROR ABC 0
`
`AUX
`E
`
`1~1~11~~II~~II~ILII~I(II~llll~I~II~I~1 ~
`1/1\11/1\11/1\11/1\11/1\1 111\1 1/1\1 1/1\1. ..
`BATTERY
`PRESS MATCHING KEYS
`F/G.4c
`
` 6/5/2014, EAST Version: 3.0.1.1
`
`

`

`u.s. Patent Nov. 18, 1986
`
`Sheet 7 of9
`
`4,623,887
`
`40"
`
`CMOS
`RAM
`
`"A7 1
`"A6 2
`r\.A5 3
`"A4 4
`"A3 5
`I\.A2 6
`r\.AI
`7
`f'\.AO 8
`A8 23
`/
`A9 22
`'/ AIO 19
`/
`B+~
`
`9 00/
`10 01/
`11 02/
`13 03/
`14 04/
`15 05/
`16 06/
`11 D7/
`20 CE
`21 WF..
`
`18 [§/ "
`~
`
`-
`
`+6V
`
`1>f-
`
`45 .......
`3VLi )----I>r-
`
`I\.A7
`~A6
`'A5
`"A4
`"A3
`"A2
`"AI
`AO
`A8
`A9
`AIO
`
`V
`V
`V
`
`FIG.4d
`
`"
`
`38",
`
`CMOS
`RAM
`
`/
`/
`/
`/
`/
`/
`/
`,/
`
`I--
`DO
`Dl
`02
`03
`04
`05
`06
`07
`CE
`WE
`OE
`
`'\
`
`"
`"
`
`r
`
` 6/5/2014, EAST Version: 3.0.1.1
`
`

`

`u.s. Patent Nov. 18, 1986
`
`Sheet 8 of9
`FIG. 50
`
`4,623,887
`
`BIT
`
`0
`
`PULSES
`TIME
`TIME
`BIN
`
`16
`.40
`
`A
`
`1.42
`.B
`
`36
`.92
`
`C
`
`.94
`D
`
`0
`
`15
`.39
`
`A
`
`38
`.95
`
`C
`
`.90
`D
`
`37
`.93
`
`C
`
`1.36
`B
`
`0
`
`17
`~2
`
`.96
`D
`
`200
`A END
`
`FIG. 5b
`B
`C
`D
`A
`14
`1.24
`33
`.82
`16
`1.42
`37
`.94
`18
`1.60
`1.06
`41
`BURST PAUSE· BURST PAUSE I
`
`BIN
`LOWER
`MIDDLE
`UPPER
`
`I TYPE
`
`FIG. 6
`
`KEY SEQUENCE
`lit
`2nd
`
`I
`
`2
`
`3
`
`4
`
`lit
`2nd
`3rd
`
`lit
`2nd
`3rd
`4th
`
`lit
`2nd
`
`A
`A
`
`A
`A
`A
`
`A
`A
`A
`A
`
`A
`A
`
`B
`B
`
`B
`B
`B
`
`B
`B
`B
`B
`
`B
`B
`
`C
`C
`
`·A
`A
`A
`
`C
`C
`C
`C
`
`C
`C
`
`D
`D
`
`B
`B
`B
`
`D
`D
`0
`D
`
`D
`D
`
`A
`A
`
`C
`C
`C
`
`C
`C
`C
`C
`
`A
`A
`
`B
`B
`
`D
`D
`D
`
`D
`D
`D
`0
`
`B
`B
`
`C
`C
`
`A
`E
`A
`
`A
`A
`A
`A
`
`A
`A
`
`D
`D
`
`A
`A
`
`C
`B
`:MOVED:
`B
`C
`
`D
`
`D
`
`C
`
`C
`
`:MOVED:
`B
`C
`C
`B
`B
`C
`
`B
`B
`B
`B
`
`B
`B
`
`F
`A
`A
`·A
`
`C
`C
`
` 6/5/2014, EAST Version: 3.0.1.1
`
`

`

`REMOVE REPEATS
`BYTES FIG. 7
`SEARCH FOR
`REPEAT SEQUENCE
`r---------------------------__ ~~~~----------------------~-
`fA BCD C 0 E F ABC 0 G H C 0 E F ABC 0 G H C 0 E F ABC 0 G H C 0
`
`IABIXI
`I A a C 01 X
`I A a CDC 0 I X
`I A a CDC 0 E F I
`
`. . .
`
`A alc OIC 01 x
`A alc 0 C 01 X
`A a IC 0 C 0 E F I X
`A a IC 0 C 0 E F A a I
`
`X
`
`x
`
`. .
`
`A a C OIC 01 x I
`A a C OIC 0 E FI x
`A a C OIC 0 E F A alc 0 x
`ABC OIC 0 E F ABC 01 X
`ABC olC 0 E F ABC 0 G HIC 0 E F ABC 0 G HIC 0 E F A a COG HIC 0 .~
`I':REAMBLfI s REPEATING PATTERN .1
`
`REDUCED FORMAT
`A a C OIC 0 E F ABC 0 G HI FIG.
`
`t.~
`
`~
`til
`•
`
`~ a ~ sa.
`
`z
`~
`""""'" 00
`'"
`""""'"
`\C
`00
`0'1
`
`til [
`\C g,
`
`\C
`
`~ ...
`0'\
`N w
`...
`00
`00
`-...J
`
`LOCATION 0
`COMPARISON
`1st
`2nd
`3rd
`4th
`LOCATION 2
`COMPARISON
`1st
`2nd
`3rd
`4th
`
`LOCATION 4
`COMPARISON
`1st
`2nd
`3rd
`4th
`5th
`
` 6
`
`/5/2014, EAST Version: 3.0.1.1
`
`

`

`1
`
`4,623,887
`
`2
`point of view of the consumer. A simpler, less expensive
`solution to the problem is needed.
`
`RECONFIGURABLE REMOTE CONTROL
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`The subject matter of this application is related to the
`subject matter of an application entitled "Programma(cid:173)
`ble Functions for Reconfigurable Remote Control"
`filed by Raymond G. Ehlers, Ser. No. 610,549 filed 10
`concurrently herewith and assigned to a common as(cid:173)
`signee with this application. The subject matter of that
`application is incorporated herein by reference.
`
`5
`
`FIELD OF THE INVENTION
`The present invention generally relates to remote
`control transmitters of the type used with various con(cid:173)
`sumer products such as television receivers and the like
`and, more particularly, to a reconfigurable remote con(cid:173)
`trol transmitter which may be programmed to emulate 20
`anyone of a plurality of individual transmitters.
`
`15
`
`35
`
`BACKGROUND OF THE INVENTION
`~,.1any new consumer electronic products, particu~
`larly video products, are available with hand held infra- 25
`red remote control transmitters. A consumer may have
`separate remote control transmitters for a television, a
`cable converter, video cassette recorder, and a video
`disc player, for example. In such a case, it is confusing
`to know which transmitter to pick up to control which 30
`prouct. Moreover, carrying around four different re(cid:173)
`mote control transmitters spoils the convenience of the
`remote control feature. It is therefore desirable to pro(cid:173)
`vide a single remote control transmitter for controlling
`each of the several products.
`A number of solutions have been proposed for this
`problem in the prior art. One example is disclosed in the
`patent to Litz et ai, U.S. Pat. No. 4,274,082. In the Litz
`et al system, an amplifier, a·tuner, a tape recorder, and 40
`a turntable are interconnected by a two-conductor ca(cid:173)
`ble. Each of these devices is controlled by a corre(cid:173)
`sponding microprocessor, and a hand held transmitter is
`used to transmit coded signals that control the operation
`of the inividual devices. The coded signals are received 45
`by a common receiver and first conversion circuit to
`provide voltage pulses on the two-wire cable. Addi(cid:173)
`tional conversion circuits are required for each micro(cid:173)
`processor in order to convert the voltage pulses on the
`two-wire cable to pulses which can be used by the mi- 50
`croprocessors.
`Another example is disclosed in U.S. Pat. No.
`4,200,862 to Campbell et al. The Campbell et al system
`includes a single receiver/transmitter unit which may
`be placed on a table, for example, and a hand held trans- 55
`mitter, but in this case, the receiver/transmitter unit
`injects digital pulses onto the house mains at times of
`zero crossing of the mains voltage. Various appliances
`are plugged into the house mains via slave units which
`are each responsive to an assigned digital address and a 60
`digital operation code to control its appliance.
`Common to both the Litz et al and Campbell et al
`systems is the use of a central receiver, an interconnect(cid:173)
`ing transmission line and the requirement of a separate
`controller device for each product or appliance. 65
`Clearly, this approach solves the basic problem of mul(cid:173)
`tiple transmitters for mUltiple products or appliances,
`but the solution is both complex and expensive from the
`
`SUMMARY OF THE INVENTION
`It is therefore an object of the present invention to
`provide a single remote control transmitter which can
`operate any product or appliance with a remote control
`feature without modification or interconnection of the
`individual products or appliances.
`It is another object of the invention to provide a
`simple an inexpensive control for a plurality of remotely
`controlled consumer products even though those
`proucts may be produced by different manufactures and
`respond to different transmission protocols.
`The objects of the invention are accomplished by
`providing a reconfigurable remote control transmitter
`that has the ability to learn, store and repeat the remote
`control codes from any other infrared transmitter. The
`reconfigurable remote control transmitter includes an
`infrared receiver, a microprocessor, nonvolatile and
`scratch pad random access memories, and an infrared
`transmitter. The microprocessor application is divided
`into four main categories: learning, storing; retransmit-
`ting, and user interface. In the learning process, the
`reconfigurable remote control transmitter receives and
`decodes the transmissions from another remote control
`transmitter for, say, a television receiver. The process is
`repeated at least twice for each key to make sure that it
`has been properly received and decoded. Once the data
`has been received and decoded, it must be stored for
`later use; however, in order to do this, the received and
`decoded data must be compressed so that it can fit into
`the nonvolatile memory. This process is repeated for
`each of the several remote control transmitters that are
`to be replaced by the reconfigurable remote control
`transmitter. When the learning and storing operations
`have been completed, the reconfigurable remote con(cid:173)
`trol transmitter is ready to use.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The foregoing and other objects, advantages and
`aspects of the invention will be better understood from
`the following detailed description of the invention with
`reference to the drawings, in which:
`FIGS. la to Ii are graphical representations of sev(cid:173)
`eral modulation schemes which are used in infrared
`remote control transmitters:
`FIGS. 2a to 2d are graphical representations of sev(cid:173)
`eral keyboard encoding schemes that may be used with
`the modulation schemes illustratted in FIGS. la to Ii;
`FIG. 3 is a plan view of the reconfigurable remote
`control transmitter according to a preferred embodi(cid:173)
`ment of the present invention;
`FIGS. 4a-4d, aligned from left to right, constitute a
`block diagram designated FIG. 4 of the reconfigurable
`remote control transmitter according to a preferred
`embodiment of the invention;
`FIGS. Sa and Sb are graphical and tabular representa(cid:173)
`tions of the data collection and initial data compression
`technique performed by the preferred embodiment
`shown in FIG. 4;
`FIG. 6 is a tabular representation of the correlation
`process performed during the learning procedure;
`FIG. 7 is a tabular representation of the process of
`removing repeats from the learned code in order to
`further compress the data for storing in the nonvolatile
`memory; and
`
` 6/5/2014, EAST Version: 3.0.1.1
`
`

`

`3
`FIG. 8 is a tabular representation of the compressed
`learned code.
`
`4,623,887
`
`4
`desired which causes the individual legends TV, VCR,
`CABLE, and AUX to be successively displayed in
`accordance with the succession of source key depres(cid:173)
`sions. When the legend for the desired source is dis-
`5 played, the user simply proceeds to operate the selected
`source. There is also provided a learning switch (not
`shown) which may be provided in a protected location
`on the side or bottom of the transmitter case since this
`switch is used only once (typically) for each transmitter
`which is to be emulated. This switch might be located,
`for example, behind a slidable or pivotal cover 67 in
`order to prevent younger members of the family from
`operating it. In the learning mode, the switch is moved
`to the learmng position and the transmitter which is to
`be emulated is placed so that its transmitter infrared
`light emitting diode (LED) is adjacent the photoelectric
`receiver in the reconfigurable remote control unit. The
`photoelectric receiver 14 might, for example, be located
`at the end opposite to the infrared LED transmitter 16
`in the reconfigurable remote control transmitter as
`shown in FIG. 3. The source is selected by pressing the
`source key 12 as described above, and when the legend
`for the desired source is displayed, the user presses the
`entire key 78. The user is then prompted in the liquid
`crystal display 10 to press a key on the reconfigurable
`remote control transmitter and a corresponding key on
`the transmitter to be emulated so that the transmitted
`code can be received and encoded. As will be explained
`in further detail, this prompt is repeated at least twice
`for each key in order to insure that the transmitted
`signal has been properly received and encoded.
`Turning now to FIG. 4, the receiver 14 for the recon-
`figurable remote control transmitter includes a photodi(cid:173)
`ode 18 connected by a differentiating capacitor 20 to the
`variable input of threshold amplifier 22. The output of
`this amplifier 22 is a series of pulses having a frequency
`equal to the frequency of the transmitted signal. The
`output of amplifier 22 is connected to an input of the
`microprocessor 24 and also to a detector diode 26. The
`output of the detector diode 26 is integrated by capaci(cid:173)
`tor 28 and supplied to the variable input of a second
`threshold amplifier 30. The output of this amplifier is
`the detected envelope of the transmitted signal and is
`supplied to another input of the microprocessor 24.
`Also supplied as inputs to the microprocessor 24 are the
`outputs of the push button keyboard 32 and the learn
`switch 34. The microprocessor 24 has its own internal
`clock which is controlled by a crystal 36. The micro(cid:173)
`processor 24 provides addresses for the nonvolatile
`random access memory 38 and the scratch pad memory
`40 to the address register 42 which comprises an 8-bit
`latch. The two memories are essentially the same except
`that the nonvolatile random access memory 38 is pro(cid:173)
`vided with a low voltage power supply 45, typically a
`lithium battery, in addition to being supplied from the
`main power supply in order to maintain the data stored
`in the memory even when the main battery supply is off
`or dead. The microprocessor 24 also provides the con(cid:173)
`trol signals to the LCD driver 46 which in turn controls
`the liquid crystal display 10. In addition, the micro(cid:173)
`processor provides the drive signals for the infrared
`transmitter 16. In order to minimize battery drain, the
`several integrated circuits shown in FIG. 4 are made
`with CMOS (complementary metal oxide semiconduc(cid:173)
`tor) technology. For example, the microprocessor may
`be an Intel 87C51 or a Mitsubishi 50741 microprocessor,
`and the memories may be Intel 2816 or Hitachi HM6116
`random access memories.
`
`25
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`In order to understand the learning process, the avail(cid:173)
`able infrared codes to be learned must first be under(cid:173)
`stood. This turns out to be a very wide range of differ(cid:173)
`ent codes. FIG. 1 illustrates several modulation
`schemes. FIGS. la through Ig are different types of 10
`gated carrier frequency. Typical carrier frequencies for
`infrared remote transmitters are 20 KHz to 45 KHz,
`with the maiority at 38 KHz and 40 KHz. The gating
`schemes illustrated include both fixed and variable bit
`periods, non-return to zero (NRZ), variable burst 15
`width, single/double burst modulation schemes, and a
`final catch-all category called random because there is
`no readily distinguishable pattern of ones and zeros. In
`addition to these schemes, there is also a transmitter
`which puts out a different continuous frequency (CW) 20
`for each key at approximately 300 Hz spacings as repre(cid:173)
`sented in FIG. Ih. Finally, several new types of trans(cid:173)
`mitters do not use a carrier frequency at all but, instead,
`send a stream of pulses where the data is encoded in the
`spacing between infrared pulses as shown in FIG. Ii.
`FIG. 1 shows the data modulation schemes, but most
`transmitters also have a higher level of data organiza(cid:173)
`tion, which may be called a keyboard encoding scheme.
`This causes data to be sent in different formats depend(cid:173)
`ing on the transmitter and the key pressed. FIG. 2 30
`shows several of these keyboard encoding schemes.
`FIG. 2b shows data that is sent once for each key press.
`FIG. 2c shows data that is repeated three times and then
`stopped for each key press. These schemes are used to
`conserve power and extend battery life. FIG. 2c also 35
`shows data that continues to repeat as long as the key is
`pressed. This is often used for continuous functions such
`as volume control or channel scanning. FIG. 2d shows
`a modification of the continuous repeat scheme shown
`in FIG. 2c where the initial key data is sent, followed by 40
`a series of "keep-alive" pulses as long as the key is
`pressed. This scheme is also used to conserve power and
`extend battery life. In addition to schemes 2b through
`2d, some remote control transmitters preceed all trans(cid:173)
`mitted key data witth some form or preamble data 45
`stream to get the receiver's attention. This is shown in
`FIG. 2a, but it will be understood that such preamble
`data stream can be used with each of the keyboard
`encoding schemes shown in FIG. 2.
`Reference is now made to FIG. 3 which shows in 50
`plan view the reconfigurable remote control transmitter
`according to a preferred embodiment of the invention.
`The first thing to be observed is that this unit is not
`much more complicated than a single transmitter for a
`single product. This is accomplished by the use of a 55
`combination of hard keys and soft keys and an liquid
`crystal display (LCD) about which more will be said
`latter. Suffice it to say for now that hard keys are those
`which have a predefined function and soft keys are
`those which have a programmable function. The recon- 60
`figurable remote control transmitter shown in FIG. 3 is
`capable of emulating up to four different transmitters
`, which are indicated in the liquid crystal display 10 adja(cid:173)
`cent the legend "SOURCE" as TV, VCR, CABLE,
`and AUX, the latter being for "auxiliary" which may be 65
`any fourth device such as, for example, a video disc
`player. The user selects the desired source by pressing
`the source key 12 each time a change in the source is
`
` 6/5/2014, EAST Version: 3.0.1.1
`
`

`

`4,623,887
`
`5
`The reconfigurable remote control in the learning
`process, must be able to receive, learn and repeat all of
`the schemes described with reference to FIGS. 1 and 2.
`In addition, in the learning process the reconfigurable
`remote control must read each code at least twice to 5
`make sure that it has been properly received and de(cid:173)
`coded. Small variations in the incoming code must be
`tolerated while large variations (errors) must be recog(cid:173)
`nized and rejected. The process, according to a proce(cid:173)
`dure entitled LEARN ONE KEY in the program for 10
`microcomputer 24, is illustrated with reference to
`FIGS. Sand 6. Referring to FIG. Sa first, the modula(cid:173)
`tion scheme represented by FIG. Ib is taken as exem(cid:173)
`plary. This modulation scheme uses a tixed bit time but
`the burst width is modulated. In other words, the time 15
`for a binary "1" is the same as the time for a binary "0"
`but, in the case illustrated, the number of pulses trans(cid:173)
`mitted for a "1" is more than for a "0". The time period
`for a binary bit is nominally 1.85 milliseconds, the num(cid:173)
`ber of pulses for a binary "I" is nominally 37, and the 20
`number of pulses for a binary "0" is'nominally 16. When
`the learn switch 34, shown in FIG. 4 is switched to the
`"learn" position, the liquid crystal display 10 flashes the
`letter "L" to constCL,tly remind the user that the recon(cid:173)
`figurable remote control transmitter is in the learn 25
`mode. The user is then prompted to press a key on the
`reconfigurable remote control transmitter and a corre(cid:173)
`sponding key on the transmitter to be emulated in order
`to transmit a signal to be received and encoded. The
`first step in the receiving and encoding process is to 30
`count the number of pulses in each burst and the time
`period of each pause between pulses. This pulse count
`and pause duration data completely defines the incom(cid:173)
`ing signal. From this data the frequency of the transmit(cid:173)
`ted signal is computed by dividing the largest number of 35
`pulses in a single burst by its corresponding time dura(cid:173)
`tion. For example, in FIG. Sa the largest number of
`pulses is 38 and its time period is 0.95 milliseconds,
`resulting in a 40 kilohertz transmitting frequency. The
`reason for using the largest number of pulses and its 40
`time period is to obtain the most accurate determination
`of the frequency of the transmitted signal. This initial
`raw data consists of 100 states, each state being defined
`as two I6-bit numbers (between 1 and 65,535). The first
`I6-bit number represents the number of infrared pulses 45
`in the pulse train. The second I6-bit number represents
`the time interval that the infrared pulse train was off.
`An additional I6-bit number represents the frequency of
`the infrared pulse train (typically from 30 KHz to 100
`KHz). This data requires about 3200 bits of data per key 50
`pressed.
`The first compression of this data is made by catego(cid:173)
`rizing the pulse bursts and pauses into "bins", each bin
`being two bytes with the most significant bit indicating
`whether the bin is a burst or a pause. As shown in FIG. 55
`Sa, four bins, identified as CATEGORIES in the pro(cid:173)
`gram for microcomputer 24 of FIG. 4, are established
`for the illustrated example according to a procedure of
`the program procedure entitled CONVERT IR DATA
`TO CATEGORIES. These are labeled A, B, C, and D 60
`with A and C being designated as bins for bursts and B
`and D being designated as bins for pauses. It will of
`course be understood that more or fewer bins may be
`required depending on the modulation scheme which is
`being learned. In order to categorize the pulse bursts 65
`and pauses into the several bins, a tolerance is estab(cid:173)
`lished so that all the bursts and pauses within a nominal
`range are appropriately categorized into one or another
`
`6
`of the bins. This is indicated in FIG. Sb which shows
`lower, middle and upper values of the number of pulses
`in a burst and the duration of a pause. Those bursts or
`pauses not falling into one of these bins would be as(cid:173)
`signed to another bin established for that burst or pause.
`By creating these bins, the initial raw data or about 3200
`bits is stored to 1600 bits per key and 16 bits per bin in
`the scratch pad memory 40 in FIG. 4. The user is then
`prompted in the liquid crystal display 10 to press the
`encoded key a second time and the process is repeated.
`Then correlation is performed on the encoded data for
`that key as illustrated by FIG. 6. Suppose that for key
`one, the two encoded data are the same as shown at the
`top of the figure. In this case, the key code sequence has
`been properly learned and can be further compressed
`for storage in the nonvolatile memory 38. On the other
`hand, assume that in the process of pressing key two for
`the second time, the user inadvertently moves the trans(cid:173)
`mitter to be emulated and the reconfigurable remote
`control transmitter with respect to one other ·so that the
`encoding for the second key press is an error. In this
`case, the user will be prompted on the liquid crystal
`display 10 to press the key a third time. If the third
`encoding matches the first as iHustrated in the figure 1
`then the key code sequence is considered to be properly
`learned and can be further compressed for storage in the
`nonvolatile memory. A third possiblity is illustrated in
`FIG. 6 and this is the case where the initial encoding is
`in error. Under these circumstances, no successive en(cid:173)
`coding would ever match the first. What the correlation
`algorithm does in this case is if the third encoding does
`not match the first, then the fourth is compared with the
`third and so on until a match of alternate encodings is
`obtained.
`When each key has been properly learned, the ini(cid:173)
`tially encoded data for each key must be further com(cid:173)
`pressed to such an extent that the data for all four re(cid:173)
`mote transmitters will fit into a 2K byte memory. This
`data compression must maintain all of the vital informa(cid:173)
`tion so that the infrared signal can be accurately recon(cid:173)
`structed during transmission. The first step is illustrated
`in FIG. 7 and as set out in a procedure entitled RE(cid:173)
`MOVE REPEATS in the program for microcomputer
`24 of FIG. 4, involves the removal of repeats from the
`key encoding. It will be recalled that some of the key(cid:173)
`board encoding schemes shown in FIGS. 2c and 2d
`involved repeated transmission patterns. As illustrated
`in FIG. 7, the first two bytes (each representing a differ(cid:173)
`ent bin) are compared with the second two bytes, and if
`there is no match, then the first four bytes are compared
`with the next four bytes. Again, if there is no match, the
`first six bytes are compared with the next six bytes and
`so on increasing in two byte intervals until a total of half
`of the stored bytes are being compared with the other
`half of the stored bytes. If no match is obtained, then the
`process is repeated from the start but omitting the first
`two bytes and then the first four bytes. In the case illus(cid:173)
`trated in the figure, a repeating pattern of ten bytes is
`found after an initial four byte preamble. The number
`and pattern of the repeats are then encoded in a reduced
`format, as shown in FIG. 8. This reduces data to be(cid:173)
`tween 6 and 60 states per key, 96 to 960 bits of data per
`key. Once this'has been accomplished, the encoding for
`all keys is examined in order to determine if there is a
`common preamble. If there is, this preamble is sepa(cid:173)
`rately encoded and stripped from the encoding of all
`keys according to a procedure entitled REMOVE
`PREAMBLES in the program for microcomputer 24 of
`
` 6/5/2014, EAST Version: 3.0.1.1
`
`

`

`7
`FIG. 4. This reduces data to (typically) 96 to 480 bits
`per key. Then the number of bins. is re~resented ?~ a
`Tint
`smaller number of bits than the eight bits compnslng
`Tint
`each byte. For the case illustrated in FIG. 5, for exam-
`Treble
`pie, the number of bits required !o ~epre~ent the four 5 ~::~le
`bits is only two. Typically, the 8-blt bin pOinter or num-
`ber is reduced to a 5-bit or less bin pointer depending on
`::!nce
`the number of bins required to encode the original data.
`Balance
`This typically reduces data to 48 to 240 bits per key: In
`Sharpness
`this way, data is reduced to a manageable storage Size, 10 Sharpness
`.
`11
`Homenet
`and all of the compression data is also retained to a ow
`A
`re-expansion of the data to its uncompresse~ format for
`B
`retransmission during emulation. More specifically, the
`compressed data co~prises the bin code, the position of
`the start of any repeating patterns, the length of the 15
`repeating pattern, the number of r~peats, and the ~f(~­
`quency of the transmission. If there IS a preamble, thiS IS
`stored separately to be generated for each key pressed.
`This compressed data is then stored in the nonvolatile
`memory 38 of FIG. 4.
`This completes the learning and storing pr~cesses
`which are common to all the keys on the transmitter to
`be emulated. Certain keys are common to most remote
`transmitters, and these keys are included on the recon- 25
`figurable remote control transmitter as shown in FIG.
`3. For example, the upper part of the transmitter in(cid:173)
`cludes a power key 46, a mute key 48, a channel up key
`50, a channel down key 52, a volume up key 54, and a
`volume down key 56. In addition, specific keys may be 30
`provided for a video cassette recorder such as a record
`key 58, a play key 60, a fast forward key 62, a rewind
`key 64, a stop key 66, and a pause or stop motion key 68.
`At the lower part of the transmitter there is the usual
`numerical keypad and enter key. Other keys shown may 35
`be assigned other predetermined functions. However,
`because the remote transmitters from different manufac(cid:173)
`turers vary widely, providing all the keys from even
`four different remote control transmitters on one unit
`would unduly complicate the reconfigurable remote 40
`control transmitter of the present invention and make
`operation confusing to the user. To avoid this, program(cid:173)
`mable or "soft" keys are provided which are controlled
`by means of the function key 70. These keys include an
`on/off key 72, an up key 74 and a down