US2997535A - Signal powered television remote control system - Google Patents

Description

Aug. 22, 1961 s. T. BRADY ET AL SIGNAL POWERED TELEVISION REMOTE CONTROL SYSTEM Filed Nov. l2, 1958 2 Sheets-Sheet l IVM Aug. 22, 1961 s. T. BRADY ET AL 2,997,535

SIGNAL POWERED TELEVISION REMOTE CONTROL SYSTEM Filed NOV. l2, 1958 2 Sheets-Sheet 2 Llimited States Patent O 2,997,535 SIGNAL POWERED TELEVISION REMOTE CONTROL SYSTEM Sheldon T. Brady, North Hollywood, and Brian E.

Hooper, Sherman Oaks, Calif., assignors to Packard- Bell Electronics Corporation, Los Angeles, Calif., a corporation of California Filed Nov. 12, l1958, Ser. No. 773,478 12 Claims. (Cl. 178-5.8)

This invention relates to apparatus for providing a remote control over the operation of a television receiver. More particularly the application relates to apparatus for providing such a remote control without requiring that any battery or any other source of power be disposed in the remote control unit.

One of the stimulating forces in our American society is the attempt to enhance the convenience and ease of everyday life for the people who collectively comprise the American public. In all forms of our life, apparatus is constantly being developed and marketed to eliminate inconveniences which oder mental harassments against full enjoyment of an individuals pursuits at any instant. For example, in the television industry, remote control units are now being marketed which allow an individual to turn the television set on and olf from a remote position. The individual can also provide other controls over the operation of the television receiver such as to adjust the channel being viewed at any instant and to adjust the intensity of the sound. In this way, the individual can control the operation of the television receiver without having to get up from an easy chair or any other comfortable position.

Certain objectives should perhaps be met in order for remote control units to otter optimum convenience to people watching television. For example, the remote control units should be quite small so that they can be easily held Within the palm of an individuals hand. The remote control units should also be relatively light so as to minimize any inconvenience to the individuals holding the units. The remote control units should also be long-lived so that individuals can use the units for long periods of time without requiring any adjustment or replacement of parts. These objectives have not been entirely achieved in the electronic remote control units now in use. One reason has been the necessity of including in the remote control unit batteries or other sources of energy which are relatively heavy, large and short-lived.

This invention provides a system which overcomes the above disadvantages. Ihe system includes an oscillator which is disposed at the television receiver and which is constructed to produce signals at a particular frequency. These signals are transmitted toward the remote control unit, which operates to convert a portion of the transmitted energy into a direct voltage for powering a control stage such as an amplifier or modulator.

The modulator then operates to produce signals having a particular pattern dependent upon the particular control to be exerted over the operation of the television receiver. For example, modulating signals having a first pattern are produced to turn the television set on and modulating signals having a second pattern are produced to adjust the particular channel being viewed at any instant. The modulating signals are transmitted by the remote control unit to the television receiver, which is provided with certain stages to convert such signals into corresponding controls over the operation of the television receiver.

In the drawings: j

FIGURE 1 is a circuit diagram of an oscillator at a ICC television receiver for transmitting signals at a particular frequency to a remote control unit to obtain the operation of the remote control unit.

FIGURE 2 is a circuit diagram, partly in block form, of the electrical stages at the remote control unit for converting the signals transmitted by the circuit shown in FIGURE l into signals having individual frequencies dependent upon various controls such as buttons which are operated at the remote control unit.

FIGURE 3 is a circuit diagram in block form of electrical stages at the television receiver for responding to the signals from the remote control unit to provide controls over the operation of the television receiver in accordance with the frequency of the signals from the remote control unit.

FIGURE 4 is a circuit diagram, largely in block form, of a second embodiment which is operative to produce modulating signals having individual characteristics in accordance with the particular buttons depressed at any instant at the remote control unit.

FIGURE 5 is a circuit diagram, partly in block form, of electrical stages at the television receiver forI responding to the modulating signals from the remote control unit shown in FIGURE 4 to provide controls over the operation of the television receiver in accordance with the individual characteristics of the modulating signals.

FIGURE 6 is a perspective View of the remote control unit and particularly illustrates the disposition of various controls such as buttons in the casing of the unit; and

FIGURE 7 is `a front elevational view of a television receiver and illustrates one possibility for the relative positioning in the television receiver of the circuitry shown in FIGURES l and 3 and yfurther illustrates electrical shielding which may be disposed between the circuitry shown in FIGURES l and 3.

The electrical circuitry constituting this invention includes a continuously operating transmitter at a television receiver 11 (FIGURE 7) -for producing signals at a particular frequency such yas kilocycles per second. One possibility for the relative positioning of the transmitter in the television receiver is indicated in broken lines at 13 in FIGURE 7. The signals may be produced by an oscillator which may have any suitable electrical construction, one oscillator suitable for use being shown in FIGURE l. This oscillator includes a transistor 10 which may be of the PNP type and which may have an emitter, a base and a collector. The emitter of the transistor 10 is connected to the positive terminal of a suitable source 12 of direct voltage which may be obtained as by rectification from a step-down transformer in the television receiver. This source of direct voltage may be adapted to provide a suitable voltage such as 14 volts. This may be rectied lfrom l2 volts ArC. transformer in the television set. The negative terminal of the `source 12 is connected to an intermediate tap in a coil 14 such as the center tap in the coil. 'The coil 14 is constructed to provide a ytransmission or" oscillatory signals, as will be described in detail subsequently.

The end terminals of the coil :14 are connected to a capacitance 16. The capacitance 16 is provided with a value to be resonant with the coil 14 at a suitable fref quency such as approximately 100 kilocycles per second. The coil 14 and the capacitance 16 :are connected at one end to the collector of the transistor 10. A parallel combination of a capacitance 18 and a resistance 20 are disposed electrically between the base of the transistor 10 and the second terminals of the coil 14 and the capacitance 16.

The base of the transistor 10 is biased negatively by the battery 12 relative to the potential applied by the battery to the emitter of the transistor. This causes current to. ow through .the transistor 10 and through the resonant circuit formed by the coil 14 and the capacitance 16 to initiate the production of an oscillatory signal in the resonant circuit. The oscillatory signals are sustained by the introduction of feedback energy from the resonant circuit through the capacitance 18 and the resistance .20 tothe base of the transistor 10. The oscillatory signals are transmitted by the coil 14 to` the remote control unit `shown in VFIGURE 2.

The remo-te control unit shown in FIGURE 2 vincludes a circuit which is resonant'at the same frequency as the oscillatory signals produced by the circuit shown in FIG- URE l. This resonant Vcircuit may be :formed by a coil 22 and a variable capacitance 24 in parallel. When oscillatory signals are produced at la frequency of approximately lOO kilocycles per second, the capacitance 24 may be adjusted to a value of 300 micro-microfarads. The oscillatory signals produced by the coil 22 and the capacitance 24 in parallel are introduced through a coupling capacitance 26 to a current control member such as a semi-conductor. Specifically, the coil 22 and the capacitance 24 may be connected to the base of a PNP transistor 28, which may be a type 2N363.

The oscillatory signals from a first terminal of the resonant circuit formedby the coil 22 and the capacitance 24 are also introduced -to one terminal of a capacitance which may have a suitable value such as 100 micromicrofarads. A normally open switch 29 may be disposed electrically between the resonant circuit and the capacitance 30 to control the introduction of energy to the capacitance. A resistance 32 having a suitable value such as approximately 4.7 kilo-ohms is connected between the second terminal of the capacitance 30` and the second terminal of the resonant circuit formed by the coil 22 and the capacitance 24.

The second terminal of the capacitance 30 also has a common connect-ion with the cathode of a diode 36, the plate of which has electrical continuity with the first terminals of 'a resistance 38, the capacitance 40 and the resistance 42. The resistance 38, the capacitance `and the resistance 42 may be respectively provided with values in the order of 4.7 kilo-ohrns, .001 microfarads and 33 kilo-ohms.

Connections are made from the second terminals of the resistance 38 and the capacitance l40 to the emitter of the transistor 28. The second terminal of the resistance 42 is connected to the base of the transistor 28 and to one terminal of a resistance 44, which may be provided with `a value in the order of 22 kilo-ohms. The second terminal of the resistance `44 and the emitter of the transistor 28 extend electrically to the second terminal of the resonant circuit formed by the coil 22 and the capacitance 24.

A switch 48 is disposed electrically between the collector of the transistor 28 and a iirst terminal of a resonant circuit formed by a coil 50 and a capacitance 52 in parallel. The switch 4S may be normally open and may be closed upon the depression of a button `54 which extends through the casing 56 (FIGURE 6) of the remote control unit. The switch 29 is ganged to the switch 48 so as to become closed at the same time as the switch 48.

The second terminal of the resonant circuit formed by the coil 50 and the capacitance 52 is connected to the plate of the diode `36. The resonant circuit formed by the coil 50 and the capacitance 52 is tuned to a suitable harmonic frequency of the signals produced by the transmitter shown in FIGURE l. For example, the resonant circuit may be tuned to a frequency of approximately 300 kilocycles per second. The coil 50 in the resonant circuit is constructed to provide a transmission to these signals.

In like manner, a switch 60v is mechanically coupled to a button 62 which extends through the casing 56 of the remote control unit. The switch 60 is adapted to become closed upon a depression of the button 62 and is coupled to the switch 29 to produce a simultaneous closure of the switch 29. The switch 60 is disposed electrically between the collector of the transistor 28 and a resonant circuit forme-d by a coil 64 and a capacitance 66 in parallel. This resonant circuit is adapted to produce signals at a suitable harmonic frequency such as 400 kilocycle's per second. The coil 64 in the resonant circuit is constructed to provide a transmission of these signals. The second terminal of the resonant circuit formed by the coil v64 and the capacitance 66 is connected to the plate of the diode 36.

Other switches may be coupled to buttons in thecasing 56 so as to become closed upon a depression of their associated buttons. These switches may be ganged tothe switch 29 to produce a corresponding closure of the switch 29. The switches may be coupled to resonant circuits which are tuned to individual frequencies having a harmonic relationship to the signals produced by the oscillator shown in FIGURE l. vFor example, suitable individual frequencies for these additional resonant circuits may be 500 and 600* kilocycles per second.

The signals transmitted by the oscillator shown inFIG- URE l are received by the ycoil 22, which is resonant with the capacitance .24 at the same frequency as the received signals. The received `signals ordinarily have no effect on the circuitry shown in FIGURE 2 unless one of the buttons such as the buttons 54 and 62 in FIGURE 6 is depressed. Upon the depression of one of the buttons, the switch29 becomes closed so that the signals from the resonant circuit formed by the coilf22 and the capacitance 24 are able to pass through the .integrator formed bythe capacitance 30 and the resistance 32. This integrator operates in conjunction with the diode 36 to convert the alternating signals in the resonant circuit into a corresponding direct voltage of positive polarity. The resistance 38 and the capacitance 40 are also instrumental in facilitating the filtering action by reducing any ripples in theV direct voltage.

The positive voltage produced on the plate of the diode 36 upon a closure of the switch 29 causes a positive potential toV be applied to the base of the transistor 28 relative to the potential applied to the emitter of the transistor. The positive potential is applied Vto the base of the transistor 28 through the voltage-dividing network formed by the resistances A42and 44. This positive potential causes the transistor 28 to be normally biased against conduction. However, in the negative half cycles of the alternating voltage produced in the resonant circuit formed by the coil 22 and the capacitance 24, the potential on the base of the transistor 28 becomes negative relative to the potential on the emitter of the transistor so that the `transistor becomes conductive.

The transistor 28 serves as an amplifier-during the time that it is conductive. In addition, the transistor 28 provides a distortion in the characteristics of its output signals so that Vit in effect operates as a harmonic generator. The particular harmonic effective at any instant'is -dependent upon the depression ofthe different buttons which extend through the casing 56 in FIGURE 6. For example, when the button 54 is depressed to close the switch 48, the resonant circuit formed `by the coil 50 and the capacitance 52 is energized so that signals at an individual harmonic vfrequency such as 300 kilocycles per second are transmitted by the remote control unit. Similarly, signals at an .individual harmonic frequency such as 400 kilocycles per second are-transmitted by the coil 64 when the button 62. is depressed to produce a closure of the switch 60.

The harmonic signals produced by the coils such as the coils 50 and 64 are transmitted to the television receiver to control the operation of the television receiver. If desired, circuitry may be included in a manner similar to that disclosednand claimed in co-pending applicationrSerial No. 766,436 filed on October 10, 1958, by Brian E; Hooper, so that the signals can be received and transmitted on an omni-directional basis. This eliminates any necessity for the remote control unit to be pointed at the television receiver. Y

'Ihe signals at one harmonic frequency such as 300 kilocycles per second may be used to turn the television receiver on or ot. The transmitter depicted in FIGURE l is a separate unit and is not turned on and off with the receiver. A rst transmission of signals at this frequency may turn the set on, and a second transmission of signals at this frequency may turn the set oi. The signals at a second harmonic frequency such as 400 kilocycles per second may be used to advance in a forward direction the television channel being viewed at any instant. For example, the channel may be advanced from station 2 to station 3 upon the occurrence of signals at a harmonic frequency of 400 kilocycles per second. Similarly, signals at 500 kilocycles per second may be used to advance the channel selector in a reverse direction, and signals at 600 kilocycles per second may be used to adjust the volume of sound from the television receiver.

Circuitry is included at the television receiver to respond to the harmonic signals transmitted by the circuitry shown in FIGURE 2. Such circuitry at the television receiver may have different forms, one suitable form being shown in FIGURE 2. This circuitry is shown in block form since it can be quite similar to circuitry disclosed and claimed in co-pending application Serial No. 766,346 led on October l0, 1958 by Brian E. Hooper. The circuitry shown in FIGURE 3 is preferably shieded from the oscillator shown in FIGURE 1 so as not to be responsive to the oscillatory signals. The circuitry shown in FIGURE 3 may be disposed as indicated in broken lines at 69 in FIGURE 7 and may be shielded as at 71 and 73 from the circuitry shown in FIGURE l and indicated at 13 in FIGURE 7. The circuitry shown in FIGURE 3 includes various receiving stages such as stages 70 and 72 each responsive to the transmitted signals at a dilferent harmonic frequency. For example, the receiving stage 70 may be responsive to signals at 300 kilocycles per second and the receiving stage 72 may be responsive to signals at 400 kilocycles per second.

The signals received by the stage 70 are introduced through amplier stages 74 to a control stage 76. The control stage 76 is operative to convert the alternating signals into a corresponding direct voltage. The control stage 76 is simultaneously operative to introduce this direct voltage to an output member such as a solenoid or relay coil. The solenoid or relay coil is instrumental in controlling the operation of the television receiver in one particular function such as in turning the television receiver on and off. Similarly, the signals from the receiving stage 72 are introduced to amplifiers 78 and then to a control stage 80, which includes a solenoid or relay coil to obtain an advance of the station being viewed when the solenoid or relay coil is energized. The stages 70, 72, 74, 76, 78 and 80 are fully disclosed in co-pending application Serial No. 766,436 iiled on October 10, 1958 by Brian E. Hooper. The stages 70, 72, 74, 76, 78 and 80 may also be constructed in a manner fully described in Adler Patent No. 2,817,025 issued on December 17, 1957. In the embodiment of the remote control unit shown in FIGURE 4, the remote control unit operates to receive signals at 100 kilocycles per second from the transmitter shown in FIGURE 1. The remote control unit shown in FIGURE 4 is responsive to signals at this frequency by providing a tuned circuit 100 which corresponds to the tuned circuit formed in FIGURE 2 by the coil 22 and the capacitance 24. Circuitry indicated in block form at 102 in FIGURE 4 is included to produce a direct voltage from the oscillatory signals provided by `the tuned circuit 100. The circuitry indicated at 102 in FIGURE 4 may correspond to the circuitry shown` d in FIGURE 2 and including the capacitances 30 and 40, the resistances 32`and 38 and the iode 36.

A plurality of modulators are included in the circuitry shown in FIGURE 4 and are indicated at 104, 106 and- 108 in that figure. Each of the modulators 104, 106 and 108 may be provided with characteristics to produce signals at an individual frequency. For example, the modulator 104 may produce signals at a suitable frequency such as 5 kilocycles per second; the modulator 106 may produce signals at a suitable frequency such as 10 kilocycles per second; and the modulator 108 may produce signals at a suitable frequency such as l5 kilocycles per second.

Switches 110, 112 and 114 may be respectively disposed between the circuitry 102 controlling the production of the direct voltage and the modulators 104, 106 and 108. The switches 110, 112 and 114 may correspond to switches such as those designated at 48 and 60 in FIGURE 2. The switches 110, 112 and 114 are coupled to the dilferent buttons such as the buttons 54 and 62 in FIGURE 6 so as to become closed upon a depression of the associated button. In this way, the modulators 104, 106 and 108 can become activated only upon the depression of an associated one of the buttons.

As in the circuitry shown in FIGURE 2, the signals received by the resonant circuit activate the circuitry` 102 when one of the buttons such as the buttons S4 and 62 is depressed, This causes energy received from the transmitter shown in FIGURE 1 to be converted into a direct voltage. At the same time, one of the: switches 110, .112 and 114 becomes closed in accordance with the particular button depressed at any instant so as to activate the associated one of the modulators 104, 106 and 108. The activated modulator then introduces signals to a stage 118 which mixes the signals from the modulator with the signals from the tuned circuit 100. 'I'he stage 118 then transmits the modulated signals toward the television receiver.

It will be appreciated that each of the modulators such as the stages 104, 106 and 108 controls a different operation in the television receiver. For example, the signals from the modulator 104 may be instrumental in turning the television `receiver on or off. The signals from the modulator |106 may be instrumental in advancing the channel selector in a forward direction and the 4signals from the modulator 108 in advancing the channel selector in a reverse direction. Other modulators may be included to provide additional controls such as to adjust the intensity of the sound from the television receiver. g

FIGURE 5 illustrates in block form the circuitry at the television receiver for receiving the modulated signals from the remote control unit shown in FIGURE 4 and for providing corresponding adjustments in the operation of the television receiver in accordance with the intelligence represented by the modulating signals. The circuitry shown in FIGURE 5 includes a receiver `130 which is tuned to the carrier frequency of 100 kilocycles per second. t

The receiver is shielded from the oscillator shown in FIGURE 1 so as to be responsive only to the signals transmitted from the remote control unit shown in FIG- URE 4 without being responsive to the signals from the oscillator shown Iin FIGURE l. The signals passing through the receiver 1-30 are ampliiied in stages '132 and are subsequently introduced to a detector 134. The detector operates to remove the carrier signals at the frequency of 100 kilocycles per second so as to pass to subsequent stages only the signals from the modulators 104, 106 and 108.

The detected signals from the stage 134 are introduced to a plurality of different channels, each having a tuned circuit resonant at the frequency of the signals from a different one of the modulators. For example, tuned circuits 136, 138 and 4140 may be respectively resonant frequencies of approximately kilocycles per second, kilocycles per second and 15 kilocycles per second. The signals from the tuned circuits 136, 138 and 140i are respectively introduced to control stages |142, 144 and 146 corresponding to the control stages 76 and 86 in FIGURE 3. When energized, these control stages activate relay coils or solenoids to perform such operations `as turning the television receiver on and off, changingthe channel being viewed at any instant and adjusting the intensity of the sound. It is believed that these controls will be understood by a person skilled in the art from the disclosure in cor-pending application Serial No. 766,436 filed on October l0, 1958, by Brian E. Hooper.

What is claimed is:

l. In combination for providing a remote control over the operation of a television receiver in accordance with the operation of different controls at the remote position, means at the television receiver for producing-signals at a first particular frequency for transmission, means at the remote unit and responsive to the signals transmitted at the first particular frequency for converting into a direct voltage energy from the signals at the first particular frequency, means at the remote unit and responsive to the direct voltage and to the operation of the different controls for modulating the signals at the first particular frequency with signals having individual characteristics dependent upon the particular control being operated at any instant and for obtaining a transmission of such modulated signals, and means at the television receiver and responsive to the modulated signals transmitted from the remote unit for controlling the operation of the television receiver in accordance with the characteristics of the modulations.

2. In apparatus removed from a television receiver for controlling the operation of the receiver in accordance with the operation of different controls at a remote unit and in response to signals transmitted at a first particular frequency from the receiver, means responsive to signals transmitted at the first particular frequency for generating alternating signals, means responsive to the generated signals for producing a direct voltage, and means including a current control member biased by the direct voltage and responsive to the generated signals for producing signals having individual characteristics in accordance with the operation of the different controls and for providing for the transmission of such signals to the television receiver to control the operation of the receiver in accordance with the individual characteristics of the signals.

3. In combination for providing a remote control over the operation of a television receiver in accordance with the operation of different controls at the remote position, means at the television receiver for producing signals at a first particular frequency for transmission means including a current-control member at the remote unit and responsive to the signals at the rst particular frequency for generating harmonic signals of the first particular frequency, means coupled to the harmonic generator and operative upon the actuation of the controls at the remote unit for providing for the individual passage of the signals at the different harmonic frequencies in accordance with the particular controls actuated at any instant and for providing for the transmission of such signals, and means at the `television receiver and responsive to the signals at the different harmonic frequencies for controlling the operation of the television receiver in accordance with the particular harmonic frequency of the signals being received at any instant.

4. In combination for providing a remote control over the operation of a television receiver in accordance with the operation of different controls at the remote position, means at the television receiver for transmitting signals at a first particular frequency, means at the remote control unit and responsive to the signals transmitted at the first particular frequency for varying the characteristics of these signals in accordance with the particular controls to be operated at the television receiver at any instant and for transmitting the signals having the varied characteristics to the television receiver, and means` at the television receiver and responsive to the signals transmitted from the remote control unit to` obtain an adjustment in the operation of the television receiver in accordance With the varied characteristics of these transmitted signals.

5. In combination for providing a` remote control over the operation of a television received in accordance with the operation of different controls at the remote position,

means at the television receiver for producing signals atY a first particular frequency for transmission, means atv the remote control unit and responsive to the signals transmitted at the first particular frequency for converting energy from such signals into a direct voltage, a plurality of switches at the remote control unit, eachY switch being, coupled to a different one of the controls for activationy upon an operation of the associated control, means at the remote control unit and responsive to the generation, of the direct voltage and to the activation of the switches and to the signals at the first particular frequency for adjusting the characteristics of these signals in accordance with the particular switch activated atv any instant.

and for transmitting the signals with the adjusted characteristics, and means at the television receiver and responsive to the signals transmitted from the remote contijol unit for controlling the operation of the television receiver; in accordance with the individual characteristics of lthese transmitted signals.

6. In combination for providing a remote control over the operation of a television receiver in accordanceV with the operation of different controls at the remote position, means at the television receiver for transmitting signals at a first particular frequency, means at the remote unit and responsive to the signals transmittedV at the first particular frequency for converting energy represented Iby these signals into a direct voltage, means at` the remote unit and responsive to the direct voltage and to the signals transmitted at the first particular frequency and coupled to the controls in the remote unit forindividually varying the characteristics of these signals in accordance with the operation of the particular controls at any instant and for obtaining a transmission of thesel signals, and means at the television receiver and responsive to the signals transmitted from the remote control unit for varying the operation of the television receiver in accordance with the individual characteristics of the transmitted signals.

7. In combination for providing a remote control over the operation of a television receiver in accordance with the operation of `different controls at the remote position, means at the television receiver for producing signals at a first particular frequency for transmission, means at the remote unit and responsive to the signals transmitted at the first particular frequency for converting into a' direct voltage energy from the signals at the first particular frequency, a plurality of switches at the remote unit and each coupled to a different one of the controls a-tA the remote unit for actuation upon an operation of the associated control, an additional switch at the remote unit and coupled to the switches in the plurality for actuation upon an actuation of the switches in the plurality, means at the remote unit and including a currentcontrol member responsive to the signals at the first particular frequency upon an actuation of the additional switch for generating harmonic signals of the first particular frequency, means at the remote unit and responsive to the signals from the harmonic generator and coupled to the different switches in the plurality for providing for the passage of harmonic signals at individual frequencies in accordance with the actuation of the different switches in the plurality and for the transmission of such passed harmonic signals, and means at the television receiver and responsive to the transmitted harmonic signals for controlling the operation of the television receiver in accordance with the particular frequencies of the harmonic signals transmitted at any instant.

8. In combination for providing a remote control over the operation of a television receiver in accordance with the operation of different controls at the remote position, means at the television receiver for providing a transmission of signals at a particular frequency, means at the remote position and responsive to the transmitted signals and coupled to the diiferent controls at the remote position for modulating the transmitted signals with signals having individual characteristics dependent upon the actuation of the different controls and for providing for the transmission of such modulated signals to the television receiver, means at the television receiver and responsive to the signals transmitted to the television receiver for demodulating such transmitted signals, and means at the television receiver and responsive to the demodulated signals to control the operation of the television receiver in accordance with the characteristics of such transmitted signals.

9. In combination for providing a remote control over the operation of a television receiver in accordance with the operation of different controls at the remote position, means at the television receiver for providing a transmission of signals at a particular frequency, means at the remote unit and responsive to the signals transmitted at the rst particular frequency for converting energy from such signals into a direct voltage, means yat the remote unit and responsive to the direct voltage and to the signals transmitted at the first particular frequency and to the operation of the different controls for modulating the signals at the tirst particular frequency with second signals having a frequency dependent upon the particular control actuated at any instant and for providing for the transmission of such modulated signals, means at the television receiver and responsive to the signals transmitted from the remote unit to demodulate the signals at the first particular frequency for a passage of only the modulating signals, and means at the television receiver and coupled to the demodulating means for controlling the operation of the receiver in accordance with the frequency of the modulating signals.

10. In apparatus removed from a ltelevision receiver for controlling the operation of the receiver in accordance with the operation of different controls at a remote unit and in response to signals transmitted at a first particular frequency from the receiver, means responsive to the signals transmitted at the first particular frequency for converting energy from these signals into a direct voltage, a plurality of switches each coupled to a dilerent one of the controls for actuation upon an operation of the associated control, and means responsive to the direct voltage and to the actuation of the switches for producing signals having individual characteristics dependent upon the particular controls operated at any instant and for providing for the transmission of such signals to control the operation of the receiver in accordance with the individual characteristics of the signals.

1l. In apparatus removed from a television receiver for controlling the operation of the receiver in accordance with the operation of different controls at a remote unit and in response to signals transmitted at a first particular frequency from the receiver, means responsive to the signals transmitted at the iirst particular frequency for converting energy from these signals into a direct voltage, a plurality of switches coupled to the different controls for actuation in accordance with the operation of the controls, means responsive to the signals at the first particular frequency and responsive to the actuation of the controls for converting energy from the signals into a supply potential, and means including a current-control member responsive to the supply potential and to the signals at the iirst particular frequency for converting these signals into harmonics having at any instant a particular frequency dependent upon the particular controls actuated at that instant and for providing for the transmission of such harmonics to control the operation of the receiver in accordance with the frequency of such harmonics.

12. In combination for providing a remote control over the operation of a television receiver in accordance with the operation of different controls at the remote position, means at the television receiver for continuously producing signals at a rst particular frequency for short range transmission, means including tuned electrical circuitry at the remote unit and responsive to the signals transmitted at the rst particular frequency for developing biasing potentials from the transmitted signals at the first particular frequency when any one of the different controls at the remote position is operated, a plurality of switches at the remote unit and each mechanically coupled to the different one of the controls at the remote position for actuation upon the operation of the associated control, an additional switch at the remote position coupled to all of said plurality of switches for actuation upon the operation of any one of the switches in the plurality of switches to enable said tuned electrical circuitry to develop the biasing potentials, means including a transistor coupled to said tuned electrical circuitry and to said plurality of switches for receiving the biasing potentials developed by said tuned electrical circuitry and for selectively generating harmonic signals of the first particular frequency in accordance with the operation of said plurality of switches, means including a plurality of tuned circuits at the control position and individually associated with the switches in said plurality of switches for providing a tuned feedback connection across said transistor to cause said transistor to oscillate at a particular harmonic frequency of the tdrst particular frequency in accordance with the frequency of said tuned circuit, said tuned circuit also transmitting the particular harmonic frequency, and means lat the television receiver and responsive to the transmitted harmonic frequency for controlling the operation of the television receiver in accordance with the particular frequency of the .transmitted harmonic frequency.

References Cited inthe tile of this patent UNITED STATES PATENTS Pankove Jan.. 8, 1957 OTHER REFERENCES

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