Split cross fader for the control of theatre lighting

Claim 3

The method of claim 1 wherein said control unit is a dimmer such as dimmers used in stage lighting, said method permitting operation as a scene master control, a cross fader control and a pile-on control for two scenes and said first and second inputs are first and second scenes respectively.

Claim 4

The method of claim 1 wherein said multiplying is carried out by generating first and second pulse trains having pulses thereon of equal amplitude and multiplying said pulse trains by the values C 1X and C 1Y , respectively.

Claim 5

The method of claim 1 wherein said multiplying of said first and second pulse trains is done by amplitude modulating said pulse trains.

Claim 6

Apparatus for developing voltage control signals to be provided to a control unit which is to be controlled in response to either of two control inputs with fading between inputs possible, comprising: a. means for generating a periodic waveform voltage having an upper peak reference and lower peak reference value; b. means for generating a first analog voltage proportional to a value P X corresponding to a first fader control position; c. means for generating a second analog voltage inversely proportional to a value P Y corresponding to a second fader control position; d. first means for comparing said periodic waveform with said first analog voltage and for providing an output at one level when said first analog voltage is greater than the voltage of said waveform and at another level when said waveform voltage is greater than said first analog voltage to thereby develop a first pulse train having a duty cycle variable between 0 and 100 percent; e. second means for comparing said periodic voltage with said second analog voltage and for providing an output at said one level when said waveform voltage is greater than said second analog voltage and at said other level when said waveform voltage is less than said second analog voltage to provide a second pulse train, the timing of said first and second pulse trains being such so that when the sum of the duty cycles of the pulses on said first and second pulse trains is less than 100 percent, the pulses do not overlap in the time domain; f. first storage means for storing a value C 1X proportional to a first preset, said first storage means having said first pulse train as an input and responsive to provide pulses having the same duty cycle as said input pulse train and having an amplitude proportional to said value C 1X ; g. second storage means for storing a value C 1Y proportional to a second output preset, said second voltage storage means having said second pulse train as an input and responsive to provide output pulses having the same duty cycle and having an amplitude proportional to said value C 1Y ; and h. means for combining the outputs of said first and second storage means so as to provide an output equal to the greater instantaneous value of said two inputs, said output being the control voltage of said circuit.

Claim 7

Apparatus for developing voltage control signals to be provided to a control unit which is to be controlled in response to either of two control inputs with fading between inputs possible, comprising: a. means for generating a periodic waveform voltage having an upper peak reference and lower peak reference value; b. means for generating a first analog voltage proportional to a value P X corresponding to a first fader control position; c. means for generating a second analog voltage inversely proportional to a value P Y corresponding to a second fader control position; d. first means for comparing said periodic waveform with said first analog voltage and for providing an output at one level when said first analog voltage is greater than the voltage of said waveform and at another level when said waveform voltage is greater than said first analog voltage to thereby develop a first pulse train having a duty cycle variable between 0 and 100 percent; e. second means for comparing said periodic voltage with said second analog voltage and for providing an output at said one level when said waveform voltage is greater than said second analog voltage and at said other level when said waveform voltage is less than said second analog voltage to provide a second pulse train, the timing of said first and second pulse trains being such so that when the sum of the duty cycles of the pulses on said first and second pulse trains is less than 100 percent, the pulses do not overlap in the time domain; f. first storage means for storing a value C 1X proportional to a first preset, said first storage means having said first pulse train as an input and responsive to provide pulses having the same duty cycle as said input pulse train and having an amplitude proportional to said value C 1X ; g. second storage means for storing a value C 1Y proportional to a second output preset, said second voltage storage means having said second pulse train as an input and responsive to provide output pulses having the same duty cycle and having an amplitude proportional to said value C 1Y ; and h. means for combining the outputs of said first and second storage means so as to provide an output equal to the greater instantaneous value of said two inputs, said output being the control voltage of said circuit.

Claim 8

The apparatus according to claim 5 wherein said control unit is a dimmer such as dimmers used in stage lighting, said method permitting operation as a scene master control, a cross fader control and a pile-on control for two scenes and said first and second inputs are first and second scenes respectively.

Claim 9

The apparatus according to claim 6 wherein said means for providing first and second analog voltages comprise first and second potentiometers referenced to said higher and lower peak references.

Claim 10

The apparatus according to claim 7 wherein the setting of the first potentiometer providing an output value proportional to P X is such that for a 100 percent P X value, the wiper of said potentiometer is at the end coupled to said upper peak reference and for a 100 percent P Y value, the wiper of said second potentiometer is at the end of said potentiometer coupled to the lower peak reference.

Claim 11

The apparatus according to claim 8 wherein said means for comparing comprise first and second comparators, one having its inverting input coupled to said waveform generator and the other its non-inverting input thereto, the second inputs of said comparators being coupled respectively to the wipers of said first and second potentiometers.

Claim 12

The apparatus according to claim 9 wherein said first and second storage means comprise first and second potentiometers coupled between the output of said comparing means and ground, said potentiometers having their wipers preset to correspond to said values C 1X and C 1Y , respectively whereby the voltage output of said comparators will be multiplied by the fractional setting of said potentiometers.

Claim 13

The apparatus according to claim 10 wherein said means for combining comprises a diode network.

Claim 14

The apparatus according to claim 11 wherein said diode network comprises first and second diodes having their anodes coupled respectively to the wipers of said first and second potentiometers and their cathodes coupled together to provide the final circuit output.

Claim 15

The apparatus according to claim 11 and further including a filter coupled between said diode network and the final circuit output.

Claim 16

The apparatus according to claim 6 and further including pairs of voltage storage means C 2X , C 2Y . . . C NX , C NY , each of said additional storage means being separately preset and having their inputs coupled to the outputs of said first and second comparator means.

Claim 17

The apparatus according to claim 14 wherein each of said voltage storage means comprises a potentiometer coupled between a comparator means output and ground.

Claim 18

The apparatus according to claim 6 and further including a switching amplifier between each of said comparing means and each of said voltage storage means.

Claim 19

The apparatus according to claim 16 wherein said switching amplifier comprises a transistor switch.

Claim 20

The apparatus according to claim 17 wherein each of said transistors is supplied with a predetermined voltage level from a voltage supply.

Claim 21

The apparatus according to claim 18 wherein said supply is adjustable.

Claim 22

The apparatus according to claim 19 and further including a blackout switch in the line coupling said switching amplifiers and said voltage supply.

Claim 23

The apparatus according to claim 20 and further including a potentiometer in the line coupling said supply and said transistors.

Claim 24

The apparatus according to claim 6 wherein said voltage storage means are coupled to said comparing means outputs through switches, whereby different sets of said voltage storage means may be coupled to different ones of said comparing means outputs.

Claim 25

The apparatus according to claim 22 and further including a diode coupling said potentiometers to ground to thereby compensate for the voltage drop through the diodes in said combining means.

Claim 26

The apparatus according to claim 6 wherein said voltage storage means are coupled to said comparing means through individual switches and further including isolation diodes between each comparator and storage means whereby a single storage means can simultaneously be coupled to both of said comparing means.