Pulse modulator

Claim 2

A pulse modulator comprising an input signal source, means for establishing a first voltage pedestal, a common pull-up resistor having one end connected to a power source, a driver connected between said voltage pedestal means and the other end of said common pull-up resistor and responsive to said input signal, clamp means connected to said pedestal means, an amplifier having four terminals and including components having a breakdown voltage value less than the potential of the power source, said amplifier having a first terminal connected to the power source, a second terminal connected to said other end of said common pull-up resistor and comprising the input terminal, a third terminal connected to said clamp means for providing internal protection to said amplifier, and a fourth terminal comprising an output terminal for providing an output signal having a potential approximately equal to the potential of the power source.

Claim 3

The apparatus as described in claim 1 wherein said amplifier comprises a pair of transistors of a first polarity connected as a Darlington amplifier, wherein the collectors of said pair of transistors comprise said first terminal and the base of one of said pair of transistors comprises said second terminal, A third transistor of a second polarity having its emitter connected to the emitter of another of said pair of transistors, wherein the base of said third transistor comprises said third terminal and the collector of said transistor comprises said fourth terminal.

Claim 4

The apparatus of claim 1 including a current sensor responsive to the current at said first terminal of said amplifier, a current limiter amplifier responsive to said current sensor for varying the potential of said other end of said common pull-up resistor whereby the current at said fourth terminal of said amplifier is limited.

Claim 5

The apparatus as claimed in claim 3 wherein said current sensor comprises a potentiometer disposed between said first terminal and the power source, a transistor of one polarity having its emitter connected to one side of said potentiometer, its base connected to the variable element of said potentiometer and its collector connected to said current limiter amplifier, and wherein said current limiter amplifier comprises a transistor of another polarity having its base connected to said collector of said current sensor, its emitter connected to said pedestal means, and its collector connected to said other end of said pull-up resistor.

Claim 6

The apparatus of claim 1 including prebias circuitry comprising a second means for establishing voltage pedestal, further clamp means disposed between said second voltage pedestal means and said fourth terminal of said amplifier whereby the potential of said voltage pedestal means and the power source may be increased by an amount equal to the potential of said second voltage pedestal means.

Claim 7

The apparatus of claim 1 comprising a first stage and including a second stage, said second stage comprising a driver having input and output connections with its input connected across said voltage pedestal means in said first stage and the power source, a buffer disposed between the power source and one of said input connections of said driver, means for establishing a voltage pedestal connected to one of said driver outputs, a first clamp means connected to said voltage pedestal means, a second clamp means disposed between said first stage and said second stage for isolating said first stage from said second stage in the absence of an input signal, an amplifier having four terminals and including components having a breakdown voltage value of approximately one-fourth of the potential of the power source and said amplifier having a first terminal connected to said fourth terminal of said amplifier in said first stage, a second terminal connected to another of said driver outputs, a third terminal connected to said first clamp means, and a fourth terminal comprising an output terminal for providing an output signal having a potential approximately equal to the potential of the power source.

Claim 8

The apparatus as described in claim 6 wherein said amplifier of said second stage comprises a pair of transistors of a first polarity connected as a Darlington amplifier wherein the collectors of said pair of transistors comprise said first terminal of said second stage and the base of one of said pair of transistors comprises said second terminal of said second stage, a third transistor of a second polarity having its emitter connected to the emitter of another of said pair of transistors, wherein the base of said third transistor comprises said third terminal of said second stage and the collector of said transistor comprises said fourth terminal of said second stage.

Claim 9

The apparatus described in claim 6 wherein said driver of said second stage comprises a transformer having a 1 to 3 step up ratio, and said buffer comprises a transistor having its base connected to said other end of said pull-up resistor, its emitter connected to said one input connection of said transformer, and its collector connected to the power source. 9. The apparatus described in claim 6 wherein said second clamp comprises a three leg, two resistor voltage divider network having its junction point connected to said first terminal of said instant stage amplifier, one of said legs connected to said voltage pedestal means of said first stage and another of said legs connected to said voltage pedestal means of said second stage.

Claim 10

the apparatus of claim 6 including prebias circuitry comprising a third means for establishing a voltage pedestal, a third clamp means disposed between said third voltage pedestal means and said fourth terminal of said second stage, whereby the potential of said voltage pedestal means of said first stage, the potential of said voltage pedestal means of second stage and the potential of the power source may be increased by an amount equal to the potential of said third voltage pedestal means.

Claim 11

The apparatus of claim 1 comprising an initial stage and including a plurality of succeeding stages, each said succeeding stage comprising a driver having input and output connections with its input connected across the voltage pedestal means of a preceding stage and the power source, a means for establishing a voltage pedestal connected to one of said driver outputs, a first clamp means connected to said voltage pedestal means in the instant stage, a second clamp means disposing between the preceding stage and said instant stage for isolating said preceding stage from said instant stage in the absence of an input signal, an amplifier having four terminals and including components having a breakdown voltage of approximately one-half of the potential of the power source divided by the number of stages, said amplifier having a first terminal connected to the output of said preceding stage, a second terminal connected to another of said driver outputs, a third terminal connected to said first clamp means, and a fourth terminal comprising an output terminal for providing an output signal having a potential approximately equal to the potential of the power source.