Integral rf modamp

Claim 2

A modamp comprising: at least a first amplifier for amplifying an RF signal; a power amplifier including a power transistor for further amplifying said RF signal, the further amplified RF signal comprising an output signal; means for sensing the modulation on said output signal; means comparing the sensed modulation with an input signal for generating a first error signal; means responsive to said first error signal for controlling the current in said power transistor; means for generating a second error signal in accordance with the voltage at said power transistor; and, means responsive to said second error signal for controlling the drive of said first amplifier whereby the voltage at Said power transistor is maintained constant.

Claim 3

The modamp of claim 1 wherein said power transistor includes a first control electrode connected to receive the output from said first amplifier and additionally includes a second control electrode connected to said means for controlling current, the voltage at said second control electrode being maintained constant by said second error signal.

Claim 4

The modamp of claim 1 wherein said means for sensing comprises: first unilateral current means connected to receive said output signal; and, second unilateral current means connected to receive said output signal delayed by 90*.

Claim 5

The modamp of claim 3 wherein said first and second unilateral current means comprises first and second diodes and means for delaying said output signal by 90*.

Claim 6

A modamp comprising: a source of RF signals to be modulated and amplified; a preamplifier including a first transistor having at least an input electrode connected to receive said RF signals and an output electrode; a driver amplifier including a second transistor having at least an input electrode and an output electrode; means for connecting said first transistor output electrode to said second transistor input electrode; a power amplifier including a third transistor having at least an input electrode, an output electrode and a third electrode; means for connecting said second transistor output electrode to said third transistor input electrode; means connected to said third transistor output electrode for sampling the modulation content of the signal thereon; a source of a modulation signal; comparator means responsive to said modulation signal and the sampled signal for generating a first error signal; means responsive to said first error signal for controlling the current flow in said third electrode; and, feedback means from said third transistor for maintaining the voltage at said third electrode constant.

Claim 7

A modamp comprising: a source of RF signals to be modulated and amplified; a preamplifier including a first transistor having at least an input electrode connected to receive said RF signals and an output electrode; a driver amplifier including a second transistor having at least an input electrode and an output electrode; means for connecting said first transistor output electrode to said second transistor input electrode; a power amplifier including a third transistor having at least an input electrode, an output electrode and a third electrode; means for connecting said second transistor output electrode to said third transistor input electrode; means connected to said third transistor output electrode for sampling the modulation content of the signal thereon; a source of a modulation signal; comparator means responsive to said modulation signal and the sampled signal for generating a first error signal; means responsive to said first error signal for controlling the current flow in said third electrode; and, feedback means from said third transistor for maintaining the voltage at said third electrode constant.

Claim 8

The modamp of claim 5 wherein said feedback means comprises: means responsive to the voltage at said third electrode for generating a second error signal; and, means responsive to said second error signal for varying the drive of at least one of said preamplifiers and said driver amplifiers.

Claim 9

The modamp of claim 6 wherein said means for varying the drive comprises means responsive to said second error signal for varying the DC bias at the input electrode of at least one of said first and second transistors.

Claim 10

The modamp of claim 5 wherein said means for sampling comprises: at least one detector for sampling the signal on said third transistor output electrode; and, filter means for substantially removing the RF component from the signal sampled.

Claim 11

The modamp of claim 8 wherein said filter means includes means for attenuating the signal sampled.

Claim 12

The modamp of claim 5 wherein said means for sampling comprises: a first detector means having a first end connected to said third transistor output electrode and a second end; a second detector means having a first end and a second end, the first and second detector means second ends being connected together; and, signal delay means for connecting said first detector means first end to said second detector means first end.