RF Power amplifier with a modulating facility
AssigneeInternational Standard Electric Corporation
InventorAxel Fischer
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Abstract
An RF power amplifier with a pulse modulating facility is disclosed in which a pre-emphasized pulse modulating signal is derived from a plurality of amplitude values stored in a memory. The stored values are continuously changed by a control signal to give the output signal of the amplifier the desired shape. This compensates for nonlinearities and aging effects. The time required for the modulated carrier wave to pass through the amplifier need not be considered, because the envelope comparison between the amplifier output signal and the required modulating signal, which generates the control signal, is independent of the time of occurrence of the amplifier output signal.
Claims7
An RF power amplifier capable of being modulated by a pulse modulating signal having an arrangement to pre-emphasize said modulating signal so that an RF modulated output signal of said amplifier has a desired shape, said arrangement comprising:
- first means coupled to said amplifier to provide said modulating signal for amplitude modulating an RF carrier coupled to an input of said amplifier, said first means including a memory storing therein a predetermined plurality of amplitude values from which said modulating signal is derived;
- second means coupled to the output of said amplifier to rectify a portion of said amplifier output signal;
- and
- third means coupled to said second means and said memory to compare said rectified output signal with a reference pulse modulating signal to produce a control signal for said memory, said control signal having at least a first value when said rectified output signal is greater than said reference modulating signal and a second value when said rectified output signal is less than said reference modulating signal, said first and second values altering said stored amplitude values to provide a desired pre-emphasis for said modulating signal.
Dependencies are inferred from the claim text.