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AssigneeEricsson Inc.
InventorsDavid R. Pehlke, Aristotele Hadjichristos, William O. Camp, Jr.
Estimating the term…
An amplitude modulation circuit (modulator) provides modulated supply current, possibly in combination with modulated supply voltage, to a radio frequency (RF) power amplifier (PA), and includes a detection circuit responsive to changes in the ratio of that voltage to the modulated supply current, described herein as its AM modulation impedance. Such impedance (resistance) changes commonly arise from changing coupling characteristics at the RF antenna assembly driven by the PA. A gain control circuit may be associated with the detection circuit, and made responsive thereto, thus allowing adjustment of modulation gain control responsive to changes in PA AM modulation impedance. In one embodiment, this arrangement permits the modulator to hold a fixed modulation gain over changing PA AM modulation impedance, while in other embodiments, modulation gain varies in response to PA impedance changes to avoid signal clipping. Such clipping might otherwise occur where current modulation values in combination with increased PA resistance would result in PA voltages exceeding the supply voltage of the PA.
A current modulator to supply a modulated supply current to a power amplifier responsive to an amplitude modulation signal, the current modulator comprising:
In a current modulator supplying a modulated current to a power amplifier, a method of inferentially sensing power amplifier (PA) AM modulation impedance in a current modulator where a power amplifier is supplied with a modulated supply current, the method comprising:
A current modulator to supply a modulated supply current to a power amplifier responsive to an amplitude modulation signal, the current modulator comprising:
Dependencies are inferred from the claim text.