| CPC H04W 52/52 (2013.01) [H04B 1/0007 (2013.01)] | 20 Claims |
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1. A radio frequency generator, comprising:
a radio frequency (RF) circuit comprising an RF source providing an RF signal of a first frequency derived from a first clock and a signal modulator generating a pulsed radio frequency (RF) signal having an On period where the RF signal is provided at an output terminal and an Off period where no RF signal is provided; and
an automatic level control circuit configured to sample the pulsed RF signal at the output terminal and to generate a control signal to modulate the RF signal at the radio frequency circuit, the automatic level control circuit comprising:
first and second analog-to-digital converters configured to sample respective forward RF signal and reflected RF signal at the output terminal at a sampling frequency and to generate digital samples of the respective forward and reflected RF signals, the sampling frequency being derived from a sampling clock synchronized to the first clock and being less than the first frequency of the RF signal;
a gated accumulation circuit configured to receive respective digital samples of the forward and reflected RF signals and selecting digital samples based on a sample index identifying the digital samples;
a digital signal processor configured to process the selected digital samples to generate a measured signal level value;
an error processor configured to compare the measured signal level value to a reference signal level to generate an error signal indicative of a difference thereof; and
a modulator controller configured to generate the control signal in response to the error signal and a pulse modulation signal, the pulse modulation signal indicating the On period and Off period of the pulsed RF signal, the control signal being coupled to the modulator of the radio frequency circuit to modulate the RF signal to generate the pulsed RF signal and to control a signal level of the pulsed RF signal during the On period.
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