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Description
Because of the aging, and product discontinuity, LANSCE is investigating the replacement of klystrons . One of the highly promising amplifiers are the GaN amplifiers. Currently available GaN amplifier can produce 5kW pulse RF power. Hence, a multitude of Solid-State Power Amplifiers (SSPA) combined together to produce the equivalent or better performance than the klystron. For a high drain voltage, the drain power dissipation is increased as the operating efficiency becomes low. In order to operate the SSPA at high efficiency, the operating of the amplifier is as close as possible to the saturation region of amplifier’s amplitude characteristic curve. The outphasing technique provides this requirement of the SSPA operation. The outphasing amplifier converts the Amplitude Modulation-Phase Modulation(AM-PM) signal to two constant envelope PM signals, so that each amplifier of two signal path linearly amplifies constant envelope PM input signals. The combiner combines two amplified PM signals, yielding the signal of linear amplification of the input signal. The core part of the outphasing amplifier is the signal component separator(SCS) in which the AM-PM input signal is converted to two constant envelope PM signals.
Most SCS techniques are implemented on the analog circuits in polar coordinate(amplitude-phase domain). In this paper, a digital signal component separator (DSCS) in In-phase/Quadrature(I/Q) coordinate is proposed. The DSCS is implemented on the present Field Programmable Gate Array(FPGA) based LANSCE digital low level RF (DLLRF) control system. The performance of the DSCS is verified on a low power teststand and the results are reported.
| Abstract Category | Measurement and Control |
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