Abstract: Apparatus and methods for radio frequency (RF) signal limiting are provided. In certain embodiments, an RF signal limiting system includes a cascade of a front limiter and a biased limiter. Additionally, the front limiter provides an initial amount of limiting to an RF signal, while the biased limiter serves to further limit the RF signal. The biased limiter is adaptively biased such that the amount of limiting provided to the RF signal increases in response to an increase in the RF signal level. Such an RF signal limiting system can be used in a variety of applications, including protecting an input of a low noise amplifier (LNA).

Abstract: Apparatus and methods for radio frequency (RF) signal limiting are provided. In certain embodiments, an RF signal limiting system includes a cascade of a front limiter and a biased limiter. Additionally, the front limiter provides an initial amount of limiting to an RF signal, while the biased limiter serves to further limit the RF signal. The biased limiter is adaptively biased such that the amount of limiting provided to the RF signal increases in response to an increase in the RF signal level. Such an RF signal limiting system can be used in a variety of applications, including protecting an input of a low noise amplifier (LNA).

Abstract: In various implementations of a load modulated balanced amplifier (LMBA), a control signal is generated (e.g., automatically generated) based at least in part on an input signal. The LBMA generally comprises a balanced amplifier, an input splitter, and a control path. A common theme of the different variants described below is that we use a nonlinear characteristic to generate a power-dependent asymmetry in the relative output power levels of the balanced and control amplifiers. This power-depended asymmetry results in dynamic load modulation of the balanced amplifiers, which in turn provides improved efficiency. In one implementation, for example, an LMBA comprises a pair of primary amplifiers collectively providing a balanced amplifier and a control amplifier coupled to the balanced amplifier and adapted to provide a control signal to the balanced amplifier.

Abstract: In various implementations of a load modulated balanced amplifier (LMBA), a control signal is generated (e.g., automatically generated) based at least in part on an input signal. The LBMA generally comprises a balanced amplifier, an input splitter, and a control path. A common theme of the different variants described below is that we use a nonlinear characteristic to generate a power-dependent asymmetry in the relative output power levels of the balanced and control amplifiers. This power-depended asymmetry results in dynamic load modulation of the balanced amplifiers, which in turn provides improved efficiency. In one implementation, for example, an LMBA comprises a pair of primary amplifiers collectively providing a balanced amplifier and a control amplifier coupled to the balanced amplifier and adapted to provide a control signal to the balanced amplifier.