| 摘要 |
<p>A linear amplifier amplifies a radio frequency (RF) signal. The RF signal is amplitude modulated by modulating signals having a wide range of frequencies. The amplifier is of the type having a D.C. input port and a D.C. output port and includes a first transistor having first, second, and third electrodes. First biasing means is connected across the input ports for providing a first biasing voltage across the first and second transistor electrode. Second biasing means is connected across the output port for providing a second biasing voltage across the first and third transistor electrodes. Linearization resistance means is coupled to one of the first transistor electrodes for linearizing impedance components of the first transistor. At least one of the biasing means is an active circuit and includes a D.C. voltage source and at least one active element. The one biasing means provide a substantially constant, essentially resistive impedance over a substantial portion of the wide range of modulation frequencies at the associated port of the first transistor. The impedance is of value which is low relative to the impedance of the amplifier, as measured at the associated port with respect to ground and looking toward the first transistor.</p> |
