| 摘要 |
<p>The present invention relates to the field of amplifiers comprising one or more field effect devices as the active amplifying element and/or as load devices in amplifier circuits. The drawbacks to using prior art techniques are many. Very high voltage gains are not possible without power supply voltages which greatly exceed the drain-source voltage. Further, prior amplifiers are relatively non-linear, and because the amplifier is unsymmetrical, the distortion of an AC input is also unsymmetrical, giving rise not only to high-third and other odd harmonics, but also high-second and other even harmonics. Also, obviously, the output is highly sensitive to power supply fluctuations. The present invention overcomes these deficiencies by providing a field effect transconductance amplifier having improved linearity and noise rejection characteristics to provide an amplifier output having excellent temporal coherence with the input signal. The amplifiers utilize a series connection of two field effect devices, actual or emulated, preferably appropriately biased in a carrier velocity limited region to maximize linearity of the output. A high level of rejection of power supply noise may be achieved by a third series field effect device. Various embodiments including high gain and power amplifier embodiments are disclosed. </p> |
