| 摘要 |
Power amplifiers in semiconductor amplifier element construction, such as are used, in particular, as output stages for shortwave transmitters, require a control device for stabilising the temperature of the operating point in order to ensure the optimum intermodulation ratios are also achieved with full drive of the amplifier elements, independently of the operating temperature. As has been shown in practice, the temperature probes (TF) arranged at the semiconductor amplifier element housing can only incompletely detect the temperature changes actually occurring in the semiconductor in dependence on the drive, so that in the event of fast changes in the drive of such amplifier element units (EVS1, EVS2, ... EVSn), an unwanted displacement of the operating point occurs. It is proposed to considerably improve the temperature stabilisation of the operating point of such semiconductor amplifier elements by the fact that a further measurement variable derived by rectification of the RF output energy is superimposed on the electrical measurement variable supplied by the temperature probe, in such a manner that the aggregate measurement variable is also effective with increasing RF output energy in the direction of a temperature increase and conversely. <IMAGE> |
