| 摘要 |
A short-circuited directional coupler (3), across which a measurement voltage is picked up, is connected to a variable-frequency microwave generator (wobbulator) (1) via a high-precision line (2). On the basis of the relationship with the characteristic impedance of the high-precision line, the internal impedance of the generator itself can then be determined by measuring the frequency-dependent maximum value Umax and minimum value Umin of this measurement voltage and calculating the reflection factor ri of the internal impedance of the generator in accordance with the equation ri = Umax - Umin/Umax + Umin. The method according to the invention is particularly applicable to a highly accurate determination of the internal impedance of an active radio-frequency chip (microwave generator), particularly if the characteristics of this chip are influenced by an internal automatic control loop. <IMAGE>
|
