| 摘要 |
Power from an alternating signal having a frequency variable in a wide and relatively high range such as approximately 10 megahertz to 40 gigahertz is indicated by a detector. To calibrate the detector, an alternating signal is introduced from a source to a bridge including a regulating member such as a thermistor. The bridge also receives a direct voltage. The thermistor is maintained at a particular impedance such as 400 ohms, regardless of the power provided by the alternating signal, by varying the magnitude of the direct voltage. The alternating signal, which is regulated in accordance with the dc voltage, is also introduced to the detector. The detector output is introduced to a data processing unit which processes the detector output to indicate the power from the alternating signal. The output from the data processing unit is converted to an analog signal which is combined with the signal from the bridge to produce a resultant signal. The amplitude of the resultant signal is compared with a reference signal to produce an error signal which is introduced to the source of the alternating signal to obtain adjustments in the output from the source in a direction to minimize the error. In this way, the data processing unit provides an output alternating signal of regulated and variable amplitude. The output from the detector is also used to calibrate the alternating signal from the source when different attenuators are introduced into the system to provide different ranges of attenuation.
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