| 摘要 |
Two microwave signals of identical frequency, possibly differing in amplitude and/or phase from each other, are combined by feeding them to respective inputs of a directional coupler with outputs each carrying an unshifted component of one and a quadrature-shifted component of the other input signal. The composite output signals of the coupler are fed to a hybrid junction which combines them cophasally into a sum signal and with relative phase inversion into a difference signal. The sum signal, besides energizing a load, is applied directly to a reference input of a first coherent detector and through a 90 DEG phase shifter to a reference input of a second coherent detector each receiving the difference signal on a monitoring input. The first detector controls a phase shifter upstream of one of the coupler inputs to correct for phase deviations while the second detector controls a phase shifter downstream of one of the coupler outputs to correct for changes in relative amplitude. The hybrid junction may be a Magic T, or another directional coupler preceded by a 90 DEG phase shifter in series with one of its inputs.
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