| 摘要 |
PURPOSE:To realize the calibration for the amplitude of two outputs, by swiching the local oscillating signals which are applied to two balanced mixers. CONSTITUTION:The input receiving signal is applied to balanced mixers 1 and 3, and the outputs of the mixers 1 and 3 are made to pass through low pass filters 2 and 4 to obtain two orthogonal outputs 8 and 9. The output of a local signal generator 6 is applied directly to one of the mixers 1 and 3 and applied to the other one via a 90 deg. phase shifter 5. A switch 10 switches the local oscillating signals to be applied to the mixers 1 and 3 to be connected to the N and C sides in the active mode and caliburation mode respectively. When the amplitude characteristics of outputs 8 and 9 are referred to as A and Adelta respectively, the outputs become Acosphi/2 and Adeltasinphi/2 in the active mode and Asinphi/2 and Adeltacosphi/2 in the calibration mode, respectively. Thus delta can be obtained from these output values. |
