| 摘要 |
Determination of the pointing accuracy of a commutated scanning beam aerial is effected by monitoring the phase of the signal received at a point where, at all times during its operation, a field is established by the aerial. The phase of the sampled signal is observed by comparing it with a second signal which is sampled elsewhere in the field region or which is derived from the RF signal source of the aerial. This comparison can be effected by heterodyning the two signals. Pointing accuracy is determined by comparing the signal produced by the heterodyning with a pre-recorded signal typifying that experienced when the pointing error is zero. The technique is applicable to commutated torus aerials and to aerials incorporating a linear array of radiators to which power is supplied from a commutated array of excitation elements via an electromagnetic lens.
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