| 摘要 |
<p>A phase differential determining apparatus generates low frequency output signals from a multiple channel receiver and extracts relative phase angles of the received RF signals therefrom. The same local oscillator signals, which are phase locked to one of the received RF signals, are utilized for all channels thus preserving the phase difference of the RF signals during the heterodyning process so that phase angle differences between the low frequency output signals is the same as the phase angle differences between the received RF signals. The relative phase angles are determined at the low frequency output level by phase shifting a low frequency signal from the local oscillator that is phase locked to a reference channel and varying the phase shift applied thereto until the phase difference between this low frequency local oscillator signal and the low frequency output signal of the selected channel is zero. The phase shift introduced to the low frequency local oscillator signal is equal to the difference in phase between the two RF signals.</p> |
