| 摘要 |
In a system having plural signal-carrying channels, a phase shift is introduced between a signal in one of the channels and a reference signal for calibrating the individual channels. The phase shift is introduced by phase-shift apparatus responsive to a command signal directing the continuous monotonic increment of phase. The apparatus may be contained within each channel for use in the signal-carrying process, or may be placed in the reference channel for use solely in the calibration process. The phase incrementing introduces a frequency shift (a serrodyning) which produces a beat-frequency signal upon mixing a channel signal with a reference signal. The beat-frequency signal is phase locked to a modulation pattern of the command signal whereby a measurement of phase (or delay) can be made between the two signals for calibration of each channel within the system. |
