| 摘要 |
<p>A feedforward type amplifier having a signal cancellation loop includes a cancellation node, a gain controller (C1) and a phase controller (C2). Each controller provides a discrete tap steering signal that it modulates with a discrete tracer signal that takes on a preselected sequence of values. The sequence is chosen so that the tracer signal is mutually orthogonal to each other tracer signal over a preselected period. A gain and phase adjuster (GPA1) connected to the outputs of the controllers provides a controlled gain change and phase shift in the signal cancellation loop. A detector (D1), the input of which is connected to the cancellation node and the output of which is connected to the controllers outputs a measure of the envelope of the signal at the cancellation node. After the preselected period new values for the tap steering signals are obtained by multiplying the detector output by the respective tracer signal, each over the respective preselected period, summing each resulting series of values, and changing the tap steering signals to be modulated and presented to the gain and phase adjuster in accordance with the values of the respective sums.</p> |
