| 摘要 |
<p>Limiting amplifier (116) removes amplitude variations from the input signal (110). Splitter (120) provides the constant amplitude signal to each of amplifiers (124A to 124H) via a respective switch (122A to 122H). The envelope of the input signal (110) is detected at (134) and digitised at (138). The bits of the digitised envelope signal are used to control switches (122A to 122H). The output ratings of amplifiers (124A to 124H) form a series wherein each successive output rating is twice the preceding one. Thus, the bits of the digitised envelope signal can be used to reconstruct the envelope of the output signal provided by combiner (126). Several of the amplifiers may be replaced by a single amplifier to simplify the circuit (210, Figures 2 and 3). The input signal may be digital removing the need for envelope detection (Figure 4). Errors in the output may be compensated using a feedback mechanism (Figures 5 and 6).</p> |
