| 摘要 |
<p>An R.F. transmitter circuit has an amplifier (30), a matching network (40) coupled to an output of the amplifier, a programmable resistance (35) coupled to the output of the amplifier, and a controller (60) arranged to control the programmable resistance, and to determine a matched output impedance of the amplifier by detecting a change in the amplifier output for different values of the programmable resistance. This output impedance can be used to adjust the matching to achieve optimum gain or optimum efficiency or other characteristic, during manufacture, test, or in use.</p> |
