| 摘要 |
A technique for calibrating the open-loop transmit power of a wireless communication device overcomes the inherent nonlinearities in the gain contr ol input of a variable gain amplifier (VGA). In one embodiment, a feedback circuit generates a signal indicative of the transmit power. This signal is compared with a desired transmit power level, which comprises an open-loop gain component and a closed-loop gain component. The desired transmit power level is compared with the actual transmit power level and an error signal i s generated. The error signal is used to alter the gain of the VGA in the transmitter to thereby adjust the actual transmit power level to correspond with the desired transmit power level. In alternative embodiment, the receiv er portion, which also contains a VGA, is pre-calibrated in a conventional manner. During a transmitter calibration process, the transmitter is coupled to the receiver input through a mixer and filter. The pre-calibrated receive r determines the actual transmit power level. The difference is used to genera te error correction data to adjust for non linearities in the gain control inpu t of the transmitter VGA. |
