| 摘要 |
<p>A receiver removes a direct current (DC) offset component from a received Code Division Multiple Access (CDMA) spread spectrum signal. The DC offset is attributed to both spreading code imbalance as well as conversion between analog and digital formats. In operation, received data is de-spread using an appropriate de-spreading code. Thereafter, a DC offset removing circuit employs a positive/negative counter counting each occurrence of positive and negative chips to produce a chip imbalance for each chip in the spreading code. The measured imbalance is multiplied by the received data signal, an RF component of this multiplied output is removed by a low-pass filter, and thereafter, the signal is again multiplied by the chip imbalance. The DC offset components in the received signal are removed by subtracting the second multiplied signal from the received data signal.</p> |
