초록 ▼

A cordless telephone system connectable to the public switched telephone network having a base station and one or more handsets communicating with the base station by an RF link using a time division duplex direct sequence spread spectrum quadrature modulation technique, having a gain imbalance comp

A cordless telephone system connectable to the public switched telephone network having a base station and one or more handsets communicating with the base station by an RF link using a time division duplex direct sequence spread spectrum quadrature modulation technique, having a gain imbalance compensation system for balancing the gain between the I and Q channels. Gain imbalance estimation is performed as part of a calibration cycle when the handset is in the cradle of the base station. The controller of the unit causes another unit to send a data signal with a frequency error. The baseband receiver performs the operation .vertline.I.vertline.-.vertline.Q.vertline., which is an indication of gain error. The results are stored in an accumulator over a set period of time. The controller reads the accumulator and uses an iterative process, increasing or decreasing the gain link compensation until no gain imbalance error is obtained.

대표청구항 ▼

[ What is claimed is:] [1.] In a direct sequence spread spectrum communication link, a gain imbalance compensation circuit connected to balance the gain between the receive in-phase and quadrature baseband signal channel, the gain imbalance compensation circuit comprising:means for introducing a fre

[ What is claimed is:] [1.] In a direct sequence spread spectrum communication link, a gain imbalance compensation circuit connected to balance the gain between the receive in-phase and quadrature baseband signal channel, the gain imbalance compensation circuit comprising:means for introducing a frequency offset signal into the in-phase and quadrature signal channels during the time the communication link is in standby;means for detecting a gain imbalance between the resulting signals in the in-phase and quadrature channels; andmeans for increasing or decreasing the gain in the in-phase and quadrature signal channels until the gain in the in-phase and quadrature channels are in balance.