3G RADIO

摘要

In a UMTS homodyne (direct conversion) receiver the local oscillator may break through as an "on channel" signal. In order to remove this the receiver includes controllable DC offset generators and variable gain amplifiers. These are in series with a high pass filter. Adjustments in the gain or offset can give rise to transients within the filter which effectively blind the receiver until such time as the transients have decayed within the filter. This blind time can be reduced by increasing the bandwidth of the filter during such a transient.