Patent ID: 7502599
Filing Date: 2009-03-10
Classification: H03F

Abstract:
1. A Cartesian loop transmitter having a forward path and a feedback path, each of these paths comprising an I-channel and a Q-channel, as well as an isolator eliminator, said transmitter comprising: a) a first low pass filter and a first wide band pass filter connected to said I-channel at LP b) a second low pass filter and a second wide band pass filter connected to said Q-channel at LP c) a first root mean square detector collecting signals from said first wide band pass filter; and from said second wide band pass filter; d) a second root mean square detector collecting signals from said first low pass filter and from said second low pass filter; e) a first divider connected to said first and said second root mean square detectors to produce a first ratio using signals from said first and said second root mean square detectors; and f) a means for comparing connected to said first divider, the means for comparing comparing the first ratio to a first threshold, the means for comparing providing a signal; and g) a digital system connected to input attenuators on said I- and Q-channels and to the means for comparing, the digital system controlling an attenuation setting of the transmitter based on the signal from the means for comparing.