Gqrx / C++ update June 4, 2011: After establishing the basic framework for a GNU Radio receiver written in C++ it was time to start working on the GUI framework. As you may recall the GUI will be written in Qt and I am hoping that it will simplify porting the application to Mac OS X.
frequency
Frequency xlating filter vs. complex multiplication
When I upgraded the simple GNU Radio receiver to single side band, I decided to separate the band pass filter and the frequency xlating filter and the frequency xlating filter got equipped with a wide low pass filter instead. The low pass filter is useful but really not important. Therefore, I decided to replace the frequency xlating filter with a simple complex multiplication (aka. local oscillator) and thereby save some CPU cycles – I figured that removing a filter would save something.