E4E12 (A)
What is one disadvantage of using some types of automatic DSP notch-filters when attempting to copy CW signals?
A. A DSP filter can remove the desired signal at the same time as it removes interfering signals
B. Any nearby signal passing through the DSP system will overwhelm the desired signal
C. Received CW signals will appear to be modulated at the DSP clock frequency
D. Ringing in the DSP filter will completely remove the spaces between the CW characters
