Why are direct or flash conversion analog-to-digital converters used for a software defined radio?
Very low power consumption decreases frequency drift
Immunity to out-of-sequence coding reduces spurious responses
Very high speed allows digitizing high frequencies✓Correct answer
All these choices are correct
Explanation
A flash converter resolves an entire sample in one clock cycle using a bank of parallel comparators, which gives the very high sampling rates a software defined radio needs to digitize high frequencies directly. That speed comes at the cost of high power consumption and a large comparator count, so the combined answer is wrong.