The question was unexpectedly and suddenly answered for her, by the colourless boy, Bitzer, who came round the corner with such blind speed
and so little anticipating a stoppage on the pavement, that he brought himself up against Mr.
Diversity is widely used in radar signals, beginning with diversity of the pulse interval (Chapter 8), which mitigates blind speeds
. More elaborate diversity schemes are presented in Chapter 9, with emphasis on step-frequency pulses.