Analog Circuits Cookbook

Advanced circuit techniques,components and concepts 41

of frequency and has units of (rad/m)/(rad/s) = s/m. Thus 6/(0 = root(ZC)

has units of seconds delay per metre for the particular cable in question,

and the reciprocal of this has units of metres per second, giving v

—

(0/B

directly. That excellent if ancient textbook, The Handbook of Line

Communications,

calls v the phase or wave velocity, adding darkly, without

further explanation, that 'the group velocity (i.e., the velocity at which energy

is transferred along the line) is dco/dB'. In the present case of a transmission

line,

where B is directly proportional to

CO,

their ratio is constan ...