Analog Circuits Cookbook

36 Analog Circuits Cookbook

time.

If a very high input impedance buffer amplifier were hung on one end

of the line, a sample of the rf would be available almost indefinitely, giving

a signal which was greatly 'stretched' in time. Receiving a radar pulse and

retransmitting it at low level in such a stretched form is the basis of one type

of countermeasure used in electronic warfare. The fact that a line of (about)

200 000km provides a delay of

1

s (i.e. the signal travels at about two-thirds

the speed of light) comes about as follows:

^0

= V (L/C) (see Unit discussion below)

where L and Care the inductance and capacitance of any length of

line ...