This timing action must be such that during the transmitted pulse (pulse width), only the transmitter
can be connected to the antenna. Immediately after the pulse is transmitted, the antenna must be
reconnected to the receiver.
The leading edge of the transmitted pulse causes the duplexer to align the antenna to the transmitter.
This action is essentially instantaneous. At the end of the transmitted pulse, the trailing edge of the pulse
causes the duplexer to line up the antenna with the receiver; however, this action is not instantaneous. A
small amount of time elapses at this point that is referred to as recovery time. Therefore, the total time in
which the receiver is unable to receive the reflected pulse is equal to the pulse width plus the recovery
time. Note that any reflected pulses from close targets returning before the receiver is connected to the
antenna will be undetected. The minimum range, in yards, at which a target can be detected is determined
using the following formula (pulse width and recovery time are expressed in microseconds or fractions of
microseconds):