A frequency agile sequential amplifier circuit that includes first and
second RF amplifiers coupled by a SAW delay line, a double balanced mixer
coupling the first RF amplifier to the SAW delay line, the output of the
first RF amplifier providing a signal as a first input to the double
balanced mixer and a variable pulse generator coupled to both said first
and second RF amplifiers to cause them to sequentially and alternately
conduct, and a divide/2 circuit coupling said variable pulse generator to
said double balanced mixer as a second input at 1/2 the rate of said RF
amplifiers to cause the sequential amplifier circuit to achieve frequency
agility and to substantially maintain its sensitivity.