(3) The depth of operation of the system can be varied 
without significantly changing the rotor frequency or amp- 
litude(s) of the system. 
(4) The amplitude(s) of operation of the system can be 
near—instantaneously switched full-off if on or full-on 
if of f at suitably selected zero-velocity points in the 
motions of the linkage machinery of the system, and this 
switching can be accomplished without producing any signif- 
icant impulsive loadings on any machinery of the system.* 
(5) The phase of the pi-ton velocity can be near-instantan- 
eously switched by 180° at suitably selected zero-velocity 
points in the motions of the linkage machinery of the sys- 
ten, and this switching can be eccomplished without producing 
any Significant impulsive loadings on any machinery of the 
system. 
(5) The basic frequency of the piston motion can be near- 
instantaneously switched between the rotor frequency and 
twice that frequency at suitably selected zero-velocity 
points in the motions of the linkage machinery of the system, 
and this switching can be accomplished without producing any 
significant impulsive loadings of any machinery of the sys- 
tem. 
(7) By suitable design techniques the harmonic content of 
the system's piston motions can be tailored and/or varied 
to satisfy various postulated specifications. 
*In particular, the amplitude of operation of the system can be 
switched full on for one or any odd number of half cycles, and 
then the amplitude can be switched full of£ again. 
ec: Hightower 
Pickens, Stixrud, Walton 
5C 
rrr en cc rnin SPE Om oper Teen 
