Abstract: Two or more distributed amplifiers are paralleled to increase the available output power. Phase shifters are coupled to the amplifiers as necessary to maximize output power at a frequency. With this phase adjustment, the amplifiers may have effective electrical lengths which differ one from another by N (360.degree.), where N is zero or an integer. Values of N other than zero undesirably reduce the instantaneous bandwidth of the paralleled amplifiers. The bandwidth is maximized by the addition of sufficient delays to reduce N to zero.

Abstract: A cylinder head 1 has four valves 2, 4 per cylinder and the desirable arrangement whereby the sparking plug 7 electrodes are in the center of the four valves. The sparking plug 7 is housed in a tube 29 to protect it from the oil in the valve gear region of the head. By appropriate choice of dimensions, it has been found possible to operate the valves 2, 4 via rockers 9, 11 by means of a camshaft 18 located in the vee-space between the valves, while still allowing room to accommodate the sparking plug 7. A desirable compactness is thereby achieved.

Abstract: A continuously variable ratio transmission of the rolling friction type has a hydraulic control circuit including an end loading device for the transmission located upstream of a double sided piston used to balance roller reaction torque, and a valve for controlling the force exerted by the double sided piston. The valve has two outlets each feeding one side of the piston and communicating with the transmission's sump by way of a device for equalizing the flow rates from the two outlets to the sump. A feedback arrangement provides that the force exerted on the spool of the control valve is always proportional to the force exerted by the piston. The piston travel is limited by hydraulic end stops, upstream of which is provided a pressure relief valve to eliminate damaging transient overloads being exerted by the end loading device. The circuit also includes a facility whereby normal electrical/electronic control of the control valve can be overridden in an emergency.