Abstract: A surgical instrument, has an end effector that includes an ultrasonic blade, and a clamp arm that moves relative to the ultrasonic blade from an opened position toward an intermediate position and a closed position. The clamp arm is offset from the ultrasonic blade to define a predetermined gap in the intermediate position between the opened position and the closed position. A clamp arm actuator connects to the clamp arm and moves from an opened configuration to a closed configuration to direct the clamp arm from the opened position toward the intermediate position and the closed position. A spacer connects with the clamp arm to inhibit movement of the clamp arm from the intermediate position toward the closed position for maintaining the predetermined gap between the clamp arm and the ultrasonic blade.

Abstract: A microwave oscillator in a loop configuration comprises three substantially identical amplifier stages each having its own phase shift at a selected oscillating frequency. A transmission delay element having a phase shift at the selected oscillating frequency, is also in the loop configuration, so that the oscillator has zero phase shift around the loop at the oscillating frequency. Each amplifier stage has at least one active component with resistive feedback, which is connected to DC blocking and filtering capacitors. Capacitor values between 2.2 and 5.1 pf are used making the oscillator design amenable to cost effective conventional hybrid and semiconductor processes.

Abstract: A voltage controlled oscillator is tuned with a network comprising two varactor diodes and two transmission lines. By selecting appropriate values of varactor capacitance and transmission line length and width the overall reactance of the network is such that, when a varactor tuning voltage is varied, the output frequency of the voltage controlled oscillator will vary in an fashion with respect to the tuning voltage. Such a voltage controlled oscillator is gain compensated and exhibits a controlled modulation sensitivity over a range of frequencies. If the required frequency range of the oscillator is known beforehand, an alternate embodiment of the invention may be employed in which one of the varactor diodes is replaced with a fixed capacitor having a suitable value for the desired frequency range.