A Computer Subsystem Using Kilomegacycle Subharmonic Oscillators

An investigation was made of the problems associated with a high-speed carrier computer, and a computer subsystem was constructed employing subharmonic oscillators driven with a 3.7-kMc sine wave source. The three-phase power source was modulated at a 30-Mc rate so the interval between successive logic operations was 11 nsec. The logic module is a balanced resonant varactor circuit having a pulsed subharmonic output at 1.85 kMc and a rise time of 3 nsec. The output from each module, at a level of about 1 mw, is distributed through a network of resistors and coacial lines to the modules of the succeeding power supply phase. The logic is done at 1.85 kMc by forming a majority of three from the three inputs. Thi majority logic, with the readily available inversion operation, provides a universal set of logic gates. The subsystem consists of four main parts: the logic modules, the 1.85-kMc signal distribution, the 3.7-kMc power distribution, and the power supply. The subharmonic oscillator has advantages characteristic of a carrier computer; among these is the ability to transform impedance levels, and the ability to get a logic inversion by adding a cable length to give 180° phase change of the signal. Advantages peculiar to the subharmonic oscillator system are the simplicity of the varactor and its inherently fast operation. This approach also has a high logic gain, and provides fully timed and amplitude limited pulses at the output of each module. Three-phase operation gives an effective directivity to the single port gate.