The tight duty cycle for an oscillator assesses the uniformity or symmetry of the output waves. To have completely perfect waveforms in terms of symmetry, the waveform would be in a perfect logic high state exactly 50% of the time and in a logic low state the other 50% of the time. This is expressed as 50/50%. A measurement of 45/55% is considered a tight duty cycle in terms of the symmetry of the output waves for an oscillator.
