John Hobdell has written:

'P.S.K. regeneration using a subharmonic oscillator'

Kevin Cheung has written:

'Probing the behaviour of the subharmonic energy from microbubbles at high ultrasound frequencies'

J. H. van Oorschot has written:

'Subharmonic components in hawser and fender forces'

Reda R. Mankbadi has written:

'Phase development and its role on subharmonic control' -- subject(s): Jets, Resonance, Stability

I assume you mean measure the frequency of vibration of a mechanical system or part. You use a stroboscope, which is a light that flashes briefly and rapidly. You shine the light on the object and adjust the frequency of the strobe by turning a dial until the object stops moving. You then read the dial to determine the frequency. there are steps you have to take to avoid synchronizing to a subharmonic of the base frequency. For example, if the object is vibrating at 100Hz (10ms), running the strobe at 50hz will also stop the motion, as it will pick up every other cycle.