In the absence of such a wave meter, you can systematically vary the repetition rate and the offset frequency to monitor how the beat frequency changes in response. (scientificamerican.com)
We also assess how school - search frequency changes based on the number of available charter schools in the search unit. (educationnext.org)
Making use of the high frequency changes in productivity growth over one - to five - year periods, we run a series of regressions to test this link more rigorously. (nakedcapitalism.com)