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Estimates the cycle frequency based on time and phase

get_frequency.Rd

Estimates frequency based on time and phase by one of two methods:

  • 'deriv' Takes the derivative of phase vs time to get frequency

  • 'slope' Fits a line to phase vs time and uses the slope as an estimate of frequency.

Usage

get_frequency(
  t,
  ph,
  unwrap = FALSE,
  method = "deriv",
  mod = 2 * pi,
  check_reasonableness = TRUE
)

Arguments

t

Time

ph

Phase

unwrap

(TRUE or FALSE) Unwrap the phase. Note that the function will not work unless the phase is unwrapped, so you should only set unwrap to FALSE if the phase has been unwrapped earlier.

method

('deriv' or 'slope') Estimate the frequency based on

mod

Modulus for the phase. Default is 2*pi.

check_reasonableness

Runs some simple checks to make sure the data make sense. Checks to make sure phase is mostly increasing and warns if it isn't.

Value

The frequency estimate, either as a vector the same size as ph (for the 'deriv' algorithm) or as a single value (for the 'slope' algorithm)

Examples

t <- seq(0, 3, by=0.1)
# example phase that has a frequency of exactly 2.3 Hz
ph <- 2*pi*(t * 2.3)

get_frequency(t, ph)
#>  [1] 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3
#> [20] 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3