Cardiorespiratory synchrogram

The classic Schafer-Rosenblum synchrogram: the respiratory phase observed at each heartbeat, wrapped into m respiratory cycles. Under n:m locking (n heartbeats per m breaths) the points collapse onto n horizontal bands.

Usage

synchrogram(resp_phase, rpeaks, m = 1L)

Arguments

resp_phase

Instantaneous respiratory phase (length = n samples), e.g. from instantaneousPhase().

rpeaks

Integer R-peak sample indices.

m

Number of respiratory cycles to wrap into (default 1).

Value

A data frame with beat (R-peak sample index) and psi (respiratory phase at that beat, in [0, m)), of class "synchrogram".

Examples

t <- seq(0, 120, by = 0.01); fs <- 100
resp_phase <- instantaneousPhase(sin(2 * pi * 0.25 * t), fs)
rpeaks <- which(diff(sign(sin(2 * pi * 1.0 * t))) > 0)   # ~1 Hz beats
sg <- synchrogram(resp_phase, rpeaks, m = 1)