Function exp_sweep 

pub fn exp_sweep(
    sample_rate: f64,
    f_start: f64,
    f_end: f64,
    duration: f64,
    amplitude: f64,
) -> Vec<f64>

Generate an exponential (logarithmic) frequency sweep.

Sweeps from f_start to f_end over duration seconds. This is the standard sweep for frequency response measurement.