LPF

/**
 * @brief Applies a Low-Pass Filter to the input samples, adding inertia to the system.
 * @param y [in] previous/initial result of the function
 *          [out] new result
 * @param x new sample value
 * @oaram dt time between the previous and the new sample
 * @param rc time constant - the reference measurement time.
 *  The higher rc, the more inertia (less impact of a single x on y)
 */
static function lpf(out float y, float x, float dt, float rc)
{
    local float a;

    a = dt / (rc + dt);
    y = a * x + (1 - a) * y;
}