def _fb_gain_formula(open_loop_gain: float, neg_feedback: float) -> float:
	"""
	Calculate gain based on open-loop gain and negative feedback

	:param open_loop_gain: open-loop gain
	:param neg_feedback: positive value, < 1
	:return: resulting gain
	"""
	return open_loop_gain / (1.0 + open_loop_gain * neg_feedback)