Modulators are substances or devices that influence the activity of other molecules or systems. In biology, they can enhance or inhibit the effects of neurotransmitters, hormones, or enzymes, thereby affecting various physiological processes. For example, a neurotransmitter modulator can alter the strength of signals between neurons, impacting mood and behavior. In technology, modulators are used in communication systems to modify signals for transmission. They can change the amplitude, frequency, or phase of a carrier wave, allowing information to be sent over distances. This is essential in devices like radios and televisions, where clear signal transmission is crucial for effective communication.