A {fixed|fastened|mounted} optic attenuator is {a device|a tool} with a pre-set attenuation {level|degree|stage} {that {cannot|can’t|can not} be|that cannot be|that cannot be} modified. Fixed attenuators are usually used to permanently scale back the optical energy of a sign to a protected level for the receiver. A constantly variable attenuator is an attenuator that might be modified […]