A method for detecting, in a real-time manner, a presence or an absence of a an anomaly in or a cyber attack onto a medical apparatus comprises the steps of capturing, with an antenna, one or more emissions of electromagnetic energy from the processing devices within medical apparatus; converting, with a receiver coupled to the antenna, the one or more emissions from an analog to a digital form; generating, with a controller, a digital signal in a time domain; converting, the digital signal from the time domain to a frequency domain, the digital signal containing a signature of cross modulation products from the non-linear attachments; processing, in the frequency domain, the signature of cross modulation products to determine mixing characteristics of the cross modulation products; and detecting, based on the mixing characteristics, the absence or the presence of the anomaly or the cyber attack.