Patent ID: 8577320

Claim:
An apparatus comprising a detector of oscillations in a frequency band around a first frequency in a received radio-frequency electrical signal, said detector comprising an acquisition terminal for receiving said radio-frequency electrical signal, and a radio-frequency oscillator to be synchronized with said first frequency, said radio-frequency oscillator comprising at least one magnetoresistive device within which flows a spin-polarized electrical current for generating an oscillating signal at an output electrode, said at least one magnetoresistive device being formed by a stack of magnetic and non-magnetic layers, a synchronization terminal for synchronizing a frequency of said oscillating signal with a frequency of a signal received at said synchronization terminal, said synchronization terminal being connected to said acquisition terminal, and at least one of a current source to cause a continuous current of electrons to flow perpendicularly through said layers and a continuous magnetic field generator, said at least one said current and said continuous magnetic field being configured so that a free frequency of oscillations of an oscillating signal produced in absence of a signal at said synchronization terminal is, within ±60%, equal to said first frequency scaled by a positive rational number, an electronic comparator capable of automatically distinguishing a synchronized state of said radio-frequency oscillator from a non-synchronized state of said radio-frequency oscillator on the basis of an oscillating signal produced by said radio-frequency oscillator, said synchronized state being a state in which a power level of low-frequency components of said oscillating signal produced by said radio-frequency oscillator is below a predetermined power threshold, and said non-synchronized state being a state in which a power level of said low-frequency components of said oscillating signal produced by said radio-frequency oscillator is above said predetermined power threshold, said low-frequency components consisting of components having a frequency below 1 gigahertz, and indicating presence of oscillations in said frequency band around said frequency in said received radio-frequency electrical signal when said oscillator is in said synchronized state, and indicating absence of oscillations in said frequency band in said received radio-frequency electrical signal otherwise.