Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Centre National De La Recherche Scientifique

Michaël Quinsat

Marie-Claire Cyrille

Ursula Ebels

Jean-Philippe Michel

Dimitri Houssameddine

Bertrand Delaet

Patrick Villard

Mykhailo Zarudniev

Michaël Pelissier

Marie- Claire Cyrille

The invention relates to a radiofrequency oscillator which incorporates: a spin-polarized electric current magnetoresistive device (), a terminal () for controlling the frequency or amplitude of the oscillating signal, a servo loop () connected between the output terminal and the control terminal for applying a control signal to the control terminal in order to slave a characteristic of the oscillating signal to a reference value, the servo loop () comprising: a sensor () of the amplitude of the oscillating signal oscillations, and a comparator () capable of generating the control signal according to the measured amplitude and the reference value.

Magnetoresistive radiofrequency oscillator and method for generating an oscillating signal

The invention relates to a radiofrequency oscillator which incorporates: a spin-polarized electric current magnetoresistive device () for generating an oscillating signal at an oscillation frequency on an output terminal (), and a terminal () for controlling the frequency or amplitude of the oscillating signal, and a feedback loop () comprising an amplifier () provided with: an input connected to the output terminal () of the magnetoresistive device () so as to amplify the portion of an oscillating signal detected at the output terminal, and an output connected to the control terminal () so as to inject onto said control terminal the amplified portion of the oscillating signal which is phase-related to the oscillating signal generated at the output terminal.

A demodulator of an FM signal modulated about a carrier frequency with a modulation frequency has an RF oscillator configured to be synchronized, under identical conditions of operation, with oscillations at first and second frequencies used in the FM signal to encode respective pieces of information. The oscillator has a magnetoresistive device; and a low-pass filter connected to an output electrode of the magnetoresistive device to filter an oscillating signal, generated by the oscillator and to a rendering terminal to provide, as a demodulated electrical signal, the filtered signal, the cut-off frequency fat &#x2212;3 dB of this filter being strictly lower than the frequency and higher than the modulation frequency.

Demodulator of a frequency-modulated electrical signal

A synthesizer includes a second frequency-synthesizing stage comprising a radiofrequency oscillator configured to oscillate at a frequency &#x3b1;fo when it is synchronized with a signal s(), where &#x3b1; is a rational number different from one such that &#x3b1;f=ft. The radiofrequency oscillator has a magnetoresistive device within which there flows a spin-polarized electrical current to generate a signal st(t) oscillating at the frequency ft on an output electrode connected to the rendering terminal. This device is formed by a stack of magnetic and non-magnetic layers, a synchronization terminal for synchronizing the frequency of the oscillating signal st(t) with the frequency of the signal received at the synchronization terminal. The synchronization terminal being connected to the output terminal of the first stage to receive the signal s().

Synthesizer of an oscillating signal

An oscillation detector having an RF oscillator configured to be synchronized with a first frequency and a comparator for distinguishing the synchronized state from the non-synchronized state of the radiofrequency oscillator on the basis of an oscillating signal produced by the radiofrequency oscillator and indicating the presence of oscillations in a frequency band around the first frequency in response to identifying the synchronized state and, in alternation, indicating the absence of oscillations in this frequency band otherwise.

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Grenoble, France

Michaël Quinsat