Abstract: A closed loop slaving device is provided for slaving a first component, the slaving device including a second component having a multiplicative noise. A compensation noise is added to the input signal of the slaving device, the compensation noise being substantially equal to the input signal of the slaving device multiplied by the multiplicative noise of the second component. A sigma-delta modulator is also provided to convert an analog input signal into a digital output signal by use of an analog-to-digital converter slaved in the closed loop slaving device.

Abstract: The present invention relates to a device for slaving a first component in a closed loop, a second component in the return circuit to the loop input having a multiplicative noise. It also relates to a sigma-delta modulator making it possible to convert an analog input signal into a digital output signal on the basis of an analog-to-digital converter slaved in a closed loop using this device. A compensation noise is added to the input signal of the slaving loop, the compensation noise being substantially equal to the input signal of the slaving loop multiplied by the multiplicative noise of the second component.

Abstract: The present invention relates to a sigma-delta modulator to convert an analog signal into a digital signal using an analog-to-digital converter slaved in a closed loop. The undecided bits at the output of the analog-to-digital converter are assigned the same values in the digital output signal from the modulator as in the digital signal returned to the input of the modulator.

Abstract: The invention relates to a method and a device for generating agitation noise, and the agitation noise obtained. A subject of the invention is a method for generating agitation noise comprising an arbitrary number of points, with predetermined histogram, shaped around at least one frequency comprising: the generation of noise by a succession of several sequences {h(kN+n)}1?n?N of M.N points (M, N integers?1), [S2]: the choosing for each sequence of M basic subsequence(s) {hlm(n)}1?n?N, m?M in a random and independent manner from among at least L basic subsequence(s) of N shaped points (L integer?1), [S4]: the choosing in a random and independent manner, for each sequence, of the sign. Thus, by not simply repeating the subsequence, the spectrum of the agitation noise obtained has no spectral lines. A second variant of the invention furthermore comprises [S6]: the choosing in a random and independent manner, for each sequence, of the direction of temporal reading of each of the chosen basic subsequences.

Abstract: The disclosure pertains to continuous-time filtering. More particularly, it relates to filtering in a feedback control loop, for example in a sigma-delta (??) modulator. The making of a filter for this type of application comes up against a major problem linked to the relativity between the amplitude and phase responses. This limits the possibilities of choice in order to take steps against the instability of the loop. A continuous-time filter with minimum phase variation carries out the bandpass integration of the signal presented at its input. The making of the continuous-time filter as a bandpass integrator raises the problem of achieving a compromise between gain variations and phase variations close to the ?1 critical point, This compromise must lead to the stability of the loop. This problem is resolved by using a continuous-time bandpass integrating filter comprising at least one resonance device with minimum phase variation.

Abstract: The disclosure pertains to continuous-time filtering. More particularly, it relates to filtering in a feedback control loop, for example in a sigma-delta (&Sgr;&Dgr;) modulator. The making of a filter for this type of application comes up against a major problem linked to the relativity between the amplitude and phase responses. This limits the possibilities of choice in order to take steps against the instability of the loop. A continuous-time filter with minimum phase variation carries out the bandpass integration of the signal presented at its input. The making of the continuous-time filter as a bandpass integrator raises the problem of achieving a compromise between gain variations and phase variations close to the −1 critical point, This compromise must lead to the stability of the loop. This problem is resolved by using a continuous-time bandpass integrating filter comprising at least one resonance device with minimum phase variation.

Abstract: The distributed acoustic reflection transducer has a reflection function which includes at least one reversal of sign, that is to say it possesses at least one reflector and, in general, a combination of reflectors, the center of which is at a distance of k.lambda./2+.lambda./4 from the center of the other reflectors, .lambda. being the wavelength corresponding to the central operating frequency of the transducer.The applications will be for the production of surface-wave filters in radio communication systems.

Abstract: It consists of several channels (V1, V2) in parallel, which exhibit an inter-transducer gap difference (2.sub.1 -4.sub.1 ; 2.sub.2 -4.sub.2) equal to an even multiple of the half-wavelength (.lambda.) at the central frequency, from one channel to the next, so as to cancel the delay line transfer function which corresponds to the direct path between transducers.

Abstract: A low loss microwave surface acoustic wave filter, comprising input (2, 3) and output (4, 5) transducers, acoustically associated with coupling transducers (6, 7).The relative positions of the transducers 2 to 7) and of their O reflectors are chosen, having regard to the weightings of the coupling transducers (6, 7) in order to obtain the desired transfer function for this filter.