Abstract: The method according to the invention is applicable to motors comprising a magnetized rotor having two diametrically opposed poles, a stator making up a magnetic circuit having saturable constricted portions and a coil coupled magnetically to the stator. The method consists in applying to the coil an electric pulse, in measuring a control current (I'.sub.01, I'.sub.02) generated within the coil by the electric pulse at the end of a control time interval (t'.sub.o -t.sub.i) and in comparing the control current with a reference current (I.sub.r), the sign of this comparison being representative of the position of the rotor. In order to take into account the variations in the characteristics of the motor with time, the control time interval (t'.sub.o -t'.sub.i) is readjusted periodically by means of first and second electric pulses of a learning signal applied to the coil. The first pulse of this signal generates within the coil a first current (I.sub.1) which reaches the reference current (I.sub.

Abstract: A pager is described for use in an electronic watch. The pager comprises a frame (1) for picking up a magnetic signal and a piezoelectric transducer (11) having a static capacitance on its terminals, for producing a sound. 11To improve sensitivity of reception, a switching circuit (15) connects the transducer (11) in parallel with the frame (1) to tune it by means of the static capacitance to the frequency of the magnetic signal carrier wave. To increase the performance of the transducer (11 ) when it operates as a sound transmitter, the switching circuit (15) connects the frame (1) in series with the transducer (11).

Abstract: This transponder includes a dielectric support, an antenna and a covering layer. The central portion of the antenna forms a self induction loop which, together with the junction capacity of a non-linear component serving to close the loop, provides a circuit resonating at the frequency at which the transponder receives its energy. The antenna radiates energy at double this frequency which energy may be detected by a receiver.

Abstract: A piezoelectric oscillator is described comprising a piezoelectric element, e.g. a tuning fork (10), and a casing (20) formed by a pair of glass plates (22,24). The inner surfaces of the plates have recesses (26,27) that define a housing (28) in which the tuning fork (10) is located, and a pedestal (22a) to which the tuning fork (10) is secured. The inner surface of one of the plates (22) carries a conductive track (30), in the region of the pedestal (22a). This plate (22) is also formed with a hole (44) opening onto the conductive track (30) which seals it off.

Abstract: Some at least of the control signals usually produced by manual control members and applied to the control circuit of the watch to control the performance of the different functions thereof are produced directly from words pronounced by the user, belonging to a pre-determined vocabulary, by an assembly for producing control signals by means of speech, which comprises electro-acoustic means for converting a pronounced word into an analog signal representing that word, means for transforming the analog signal into an item of logic control information and means for transforming the logic information into a control signal which can be directly applied to a control circuit for controlling performance of the function corresponding to the word pronounced.

Abstract: The timepiece comprises an oscillator (1), a frequency divider (2), a control circuit (3), a stepping motor (4), a seconds hand (5), a circuit (7) for detecting steps missed by the motor, an up-down counter (15) having a capacity N, and a flip-flop (16). At each missed step the detecting circuit (7) generates a tally pulse (S.sub.7) which increments the counter (15). The latter is also decremented by periodic pulses appearing on the B output of the frequency divider (2).When a cell supplying the timepiece is nearly exhausted, the number of steps missed per unit of time is high and the counter (15) is, on balance, incremented. When passing from state N-1 to state N the counter issues on its Q.sub.h output a pulse that causes the Q output of the flip-flop (16) to go high. The control circuit (3) produces, in response to this high state of the flip-flop, a signal warning of the imminent end of the cell's life in the form of an irregular motion of the seconds hand (5).

Abstract: A resonator (1) is described for vibrating in a thickness-shear mode and has auxiliary electrodes (7f, 8d) between the zone of its main excitation electrodes (3, 4) and the zone of its connection terminals (5, 6) to generate an auxiliary vibration in opposition of phase with respect to the main vibration.The presence of the auxiliary electrodes (7f, 8d) improves notably the quality factor of the resonator.

Abstract: The micro-resonator comprises, cut from the same quartz crystal, a bar and a suspension frame means. The bar is cut in a substantially Z cut mode. The excitation electrodes are disposed on the sides of the bar. The length of the bar is substantially parallel to the Y axis.This produces a resonator which vibrates in a main mode of extension-compression, at from 0.5 MHz to 4 MHz.

Abstract: In a speech recognition and control apparatus, the speech signal is filtered into sub-bands, each sub-band signal sampled and binary quantized to form a digital string which is simplified (data reduced or compressed) by further encoding based on detecting in the string an isolated sample having one binary value surrounded by two samples having the other binary value.

Abstract: The method comprises measuring the voltage induced during the driving pulse in the coil by rotation of the rotor, and interrupting the drive pulse in dependence on the measurement made.The device for carrying out this method comprises a circuit for measuring the induced voltage, a circuit for comparison with a reference value and a circuit for calculating the duration of the drive pulse.

Abstract: The column electrodes of the display device are each formed by an alignment of conducting areas which are electrically connected to each other and which are spaced from each other, while disposed between two successive conducting areas of each electrode, in alignment with said conducting areas is a conducting area of an adjoining electrode. n+1 different reference signals are produced such that the effective value of the difference between two different signals is sufficient to generate an electro-optical effect. The first n signals of said signals are each applied to a line electrode. A signal selected from the above-mentioned n+1 signals is applied to each column electrode said selection being made in dependence on the value of a control signal.

Abstract: The counting circuit described issues a numerical information which is a non-linear function of the number of pulses applied to its input.The circuit comprises dividers which divide by integers K.sub.i the pulses applied to their inputs. A first selector connects the output of one of the dividers to the input of a counter in response to a first signal. The content of the counter is compared with numbers k.sub.i by comparators. The output of one of the comparators is connected to a control circuit by a second selector controlled by a second signal issued by the control circuit in response to a comparison signal.

Abstract: To compensate for frequency variation in the quartz oscillator 4, 6 due to temperature variation, a second quartz oscillator 12, 14 forming a thermal sensor is employed. The beat frequency fB (circuit 16) which is counted in the counter 26 for a period of time T.sub.1 gives a measurement corresponding to temperature. The number which is thus counted is raised to its square and by means of the comparator 30 taken away from the pulses counted by the divider 8 with a periodicity T.sub.T. The system may be used to provide temperature compensation for a time keeping quartz time base.

Abstract: The pressure sensitive element described has an improved barometric coefficient. The sensitive element essentially consists of a piezoelectric tuning fork having a base and a pair of arms. At the end of each arm are provided slots that are parallel to the flanks of the arms. The slots extend all the way through the thickness of the arms. The sensitive element is particularly suited for use in gas pressure measuring sensors.

Abstract: Speech recognition is improved by adaptive update of reference word codes. The apparatus can be used for controlling a piece of equipment and comprises memories which in coded form contains the references of the vocabulary of the machine; a microphone, a coding circuit and a memory for coding and memorizing the word pronounced by the user; a device for displaying the word recognized by the apparatus; and a control circuit for comparing the pronounced word to the different memorized references and for displaying at each repetition of the word the words corresponding to the references in their order of resemblance to the pronounced word. The user is able to train the apparatus easily by repeating a word until the displayed word agrees with what he has said, the coded form of this spoken word then being stored as the reference for the corresponding word of the vocabulary.

Abstract: An electro-acoustic transducer capable of operating as an emitter and as a pick-up for acoustic waves in an ambient medium includes a cover member having an opening for communication with the ambient medium, first and second diaphragms which are spaced from each other within the cover member, the second diaphragm being capable of vibrating under the effect of acoustic waves and being disposed between the first diaphragm and the opening in the cover member, an electromagnet for causing vibrations of the first diaphragm in response to electrical excitation signals when the transducer is operating in the emitter mode, an air cushion contained in a closed chamber separating the two diaphragms or a rigid mechanical connection between the two diaphragms for communicating the vibrations of the first diaphragm to the second diaphragm, and a pair of electrodes disposed on opposite sides of the second diaphragm, which is preferably a sheet of electret, for producing an output signal in response to vibrations of the sec

Abstract: A sensitive element is described for use with a strain sensor, which has low sensitivity to temperature.The sensitive element comprises a support, preferably consisting of a thin plate, on which is secured a piezoelectric resonator preferably shaped as a double tuning-fork. The deformations of the support are transmitted to the resonator thereby modifying the frequency of resonance.

Abstract: An electronic circuit for a high impedance probe for an instrument for measuring electrical voltages, comprising an input field effect transistor 15 connected in a source-follower configuration, a bipolar transistor 17 connected in an emitter-follower configuration and controlled by the transistor 15, a current source 18 serving as a load for the transistor 17, an amplifier 19 having a gain G which is slightly less than unity, the input of the amplifier being controlled by the transistor 15, and finally a resistor 20 which serves as a load for the transistor 15 and which connects the source of the transistor 15 to the output 8 of the amplifier 19, said output also serving as the output of the circuit, which is supplied by a voltage source applied between the current source 18 and the collector of the transistor 17. By virtue of the amplifier 19, the effective load resistance seen by the transistor 15 is R.sub.20 /(1-G), R.sub.20 being the value of the resistor 20.

Abstract: A watch display comprises time display hands (3, 4) and a reflecting digital display (5) which acts as dial for the hands, the display being transparent under the effect of an electric field and opaque in the absence of the field.

Abstract: The present invention relates to a dark colored composition based on liquid crystals, especially for use in a dichroic display cell. It comprises a mixture of liquid crystals and of dyes respectively red, yellow and blue. The red dye is the 4,4'-bis(p-dimethylamino-phenylazo)-2-methyl-azobenzene; the yellow dye is the 4,4'-bis(p-methoxy-phenylazo)-2-methyl-azobenzene; and the blue dye in an anthraquinonic dye of formula (III), ##STR1## in which A is ##STR2## and B is H or ##STR3## where R and R', indentical or different, are a lower alkyl or alkoxy group, one of the A and B being H when the other is not H.