Abstract: The invention relates to electronic circuits for measuring, by synchronous detection, weak signals whose reference level is not well known and is subject to large fluctuations. A first correlated double sampling is performed between a time T1 situated just before the start of the measurement pulse and a time T2 situated just before the end of the measurement pulse; subsequently, a second correlated double sampling is performed between time T2 and a time T3 situated after the end of the measurement pulse. Finally, the difference between signal levels coming from the two measurements is taken, this difference being a representation of the signal value Vm considered with respect to a reference level that is intermediate between the reference levels at times T1 and T3.

Abstract: The invention relates to a photographing device whose bulk is intended to be reduced. According to the invention, a permanent division of the object field observed by the device is associated with a catadioptric configuration.

Abstract: The invention relates to matrix image sensors intended in particular for digital photography. The invention provides a driver in each pixel that allows exposure control common to the entire matrix. The driver comprises five transistors, a photodiode and, apart from a supply conductor and a ground, four control conductors, these being an exposure control conductor common to all the pixels of the matrix; a row selection conductor common to all the pixels of any one row; a reset conductor common to all the pixels of any one row; and a column conductor for collecting the signal read on the pixels during row-by-row reading of the charges photogenerated in the pixels of the matrix.

Abstract: The invention proposes an image sensor comprising a picture capture matrix having N rows and K columns of image dots, a read register at the free end of the K columns. In order to improve the read speed of the matrix, the invention proposes that the horizontal transfer into the read register be continued even while the vertical signals for shifting from one row to the other are operative, without however continuing the horizontal transfer while the transfer gate between columns and horizontal register is open. The unloading time of the horizontal read register therefore overlaps the time reserved for each vertical transfer step, instead of these times being added together. The gain in time, being repeated for each row, will be all the more significant the higher the number of rows. Means are provided for limiting the effect of the column transfer switching operations on the reading of the charges at the output of the read register.

Abstract: The invention relates to small dimension image recorders, such as an image recorder, comprising a matrix of rows and columns of photosensitive points, arranged on a chip of a generally square or rectangular form with believed corners, characterised in comprising a reading register arranged at the base of the matrix. The register is bent to follow the bevelled corners of the chip and thus comprises a horizontal piece and two oblique pieces. The sensor further comprises means (ZIn) to direct the photosensitive charges form the columns terminating opposite the beveled corners towards the stage of the reister situated in the oblique part along the beveled corners. The above is of application to intraoral dental radiological sensors.

Abstract: The invention pertains to a comparison circuit for an analog/digital converter. In order to reduce the effect of the offset voltages of the various comparators of the comparison circuit, voltage followers and a resistor network delivering at its outputs, mean voltages that are the average of those present on outputs of the comparators are linked downstream of the outputs of the comparators.

Abstract: The invention relates to integrated electronic circuits, and notably to those comprising analog functions. The invention relates more particularly to a starter circuit designed to ensure the automatic start-up of a biasing circuit following an interruption in the operation of the latter.

Abstract: The invention relates to integrated electronic circuits, and notably to those comprising analog functions. The invention relates more particularly to a starter circuit designed to ensure the automatic start-up of a biasing circuit following an interruption in the operation of the latter.

Abstract: The invention relates to matrix image sensors intended in particular for digital photography. The invention provides a driver in each pixel that allows exposure control common to the entire matrix. The driver comprises five transistors, a photodiode and, apart from a supply conductor and a ground, four control conductors, these being an exposure control conductor common to all the pixels of the matrix; a row selection conductor common to all the pixels of any one row; a reset conductor common to all the pixels of any one row; and a column conductor for collecting the signal read on the pixels during row-by-row reading of the charges photogenerated in the pixels of the matrix.

Abstract: The invention relates to small dimension image recorders, such as an image recorder, comprising a matrix of rows and columns of photosensitive points, arranged on a chip of a generally square or rectangular form with believed corners, characterised in comprising a reading register arranged at the base of the matrix. The register is bent to follow the bevelled corners of the chip and thus comprises a horizontal piece and two oblique pieces. The sensor further comprises means (ZIn) to direct the photosensitive charges form the columns terminating opposite the beveled corners towards the stage of the reister situated in the oblique part along the beveled corners. The above is of application to intraoral dental radiological sensors.

Abstract: The invention proposes an image sensor comprising a picture capture matrix having N rows and K columns of image dots, a read register at the free end of the K columns. In order to improve the read speed of the matrix, the invention proposes that the horizontal transfer into the read register be continued even while the vertical signals for shifting from one row to the other are operative, without however continuing the horizontal transfer while the transfer gate between columns and horizontal register is open. The unloading time of the horizontal read register therefore overlaps the time reserved for each vertical transfer step, instead of these times being added together. The gain in time, being repeated for each row, will be all the more significant the higher the number of rows. Means are provided for limiting the effect of the column transfer switching operations on the reading of the charges at the output of the read register.

Abstract: In digital signal demodulation and detection circuits, especially digital radio signal reception and processing circuits, the signals are received in analog form and have to be converted into logic levels. This is done in practice by comparing the level of the signal with its mean level. The mean level is established by an RC lowpass filter which introduces an inconvenient delay into the preparation of the mean level. The mean level of the signal, established by an RC filter is compared and applied to an input B of a comparator COMP, at the level of the analog signal delayed by a phase-shifter and applied to another input A of the comparator. In order that the delay introduced by the phase-shifter into the analog signal may be substantially the same as the delay given to the mean value by the RC circuit, the phase-shifter is made with the same RC circuit and an amplifier mounted so as to set up a phase shift transfer function of the (1−RCp)/(1+RCp) type where p is the Laplace variable.