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33 records (took 0.028 seconds)

    22.
    发明专利
    未知

    公开(公告)号：IT1159706B

    公开(公告)日：1987-03-04

    申请号：IT6826978

    申请日：1978-06-02

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： MELINDO FLAVIO

    IPC: H04Q3/72 ,  H04M19/00 ,  H04M

    Abstract: The two talking wires of a line loop extending from a subscriber station to a central office, provided with respective blocking capacitors, are connected on the subscriber side of these blocking capacitors to respective signal detectors fed from a common battery and cross-coupled by a common compensating capacitor. The two signal detectors receive outgoing signals from the central-office equipment via a common photoelectric coupler and transmit incoming signals to that equipment by way of respective bistable threshold comparators and individal photoelectric couplers. The two signal detectors with their threshold comparators are constituted in integrated circuity by mutually complementary transistors and diodes together with associated resistors.

    23.
    发明专利
    未知

    公开(公告)号：IT1155661B

    公开(公告)日：1987-01-28

    申请号：IT6737182

    申请日：1982-03-24

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： MELINDO FLAVIO ,  SARTORI MARIO

    IPC: H04M3/02 ,  H04M19/02 ,  H04M

    Abstract: An electronic circuit apt to detect the lifting of a telephone handset in presence of ringing current, which is capable of detecting small variations of the d.c. current flowing through the line loop in presence of high a.c. current.It carries out the multiplication of the line current by a constant value and by a pulse signal with suitable frequency and pulse duration; it integrates said current over one or more periods of the ringing signal and compares it with pre-determined thresholds.This circuit allows the use of a single low-value capacitor and is easy-to-integrate.

    24.
    发明专利
    未知

    公开(公告)号：IT1128374B

    公开(公告)日：1986-05-28

    申请号：IT6725280

    申请日：1980-02-19

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： MELINDO FLAVIO

    IPC: H04M3/02 ,  H04M19/02 ,  H04M

    Abstract: A circuit arrangement for emitting ringing signals to a subscriber station in response to a call signal electronically generated at a telephone exchange comprises a control unit which, in the presence of such call signal, intermittently reverses a switching relay normally connecting the talking conductors of the subscriber line to monitoring equipment of the exchange whereby these conductors periodically receive a high-voltage ringing current, e.g. of 25 Hz, from a local oscillator in series with a d-c supply. The direct current is blocked by a line-terminating capacitor until the called subscriber lifts the receiver off the hook to close the line loop. If this occurs while the line is connected to the oscillator, a sensor in the control unit detects a significant disparity between the durations of the positive and negative voltage swings in an oscillator cycle and causes the release of the switching relay when that disparity exceeds a dynamic threshold determined by the actual cycle length.

    26.
    发明专利
    未知

    公开(公告)号：IT8267371D0

    公开(公告)日：1982-03-24

    申请号：IT6737182

    申请日：1982-03-24

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： MELINDO FLAVIO ,  SARTORI MARIO

    IPC: H04M3/02 ,  H04M19/02 ,  H04M

    Abstract: An electronic circuit apt to detect the lifting of a telephone handset in presence of ringing current, which is capable of detecting small variations of the d.c. current flowing through the line loop in presence of high a.c. current.It carries out the multiplication of the line current by a constant value and by a pulse signal with suitable frequency and pulse duration; it integrates said current over one or more periods of the ringing signal and compares it with pre-determined thresholds.This circuit allows the use of a single low-value capacitor and is easy-to-integrate.

    27.
    发明专利
    未知

    公开(公告)号：IT8067252D0

    公开(公告)日：1980-02-19

    申请号：IT6725280

    申请日：1980-02-19

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： MELINDO FLAVIO

    IPC: H04M3/02 ,  H04M19/02 ,  H04M

    Abstract: A circuit arrangement for emitting ringing signals to a subscriber station in response to a call signal electronically generated at a telephone exchange comprises a control unit which, in the presence of such call signal, intermittently reverses a switching relay normally connecting the talking conductors of the subscriber line to monitoring equipment of the exchange whereby these conductors periodically receive a high-voltage ringing current, e.g. of 25 Hz, from a local oscillator in series with a d-c supply. The direct current is blocked by a line-terminating capacitor until the called subscriber lifts the receiver off the hook to close the line loop. If this occurs while the line is connected to the oscillator, a sensor in the control unit detects a significant disparity between the durations of the positive and negative voltage swings in an oscillator cycle and causes the release of the switching relay when that disparity exceeds a dynamic threshold determined by the actual cycle length.

    28.
    发明专利
    未知

    公开(公告)号：DE2922271A1

    公开(公告)日：1979-12-06

    申请号：DE2922271

    申请日：1979-05-31

    Applicant: CSELT CENTRO STUDI LAB TELECOM

    Inventor： MELINDO FLAVIO

    IPC: H04Q3/72 ,  H04M19/00

    Abstract: The two talking wires of a line loop extending from a subscriber station to a central office, provided with respective blocking capacitors, are connected on the subscriber side of these blocking capacitors to respective signal detectors fed from a common battery and cross-coupled by a common compensating capacitor. The two signal detectors receive outgoing signals from the central-office equipment via a common photoelectric coupler and transmit incoming signals to that equipment by way of respective bistable threshold comparators and individal photoelectric couplers. The two signal detectors with their threshold comparators are constituted in integrated circuity by mutually complementary transistors and diodes together with associated resistors.

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