The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 23, 1998
Filed:
Sep. 19, 1996
Alain Benayoun, Cagnes Sur Mer, FR;
Jean-Francois Le Pennec, Nice, FR;
Patrick Michel, La Gaude, FR;
Henri Giuliano, Vence, FR;
International Business Machines Corporation, Armonk, NY (US);
Abstract
The invention provides an impedance adapter that automaticaly switches to impedances that match network transmit/receive lines impedances (105,106) by a controlled switching of various impedances mounted serially/parallely with connected transmitter/receiver (100,101). For a high speed adapter, a balanced transmitter/receiver is required for limiting crosstalk effect due to the high transmission rate. Transmit/Receive impedance adaptation networks (102-103) are composed of serial/parallel networks of resistors and relay contacts that are switched independently by magnetic coils of an impedance switching circuit (110) and having values conformable to the various network impedances imposed by different national regulations. By using the principle of double deviation voltage technique, a measuring circuit (108) detects upward and downward voltages (VA,VB), VB amplified by 2 to generate an analog signal VS (VS=VA-2VB) to a control logic circuit (109). This circuit (109) determines if the resistors value selected by the magnetic coils of said impedance switching circuit (110) is equal or not equal to the impedance of the network lines (106,105). Thus, it compares VS to a voltage Vref (25) to generate an output which selects and activates the correct magnetic coil for changing or keeping equal the resistors of the receive/transmit impedance network (102,103) currently connected to the network lines (105,106).