-
公开(公告)号：DE2811388A1
公开(公告)日：1978-10-05
申请号：DE2811388
申请日：1978-03-16
Applicant: IBM
Inventor： GRANGE JEAN-CLAUDE , HERNANDEZ PHLIPPE , REYNES DANIEL F , SUZZONI JEAN-PIERRE L , TU NGHIEM HO
Abstract: A circuit associated with a telephone line to detect line status includes a first detector sensitive to the line current phase, a second detector sensitive to the ringing voltage phase, and two pulse generators of the same frequency as the ringing voltage, appearing at the positive and negative zero-crossings of the ringing voltage, respectively. When only the ringing current is applied to the line, only the signals from both detectors and one generator are simultaneously present (once per period). When the called subscriber lifts his handset, the signals from both detectors and the other generator are also simultaneously present once per period. These pulse coincidences are detected and processed by an appropriate logic.
-
公开(公告)号：CA1111517A
公开(公告)日：1981-10-27
申请号：CA282254
申请日：1977-07-07
Applicant: IBM
Inventor： FERRY MICHEL F , REYNES DANIEL F
IPC: H03K17/60
Abstract: An inductive load driving amplifier is disclosed which includes two serially connected transistors, with Zener diodes limiting the collector-emitter voltage of the one and diverting the collector-base current of the other when the first one switches off. The driver is implemented as an integrated circuit. This collector isolation constitutes a high voltage Zener diode which contributes to limit the collector voltages. The combination of these features prevents the device from being exposed to second breakdown when switching highly inductive loads (e.g. several Henrys under SOV), thereby avoiding the harmful effects of breakdowns during switching.
-
公开(公告)号：AU3219578A
公开(公告)日：1979-07-12
申请号：AU3219578
申请日：1978-01-05
Applicant: IBM
Inventor： GRANGE JEAN-CLAUDE C , HERNANDEZ PHILIPPE , REYNES DANIEL F , SUZZONI JEAN-PIERRE L , TU NGHIEM HO
-
-
Search Results
3
records
(took 0.016 seconds)
