H - Electricity – 04 – M
Patent
H - Electricity
04
M
379/63
H04M 19/00 (2006.01)
Patent
CA 1260170
ABSTRACT OF THE DISCLOSURE A balanced type subscriber line interface circuit capable of being fabricated at least partly in a monolithic IC is described. The battery feed circuit comprises three pairs of mirror circuits connected to each other so as to eliminate longitudinal noise and noise induced in the voltage source. Overcurrent protection is achieved by varying the mirror ratio of current feeding mirror circuits when the subscriber line current exceeds a threshold value. A 2- to 4-wire converter has its frequency characteristics compensated by feeding back a current with an impedance network composed of two impedance elements each having respectively an impedance N time as high as that of the load impedance and the termination impedance. The turn around signal in the output signal of the 4-wire system is canceled by mixing a signal opposite in phase to that of the 4-wire input signal. The supervising circuit provides scan signals detecting the currents running through the subscriber line, and discriminating the states of the sub- scriber lines. The circuit is provided with a ground separation circuit to separate the grounds of high voltage source and low voltage source. The separation is done by feeding a current having a same amplitude but opposite phase to that of the signal current transferred from the receiving system to the sending system having a different ground.
516222
Ayano Mitsutoshi
Iketani Yozo
Shibuya Kiyoshi
Takato Kenji
Tojo Toshiro
Fetherstonhaugh & Co.
Fujitsu Limited
LandOfFree
Subscriber line interface circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Subscriber line interface circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Subscriber line interface circuit will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1285896