Telephonic communications – Subscriber line or transmission line interface
Patent
1994-03-14
1996-03-05
Matar, Ahmad F.
Telephonic communications
Subscriber line or transmission line interface
379345, 333175, 333176, H04M 700
Patent
active
054974178
ABSTRACT:
A switching device is presented for the transmission of telecommunication signals between a telephone network exchange and at least one subscriber connected thereto, where the exchange is able to transmit metering pulses, in addition to the voice signal. The signals are transmitted as digital signals between the exchange and the subscriber via a two-wire line, Which is connected with the exchange through a hybrid switching unit. To prevent the metering pulses from interfering with the voice signals, a parallel resonant circuit consisting of an inductance and a capacitor is connected to the two-wire system of the hybrid switching unit, and the receiving branch of the hybrid switching unit has an active and a passive filter connected in series. The passive filter is adjusted for the metering pulse frequency, and a filter that is tuned to the passive filter is used as the active filter, which compensates for a decrease in the NF (low frequency) level caused by the passive filter, with a corresponding increase.
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Brahms Martin
Fritz Wolfgang
Klamt Werner
ke Kommunikations-Elektronik GmbH & Co.
Matar Ahmad F.
Weaver Scott L.
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