Multiplexing and demultiplexing of narrowband and broadband services in a transmission connection
View Patent ↗The invention relates to the implementation of narrowband and broadband services in a telecommunications network. A splitter element is connected to a transmission link, the splitter element comprising a passive low-pass filter block connected between the transmission link and a first interface, a high-pass filter unit connected between the transmission link and a second interface, and discrete impedance converting means for adapting the first interface to the characteristic impedance of the transmission link. In order that the impedance matching required by the low-pass filter block may be implemented in an economical way yet maintaining the service quality, the impedance converting means are entirely placed between the interface of the low-pass filter block on the transmission link side and the first interface.
1. A method for implementing narrowband and broadband services on a transmission link of a telecommunications network, the method comprising the steps of:
transferring signals belonging to a narrowband service in a first frequency range below a given threshold frequency and signals belonging to a broadband service in a second frequency range above said threshold frequency in the transmission link;
separating signals relating to the narrowband service in a passive low-pass filter block connected between the transmission link and a single discrete active impedance converting means;
receiving the signals relating to the narrowband service from the passive low-pass filter block in the discrete active impedance converting means, said discrete active impedance converting means located entirely between the passive low-pass filter block and a first interface;
matching impedance of the first interface to a characteristic impedance of the transmission link in said discrete active impedance converting means, wherein matching is conducted without external control entirely after the step of separating the signals relating to the narrowband service; and
separating signals relating to a broadband service in a high-pass filter unit connected between the transmission link and a second interface.
2. A splitter element in a telecommunications system for separating signals transferred in different frequency ranges, said splitter element comprising:
a line port connected to a transmission link, the transmission link configured to transfer signals belonging to a narrowband service in a first frequency range below a given threshold frequency and signals belonging to a broadband service in a second frequency range above said threshold frequency;
a passive low-pass filter block connected between the line port and a discrete active impedance converting means and configured to separate signals relating to the narrowband service;
the discrete active impedance converting means for adapting a first interface to a characteristic impedance of the transmission link, said first interface being intended for signals relating to narrowband service, wherein the discrete active impedance converting means locates entirely between the passive low-pass filter block and the first interface and is configured to conduct the adapting without external control entirely after separating the signals relating to narrowband service in the passive low-pass filter block; and
a high-pass filter connected between the line port and a second interface and configured to separate signals relating to the broadband service, said second interface being intended for signals transferred in a higher frequency range.