US 4,061,905 AGranted

Filter having frequency-dependent transmission properties for electric analog signals

AssigneeSiemens Aktiengesellschaft

InventorAlfred Fettweis

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Abstract

In one illustrative embodiment, a filter circuit for discrete signals is provided corresponding in filter function to an analog ladder structure containing inductive and capacitive components. The reactive components of the analog filter structure are realized in the filter circuit as one-port and two-port elements having time delay, while nonreactive components of the analog filter are realized as time-delay-free one-port and plural-port elements. Interface means connect the port elements together in a configuration corresponding to the configuration of the analog ladder structure, with sets of adder and multiplier means of the interface circuitry which couple successive sets of the port elements to each other being correlated with the connective relationship (whether series, series-parallel or parallel) between the corresponding components or branches of the analog ladder structure and with the parameters of the analog components, so that the filter circuit essentially simulates the analog ladder structure in its filter characteristics.

Claims13

Dependent claims

A filter for discrete signals,

a. said filter comprising a filter circuit operating on discrete signals and having a filter function for discrete signals corresponding to the frequency-dependent transmission properties for electric analog signals of an analog ladder structure having a predetermined configuration of interconnected analog components including at least three reactive analog components with respective impedance-representing constants;
b. said filter circuit for discrete signals having a plurality of port elements including ports each with a port input and a port output terminal, at least certain of said plurality of port elements corresponding in filter function to reactive analog components of the analog ladder structure and such certain port elements comprising time delay means interposed between port input and output terminals thereof, each time delay means providing a time delay which is a function of a given time interval and being operable for receiving an input signal from an associated input terminal at a discrete time and for supplying an output signal to an associated output terminal at a discrete time thereafter in accordance with said time delay;
the ports of said port elements being assigned port impedance numbers in accordance with the impedance-representing constants of the analog ladder structure corresponding thereto, and
c. said filter circuit comprising interface device means having interface ports connected with the ports of said port elements and interconnecting the port elements in accordance with the configuration of said analog ladder structure, and said interface ports including sets of interface ports connecting with sets of port elements corresponding to sets of connected analog components of the analog ladder structure;
d. the interface device means having interface circuitry including adder means and multiplier means connected with each of the sets of interface ports for interchange of signals with ports of the port elements connected with such interface ports, each such multiplier means having a multiplier coefficient correlated with the port impedance numbers of the respective ports of said port elements interchanging signals therewith.

2 more elements

A filter for discrete signals,

a. said filter comprising a filter circuit operating on discrete signals and having a filter function for discrete signals corresponding to the frequency-dependent transmission properties for electric analog signals of an analog filter structure having a predetermined configuration of interconnected analog components comprising at least three interconnected reactive analog components with respective impedance-representing constants;
b. said filter circuit for discrete signals having a plurality of port elements including ports each with a port input and a port output terminal, at least three of said plurality of port elements comprising reactive port elements corresponding in filter function to respective reactive analog components of the analog filter structure and such reactive port elements comprising time delay means interposed between port input and output terminals thereof, each time delay means providing a time delay which is a function of a given time interval and being operable for receiving an input signal from an associated input terminal at a discrete time and for supplying an output signal to an associated output terminal at a discrete time thereafter in accordance with said time delay;
the ports of said port elements being assigned port impedance numbers in accordance with the impedance-representing constants of the analog components corresponding thereto, and
c. said filter circuit comprising interface device means having interface ports connected with the ports of said port elements and interconnecting the port elements in accordance with the configuration of said analog filter structure, and said interface ports effectively including at least three sets of interface ports connecting with sets of port elements corresponding to sets of connected analog components of the analog filter structure;
d. the interface device means having interface circuitry including adder means and multiplier means connected with each of the sets of interface ports for interchange of signals with ports of the port elements connected with such interface ports, each such multiplier means having a multiplier coefficient correlated with the port impedance numbers of the respective ports of said port elements interchanging signals therewith.

2 more elements

Dependencies are inferred from the claim text.