FILTER CIRCUIT

• US 20110010749A1
• Filed: 07/10/2009
• Published: 01/13/2011
• Est. Priority Date: 07/10/2009
• Status: Active Grant

• Current Assignee: PPC Broadband Incorporated (Belden Inc.)
• Original Assignee: John Mezzalingua Associates Incorporated
• Inventors: Alkan, Erdogan
• Granted Patent: US 8,125,299 B2
• Time in Patent Office: Days
• US Class Current: 725/127
• CPC Class Codes: H03H 1/00 Constructional details of impedance networks whose electrical mode of operation is not specified or applicable to more than one type of network constructional details of electromechanical transducers H03H9/00
• CPC Class Codes: H03H 7/01 Frequency selective two-port networks
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence
• CPC Class Codes: H03H 7/1766 Parallel LC in series path H03H7/1783 takes precedence
• CPC Class Codes: H04N 7/102 Circuits therefor, e.g. noise reducers, equalisers, amplifiers H04N7/108 takes precedence
• CPC Class Codes: H05K 1/0231 Capacitors or dielectric substances
• CPC Class Codes: H05K 1/0233 Filters, inductors or a magnetic substance
• CPC Class Codes: H05K 1/0254 High voltage adaptations; Electrical insulation details; Overvoltage or electrostatic discharge protection electrostatic discharge protection for electric apparatus in general H05K9/0067, H05K9/0079; Arrangements for regulating voltages or for using plural voltages
• CPC Class Codes: H05K 1/0259 Electrostatic discharge [ESD] protection
• CPC Class Codes: H05K 1/026 Spark gaps
• CPC Class Codes: H05K 1/165 incorporating printed inductors
• CPC Class Codes: H05K 2201/09181 Notches in edge pads

Abstract

A filter for use in a coaxial cable network includes a printed circuit board having first and second opposed major surfaces, and first and second opposing sides. The opposed major surfaces are substantially parallel to a single plane, and are bisected by a longitudinal axis. The first and second opposing sides are substantially parallel to the longitudinal axis. The filter further includes an input terminal and an output terminal connected to the printed circuit board. The input terminal and the output terminal have an axis extending substantially parallel to the longitudinal axis. A signal path is disposed on the printed circuit board and extends from the input terminal toward the output terminal. The filter further includes a plurality of resonator elements fabricated upon the first opposed major surface. In one embodiment, the inductor elements are arranged in series along the signal path defining a footprint of less than 540 square millimeters. The filter passes a first range of frequencies in a provider bandwidth and attenuates a second range of frequencies in a personal data network bandwidth. In one embodiment, the resonator elements are parallel inductor elements and capacitor elements, the inductor elements being etched spiral inductors.

Claims

1. A filter circuit assembly comprising:

a printed circuit board having first and second opposed major surfaces and first and second opposing sides, the opposed major surfaces being substantially parallel to a single plane and being bisected by a longitudinal axis, the first and second opposing sides being substantially parallel to the longitudinal axis;

an input terminal connected to the printed circuit board, the input terminal having an axis extending substantially parallel to the longitudinal axis;

an output terminal connected to the printed circuit board, the output terminal having an axis extending substantially parallel to the longitudinal axis;

a signal path disposed on the printed circuit board, the signal path extending from the input terminal toward the output terminal;

a plurality of resonator elements being fabricated upon at least one of the major surfaces, the resonator elements arranged in series along the signal path and defining a footprint being less than 540 square millimeters; and

wherein the filter passes a first range of frequencies in a provider bandwidth and attenuates a second range of frequencies in a personal data network bandwidth.

2. The filter circuit assembly of claim 1, wherein the first range of frequencies in the provider bandwidth is between 5 megahertz and 1002 megahertz, and the second range of frequencies in the personal data network bandwidth is between 1125 megahertz and 1525 megahertz.

3. The filter circuit assembly of claim 1, wherein the filter has an insertion loss characteristic of more than 30 decibels in the personal data network bandwidth.

4. The filter circuit assembly of claim 1, wherein the filter has an insertion loss of less than 3 decibels in the provider bandwidth.

5. The filter circuit assembly of claim 1, further comprising a spark gap element disposed on one of the major opposing surfaces.

6. The filter circuit assembly of claim 1 wherein the resonator elements comprise parallel inductor and capacitor elements.

7. The filter circuit assembly of claim 6 wherein the inductor elements are disposed on one major surface and the capacitor elements are disposed on another major surface, the inductor elements and capacitor elements being in electrical communication by a via.

8. The filter circuit assembly of claim 6 wherein the inductor elements are spiral etched inductor elements.

9. The filter circuit assembly of claim 8 further comprising a tuning element bridging an intermediate portion of at least one of the spiral etched inductor elements to a via.

10. The filter circuit assembly of claim 6 further comprising a tuning element bridging an intermediate portion of at least one of the inductor elements to the signal path.

11. The filter circuit assembly of claim 1 wherein the footprint is less than 250 square millimeters.

12. The filter circuit assembly of claim 11 wherein the footprint is less than 190 square millimeters.

13. A filter circuit having a frequency response, the frequency response comprising:

a signal path extending from an input to an output and having a conductor and a ground;

a pass portion having a first frequency spectrum in a provider bandwidth;

an attenuated portion having a second frequency spectrum in a personal data network bandwidth, the attenuated portion causing a uniform insertion loss of greater than 30 decibels;

a transition portion between the low pass portion and the attenuated portion; and

wherein a topology of the filter circuit comprises a first plurality of resonator elements arranged in series along the signal path, and a second plurality of shunt capacitor elements disposed between the resonator elements, the second plurality of shunt capacitor elements in electrical communication with the ground.

14. The filter circuit of claim 13 wherein the frequency range in the provider bandwidth is 5 megahertz to 1002 megahertz.

15. The filter circuit of claim 13 wherein the range of frequencies in the personal data network bandwidth is 1125 megahertz to 1525 megahertz.

16. The filter circuit of claim 15 wherein the frequency range in the personal data network bandwidth is greater than 1125 megahertz and less than 1525 megahertz.

17. The filter circuit of claim 16 wherein the attenuated portion causing a uniform insertion loss of greater than 40 decibels.

18. The filter circuit of claim 13 wherein the attenuated portion causes a uniform insertion loss of greater than 50 decibels.

19. The filter circuit of claim 13 wherein the resonator elements comprise parallel inductor elements and capacitor elements.

20. The filter circuit of claim 13 wherein the topology is an elliptic filter.

21. The filter circuit of claim 20 wherein the elliptic filter is a Chebyshev elliptic filter.

22. The filter circuit of claim 21 wherein the elliptic filter is a ninth order Chebyshev elliptic filter.

23. The filter circuit of claim 13 wherein the transition portion has a frequency range of less than 150 megahertz.

24. A filter circuit assembly for use in television provider services, the circuit assembly comprising:

a printed circuit board having first and second opposed major surfaces and first and second opposing sides, the opposed major surfaces being substantially parallel to a single plane and being bisected by a longitudinal axis, the first and second opposing sides being substantially parallel to the longitudinal axis, the printed circuit board being comprised of a substrate having dielectric properties;

a signal path disposed on the substrate, the signal path extending from an input port toward an output port;

at least three etched spiral inductor elements fabricated upon the first opposed major surface and arranged in series along the signal path, the arrangement of the inductor elements defining a footprint, the footprint being less than 250 square millimeters;

a plurality of capacitor elements in electrical communication with the etched inductor elements to form a plurality of resonator elements, the capacitor elements being fabricated upon the second opposed major surface and being connected to the inductor elements by a via; and

wherein the filter passes a first range of frequencies between 5 megahertz and 1002 megahertz and attenuates a second range of frequencies between 1125 megahertz and 1525 megahertz, the second range of frequencies having an insertion loss of more than 30 decibels.

25. The filter circuit assembly of claim 24 wherein the footprint is less than 190 square millimeters.

26. The filter circuit assembly of claim 24 wherein the inductor element comprises a conductive trace, the filter further comprising a tuning element bridging intermediate portions of the conductive trace to the via.

27. The filter circuit assembly of claim 26 wherein the tuning element is a conductive trace etched into the opposed major surface.

28. A coaxial cable ground block assembly comprising:

a housing having a thru bore, the housing adapted for electrical contact with a source to electrical ground;

a first connector body coupled to one end of the thru bore of the housing;

a first coaxial cable terminal coupled to the first connector body;

a second connector body coupled to the other end of the thru bore of the housing;

a second coaxial cable terminal coupled to the second connector body; and

a printed circuit board sealed within the housing, the circuit board having an input in electrical contact with the first terminal, an output in electrical contact with the second terminal, a ground plane in electrical contact with the housing, a signal path extending from the input toward the output, and a filter circuit disposed on the signal path, the filter circuit passing a provider bandwidth and attenuating a personal data network bandwidth.

29. The ground block assembly of claim 28 wherein the filter circuit comprises a plurality of resonator elements arranged in series along the signal path.

30. The ground block assembly of claim 29 wherein the resonator elements define a footprint being less than 540 square millimeters.

31. The connector assembly of claim 30 wherein the footprint is less than 250 square millimeters.

32. The connector assembly of claim 31 wherein the footprint is less than 190 square millimeters.

33. The connector assembly of claim 29 wherein the resonator elements comprise parallel inductor and capacitor elements, the inductor elements comprising spiral etched inductor elements.

34. A coaxial cable connector assembly comprising:

a printed circuit board having a signal path and a ground plane thereon, the printed circuit board having first and second opposed major surfaces and first and second opposing sides, the opposed major surfaces being substantially parallel to a single plane and being bisected by a longitudinal axis, the first and second opposing sides being substantially parallel to the longitudinal axis, the signal path having an input, an output, and a filter circuit disposed therebetween, the filter circuit passing a provider bandwidth and attenuating a personal data network bandwidth, the filter circuit having a plurality of resonator elements arranged in series along the signal path and defining a footprint being less than 540 square millimeters;

a body that receives the printed circuit board, the body having a first end and a second end opposite the first end, the first end and second end shaped so as to receive a first cable connector and a second cable connector respectively;

a first terminal disposed within the body in electrical contact with the input of the signal path;

a second terminal disposed within the body in electrical contact with the output of the signal path;

a first insulator disposed in surrounding relation to the first terminal;

a second insulator disposed in surrounding relation to the second terminal; and

at least one seal located entirely within the body to protect the circuit board from environmental elements.

35. The connector assembly of claim 34 wherein the footprint is less than 250 square millimeters.

36. The connector assembly of claim 35 wherein the footprint is less than 190 square millimeters.

37. The connector assembly of claim 34 wherein the filter circuit has an insertion loss characteristic of more than 30 decibels in the personal data network bandwidth.

38. The connector assembly of claim 34 wherein the resonator elements comprise parallel inductor and capacitor elements, the inductor elements comprising spiral etched inductor elements.