Method and apparatus for dual notch ripple filtering

Patent metadata

Field	Value
Publication number	US-9893705-B2
Application number	US-201414587443-A
Country	US
Kind code	B2
Filing date	Dec 31, 2014
Priority date	Dec 31, 2014
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

An apparatus includes a self-coupled transformer, a first band stop filter and a tank circuit connected in series with the first band stop filter between first and second windings of the self-coupled transformer. An inductor of the tank circuit acts as an out-of-phase third winding of the self-coupled transformer.

First claim

What is claimed is:

1. An apparatus comprising:
a self-coupled transformer;
a band stop filter; and
a tank circuit connected in series with the band stop filter between first and second windings of the self-coupled transformer;
wherein an inductor of the tank circuit acts as an out-of-phase third winding of the self-coupled transformer, and
the band stop filter is defined in part by the inductor.

2. The apparatus of claim 1 wherein the apparatus provides a dual notch ripple cancellation filter across the self-coupled transformer.

3. The apparatus of claim 2 , further comprising:
a load ladder of resistors and capacitors connected in parallel across the out-of-phase third winding and the band stop filter;
wherein the load ladder is tapped for high, low, and center outputs.

4. The apparatus of claim 3 wherein capacitances of the capacitors of the load ladder are less than capacitances of additional capacitors of the band-stop filter and the tank circuit.

5. The apparatus of claim 2 wherein the first and second windings have an inductance smaller than an inductance of the band stop filter.

6. The apparatus of claim 2 wherein the out-of-phase third winding of the self-coupled transformer has an inductance larger than an inductance of the first and second windings.

7. The apparatus of claim 2 wherein the out-of-phase third winding of the self-coupled transformer has an inductance smaller than an inductance of the first and second windings.

8. The apparatus of claim 2 wherein the out-of-phase third winding of the self-coupled transformer has an inductance larger than an inductance of the band stop filter.

9. The apparatus of claim 2 wherein the out-of-phase third winding of the self-coupled transformer has an inductance smaller than an inductance of the band stop filter.

10. The apparatus of claim 2 wherein the first and second windings have an inductance larger than an inductance of the band stop filter.

11. The apparatus of claim 1 further comprising at least one additional band stop filter connected in parallel with the band stop filter.

12. An apparatus comprising:
a self-coupled transformer;
a band stop filter;
a tank circuit connected in series with the band stop filter between first and second windings of the self-coupled transformer; and
wherein an inductor of the tank circuit acts as an out-of-phase third winding of the self-coupled transformer,
the apparatus further comprises a load ladder of resistors and capacitors connected in parallel across the out-of-phase third winding and the band stop filter,
the apparatus provides a dual notch ripple cancellation filter across the self-coupled transformer, and
the load ladder is tapped for high, low, and center outputs.

13. The apparatus of claim 12 , wherein capacitances of the capacitors of the load ladder are less than capacitances of additional capacitors of the band-stop filter and the tank circuit.

Assignees

• Gen Electric

Inventors

• Freeman Melissa Jean
• Mcfarland Thomas George
• Wiza Margaret Ann
• Link Douglas

Classifications

• H03H7/09 Primary

  Filters comprising mutual inductance · CPC title

• H03H7/06 Primary

  including resistors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence) · CPC title

• H03H7/075

  Ladder networks, e.g. electric wave filters · CPC title

• H03H2007/013

  Notch or bandstop filters · CPC title

• H03H7/01 Primary

  Frequency selective two-port networks · CPC title