PHASE MATCHING BAND-PASS FILTER USING EXPONENTIAL FUNCTION APPROXIMATION

• US 20110291751A1
• Filed: 01/22/2010
• Published: 12/01/2011
• Est. Priority Date: 01/22/2009
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yoon, Byung Tae, Son, Mi Hyun, Park, Han Gue, Lee, Jae Sub, Zeong, Jong Wook
• Granted Patent: US 8,508,292 B2
• Time in Patent Office: Days
• US Class Current: 327/557
• CPC Class Codes: H03H 11/48 simulating reactances
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence

Abstract

A The present invention relates to a phase matching band-pass filter using exponential function approximation, comprising an inductor including a parasitic resistor, a first device wherein a first amplifier is connected in a feedback mode, a capacitor including a parasitic resistor, a plurality of filter devices including a second device that is connected with a second amplifier in a feedback mode, and a coupling capacitor that connects the plurality of filter devices; the impedance of the first device has an increasing exponential function relation with a frequency, impedance of the second device has a decreasing exponential function relation with the frequency, and the first device is connected with the second device in parallel. According to the phase matching band-pass filter using exponential function approximation of this invention, conventional inductors and capacitors can be used 0 without modification or use of negative resistance, resulting in a high-performance phase matching band-pass filter. In addition, when a device with impedance characteristics that approximate an exponential function is used, the degree of frequency selection 0 becomes higher than that of conventional filters resulting in filters having high Q values and stability, such as channel selection filters.

Claims

1. A filter device comprising:

a first device to which an inductor L having parasitic resistance R₁ and a first amplifier are feedback-connected; and

a second device to which a capacitor C having parasitic resistance R₂ and a second amplifier are feedback-connected,

wherein the impedance of the first device has a relation of an increase exponential function to frequency , the impedance of the second device has a relation of a decrease exponential function to frequency, and the first and second devices are connected in parallel.

2. The filter device of claim 1, wherein the first amplifier has a gain of

3. The filter device of claim 2, wherein the first device has impedance of

4. The filter device of claim 1, wherein the second amplifier has a gain of

5. The filter device of claim 4, wherein the second device has impedance of

6. A filter device comprising:

a first device to which an inductor L having parasitic resistance R₁ and a first amplifier are feedback-connected; and

a second device,

wherein the impedance of the first device has a relation of an increase exponential function to frequency , the first and second device are connected in parallel, and combined impedance of the first and second devices becomes infinite at a predetermined frequency.

7. A filter device comprising:

a first device to which an inductor L having parasitic resistance R₁ and a first amplifier are feedback-connected; and

a second device,

wherein the impedance of the first device has a relation of a decrease exponential function to frequency , the first and second devices are connected in parallel, and combined impedance of the first and second devices becomes infinite at a predetermined frequency.

8. A band-pass filter comprising:

a plurality of filter devices including a first device to which an inductor L having parasitic resistance R₁ and a first amplifier are feedback-connected and a second device to which a capacitor C having parasitic resistance R₂ and a second amplifier are feedback-connected; and

a coupling capacity connecting the filter devices to each other,

wherein the impedance of the first device has a relation of an increase exponential function to frequency , the impedance of the second device has a relation of a decrease exponential function to frequency, and the first and second devices are connected in parallel.

9. The band-pass filter of claim 8, wherein the first amplifier has a gain of

10. The band-pass filter of claim 9, wherein the first device has impedance of

11. The band-pass filter of claim 8, wherein the second amplifier has a gain of

12. The band-pass filter of claim 11, wherein the second device has impedance of

13. A band-pass filter comprising:

a plurality of filter devices including a first device to which an inductor L having parasitic resistance R₁ and a first amplifier are feedback-connected and a second device; and

a coupling capacitor Connecting the filter devices to each other,

wherein the impedance of the first device has a relation of an increase exponential function to frequency , the first and second devices are connected in parallel, and combined impedance of the first and second devices becomes infinite at a predetermined frequency.

14. A band-pass filter comprising:

a plurality of filter devices including a first device to which an inductor L having parasitic resistance R₁ and a first amplifier are feedback-connected and a second device; and

a coupling capacitor Connecting the filter devices to each other,

wherein the impedance of the first device has a relation of a decrease exponential function to frequency , the first and second devices are connected in parallel, and combined impedance of the first and second devices becomes infinite at a predetermined frequency.