METHODS, SYSTEMS, AND NON-TRANSITORY COMPUTER READABLE MEDIA FOR WIDEBAND FREQUENCY AND BANDWIDTH TUNABLE FILTERING

• US 20160087659A1
• Filed: 10/29/2015
• Published: 03/24/2016
• Est. Priority Date: 08/30/2010
• Status: Active Grant

• Current Assignee: Archaius, Inc.
• Original Assignee: Physical Devices, LLC
• Inventors: Vosburgh, Frederick, Wilson, Charley Theodore III, Wilkerson, Jonathan Ryan
• Granted Patent: US 9,450,625 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 1/1018 noise filters connected between the power supply and the receiver suppression or limitation of noise from electric apparatus H04B15/00; demodulation H03D; ripple filters H02M1/14; filters in general 95G, H03H; power supplies H04B1/1607
• CPC Class Codes: H04B 1/1081 Reduction of multipath noise by equalising H04B7/005
• CPC Class Codes: H04B 1/44 Transmit/receive switching
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 7/0894 using different delays between antennas

Abstract

Methods, systems, and computer readable media for wideband frequency and bandwidth tunable filtering are disclosed. According to one aspect, the subject matter described herein includes a wideband frequency and bandwidth tunable filter that splits a filter input signal into first and second input signals, modifies the first input signal to produce a first output signal, modifies the second input signal to produce a second output signal having an intermediate frequency response, and combines the first and second output signals while adjusting their relative phases and/or amplitudes to produce a filter output signal with the target frequency response. Adjustment includes splitting the second input signal into third and fourth input signals, which are modified and then combined to produce the second output signal having the intermediate frequency response.

Claims

1. A method for wideband frequency and bandwidth tunable filtering, the method comprising:

receiving an input signal for which wideband frequency and bandwidth tunable filtering is desired;

creating a second input signal having at least one of a desired phase, amplitude, and delay relative to the first input signal;

modifying the second input signal to create a modified second input signal having a desired frequency spectrum, wherein creating the modified second input signal having the desired frequency spectrum includes creating a third input signal having at least one of a desired phase, amplitude, and delay relative to the second input signal, modifying the third input signal to produce a fourth input signal, and combining the second input signal and the fourth input signal to create the modified second input signal having the desired frequency spectrum;

adjusting at least one of phase, delay, amplitude magnitude, amplitude sign, and frequency spectrum of the modified second input signal with respect to the first input signal; and

combining the modified second input signal with the first input signal to create an output signal having the desired frequency response.

2. The method of claim 1 wherein modifying the second input signal to create a modified second input signal having a desired frequency spectrum comprises creating a modified second input signal having at least one of a passband frequency response and a null passband frequency response.

3. The method of claim 1 wherein modifying the second input signal to create a modified second input signal having a desired frequency spectrum comprises adjusting at least one of a target center frequency and a target bandwidth of the desired frequency spectrum.

4. The method of claim 1 wherein creating the modified second signal having the desired frequency spectrum includes conditioning the second input signal prior to modifying the second input signal.

5. The method of claim 4 wherein conditioning the second input signal includes at least partially saturating the second input signal with respect to a target frequency.

6. The method of claim 4 wherein conditioning the second input signal includes at least partially saturating with respect to a target frequency a signal provided by a signal generation circuit and combining the at least partially saturated signal with the second input signal.

7. The method of claim 1 wherein modifying the third input signal to produce a fourth input signal comprises modifying at least on of amplitude, phase, and delay of the third input signal.

8. The method of claim 1 wherein adjusting at least one of phase, delay, amplitude magnitude, amplitude sign, and frequency spectrum of the modified second input signal with respect to the first input signal includes using a feed-forward method.

9. The method of claim 1 wherein adjusting at least one of phase, delay, amplitude magnitude, amplitude sign, and frequency spectrum of the modified second input signal with respect to the first input signal includes performing a deterministic algorithm.

10. The method of claim 9 wherein performing a deterministic algorithm includes determining an amplitude (α

) of the first input signal, introducing a first phase shift (φ

1) into at least one of the first input signal and the modified second input signal, determining a first amplitude (β

) of the output signal, determining a target phase shift (φ

) based on a relationship between α and

β

, and introducing the target phase shift φ

into the at least one of the first input signal and the modified second input signal.

11. The method of claim 10 wherein determining Φ

based on a relationship between α and

β

comprises calculating a first pair of prospective phase shifts using the equation Φ

P1=φ

1+π

+/−

2AR COS(β

/2α

), and selecting one phase shift from the first pair of prospective phase shifts Φ

P1 as the target phase shift Φ

.

12. The method of claim 11 wherein performing the deterministic algorithm includes introducing a second phase shift (φ

2) into the at least one of the first input signal and the modified second input signal, determining a second amplitude (δ

) of the output signal, calculating a second pair of prospective phase shifts using the equation Φ

P2=φ

2 +π

+/−

2AR COS(δ

/2α

), and selecting one phase shift from the first and second pairs of prospective phase shifts Φ

P1 and Φ

P2 as the target phase shift Φ

.

13. The method of claim 1 wherein the first input signal for which wideband frequency and bandwidth tunable filtering is required is a received signal Rx that contains both a desired signal S and transmit interference Tx′

, wherein the second input signal comprises data to be transmitted Tx, and wherein the output signal having the desired frequency response comprises a filtered output signal that contains S and in which the presence of transmit interference Tx′

is reduced.

14. The method of claim 13 wherein received signal Rx is received from a first antenna, data to be transmitted Tx is sent from a second antenna, and transmit interference Tx′

comprises interference from the second antenna.

15. The method of claim 13 wherein received signal Rx is received from a first antenna, data to be transmitted Tx is sent from the first antenna, and transmit interference Tx′

comprises signal reflections within the first antenna.

16. A non-transitory computer readable medium having stored thereon executable instructions that when executed by the processor of a computer control the computer to perform steps comprising:

receiving an input signal for which wideband frequency and bandwidth tunable filtering is desired;

creating a second input signal having at least one of a desired phase, amplitude, and delay relative to the first input signal;

modifying the second input signal to create a modified second input signal having a desired frequency spectrum, wherein creating the modified second input signal having the desired frequency spectrum includes creating a third input signal having at least one of a desired phase, amplitude, and delay relative to the second input signal, modifying the third input signal to produce a fourth input signal, and combining the second input signal and the fourth input signal to create the modified second input signal having the desired frequency spectrum;

adjusting at least one of phase, delay, amplitude magnitude, amplitude sign, and frequency spectrum of the modified second input signal with respect to the first input signal; and

combining the modified second input signal with the first input signal to create an output signal having the desired frequency response.