HIGH DYNAMIC RANGE RECEIVER FRONT-END WITH Q-ENHANCEMENT

• US 20100323654A1
• Filed: 06/23/2009
• Published: 12/23/2010
• Est. Priority Date: 06/23/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Judson, Bruce A., Nguyen, Cong T.
• Granted Patent: US 8,606,211 B2
• Time in Patent Office: Days
• US Class Current: 455/307
• CPC Class Codes: H03F 2200/241 A parallel resonance being added in shunt in the input circuit, e.g. base, gate, of an amplifier stage
• CPC Class Codes: H03F 3/195 in integrated circuits
• CPC Class Codes: H03H 11/52 simulating negative resistances
• CPC Class Codes: H03H 7/03 comprising means for compensation of loss
• CPC Class Codes: H03H 7/1775 Parallel LC in shunt or branch path H03H7/1791 takes precedence
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input

Abstract

A preselect circuit maintains the dynamic range of a received RF input signal during bandpass filtering of the received RF input signal. The preselect circuit includes a Q-deficient passive bandpass filter for coupling to an antenna to receive a received RF input signal. The preselect circuit further includes a Q-enhancement circuit coupled to the Q-deficient passive bandpass filter, wherein the Q-enhancement circuit increases a Q-value of the Q-deficient passive bandpass filter by compensating for resistive inductive losses in the bandpass filter.

Claims

1. A preselect circuit, comprising:

a Q-deficient passive bandpass filter for coupling to an antenna to receive a received RF input signal; and

a Q-enhancement circuit coupled to the Q-deficient passive bandpass filter, wherein the Q-enhancement circuit increases a Q-value of the Q-deficient passive bandpass filter by compensating for resistive inductive losses in the bandpass filter.

2. The circuit of claim 1, wherein the Q-deficient passive bandpass filter comprises a resonator configured as one of an LC tank circuit, transmission lines, cavity resonators and acoustic resonators.

3. The circuit of claim 1, wherein the Q-deficient passive bandpass filter comprises at least one discrete inductor and at least one discrete capacitor.

4. The circuit of claim 1, further comprising an impedance transformer coupling the received RF input signal to the Q-deficient passive bandpass filter.

5. The circuit of claim 1, wherein the Q-enhancement circuit includes an active device and the active device is the first active device through which the received RF input signal passes.

6. The circuit of claim 1, wherein the Q-enhancement circuit is formed as an integrated circuit and the Q-deficient passive bandpass filter is a discrete circuit.

7. The circuit of claim 1, wherein the Q-enhancement circuit is configured a Colpitts configuration.

8. The circuit of claim 1, further comprising an active buffer following the Q-enhancement circuit.

9. A receiver, comprising:

a preselector including;

a Q-deficient passive bandpass filter for coupling to an antenna to receive a received RF input signal; and

a Q-enhancement circuit coupled to the Q-deficient passive bandpass filter, wherein the Q-enhancement circuit increases a Q-value of the Q-deficient passive bandpass filter by compensating for resistive inductive losses in the bandpass filter; and

a mixer coupled to the preselector that down-converts a preselector filtered RF input signal.

10. The receiver of claim 9, further comprising an amplifier coupled between the preselector and the mixer that amplifies the preselector filtered RF input signal.

11. The receiver of claim 9, wherein the Q-deficient passive bandpass filter comprises a resonator configured as one of an LC tank circuit, transmission lines, cavity resonators and acoustic resonators.

12. The receiver of claim 9, wherein the Q-deficient passive bandpass filter comprises at least one discrete inductor and at least one discrete capacitor.

13. The receiver of claim 9, further comprising an impedance transformer coupling the received RF input signal to the Q-deficient passive bandpass filter.

14. The receiver of claim 9, wherein the Q-enhancement circuit includes an active device and the active device is the first active device through which the received RF input signal passes.

15. The receiver of claim 9, wherein the Q-enhancement circuit is formed as an integrated circuit and the Q-deficient passive bandpass filter is a discrete circuit.

16. The receiver of claim 9, wherein the Q-enhancement circuit is configured a Colpitts configuration.

17. The receiver of claim 9, further comprising an active buffer following the Q-enhancement circuit.

18. A wireless communication device, comprising:

an antenna; and

a receiver coupled to the antenna, the receiver including;

a Q-deficient passive bandpass filter for coupling to the antenna to receive a received RF input signal; and

a Q-enhancement circuit coupled to the Q-deficient passive bandpass filter, wherein the Q-enhancement circuit increases a Q-value of the Q-deficient passive bandpass filter by compensating for resistive inductive losses in the bandpass filter.

19. A method, comprising:

receiving an RF input signal from an antenna;

passively bandpass filtering the RF input signal in a Q-deficient passive bandpass filter prior to the RF input signal being subjected to any active circuit elements; and

enhancing a deficient Q-value of the Q-deficient passive bandpass filter.

20. The method of claim 19, wherein the passively bandpass filtering the RF input signal further comprises maintaining a dynamic range of the RF input signal during the passively bandpass filtering.

21. The method of claim 19, further comprising impedance transforming the RF input signal prior to passively filtering the RF input signal.

22. A circuit, comprising:

means for receiving an RF input signal from an antenna;

means for passively bandpass filtering the RF input signal in a Q-deficient passive bandpass filter prior to the RF input signal being subjected to any active circuit elements; and

means for enhancing a deficient Q-value of the Q-deficient passive bandpass filter.

23. The method of claim 22, further comprising means for impedance transforming the RF input signal prior to passively filtering the RF input signal.