Compensation Apparatus for Receiver Asymmetric Wide Passband Frequency Response with 25% Duty Cycle Passive Mixer

• US 20130115894A1
• Filed: 11/02/2012
• Published: 05/09/2013
• Est. Priority Date: 11/03/2011
• Status: Active Grant

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Wang, Feng, Irvine, Robert Grant, Yin, Ping, Yim, Seong-Mo, Liao, Chengfang, Chi, Yusong
• Granted Patent: US 8,886,144 B2
• Time in Patent Office: Days
• US Class Current: 455/73
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver

Abstract

A receiver compensation method comprising receiving a radio frequency signal, amplifying the radio frequency signal, thereby producing an amplified signal, compensating the amplified signal, thereby producing a compensated signal, and mixing the compensated signal, thereby producing a mixed compensated signal, wherein the mixed compensated signal has a first gain difference between a positive differential from a center frequency and a negative differential from the center frequency and wherein the first gain differential is smaller than a second gain differential that would be obtained by mixing the amplified signal without compensating the amplified signal.

Claims

1. An apparatus, comprising:

a low noise amplifier having an output;

a mixer having an input; and

a compensator coupled to the output of the low noise amplifier and to the input of the mixer,

wherein the compensator comprises a balun and one or more capacitors, and

wherein the capacitors are coupled to the balun on an input side, an output side, or both the input side and the output side of the balun.

2. The apparatus of claim 1, wherein the compensator is configured to reduce an asymmetric frequency response with respect to a positive offset and a negative offset from a carrier frequency of the receiver as compared with an identical apparatus that lacks the compensator.

3. The apparatus of claim 2, wherein the compensator has a tunable frequency response via the capacitors.

4. The apparatus of claim 3, wherein the tunable frequency response is adjustable depending on the band of operation.

5. The apparatus of claim 4, further comprising a local oscillator with a duty cycle of about 25%, wherein the mixer is coupled to one or more outputs of the local oscillator.

6. The apparatus of claim 5, wherein the apparatus further comprises an antenna, an antenna switch coupled to the antenna, a duplexer coupled to the antenna switch and the low noise amplifier, a filter coupled to the mixer, an amplifier coupled to the filter, an analog to digital converter coupled to the filter, and a digital signal processor coupled to the analog to digital converter.

7. A mobile device comprising;

an antenna;

an antenna switch coupled to the antenna;

a duplexer coupled to the antenna switch;

a low noise amplifier coupled to the duplexer;

a compensator comprising a balun coupled to the low noise amplifier;

a mixer coupled to the compensator;

a filter coupled to the mixer;

an amplifier coupled to the filter;

an analog to digital converter coupled to the amplifier;

a logic unit coupled to the analog to digital converter; and

a screen coupled to the logic unit.

8. The mobile device of claim 7, wherein the mobile device further comprises one or more capacitors, wherein the capacitors are positioned between the low noise amplifier and the mixer.

9. The mobile device of claim 8, wherein the capacitors are coupled to the balun on an input side but not on an output side of the balun.

10. The mobile device of claim 8, wherein the capacitors are couple to an output side but not to an input side of the balun.

11. The mobile device of claim 8, wherein the capacitors are coupled to both the input side and the output side of the balun.

12. The mobile device of claim 8, further comprising a microphone and speaker each coupled to the logic unit.

13. The mobile device of claim 8, further comprising a switch or a transistor coupled to the capacitors.

14. The mobile device of claim 8, further comprising a local oscillator with a duty cycle of 25% coupled to the mixer.

15. A method comprising:

receiving a radio frequency signal;

amplifying the radio frequency signal, thereby producing an amplified signal;

compensating the amplified signal, thereby producing a compensated signal; and

mixing the compensated signal, thereby producing a mixed compensated signal,

wherein the mixed compensated signal has a first gain difference between a positive differential from a center frequency and a negative differential from the center frequency, and

wherein the first gain differential gain is smaller than a second gain differential that would be obtained by mixing the amplified signal without compensating the amplified signal.

16. The method of claim 15, wherein the amplified signal is compensated by passing the amplified signal through a balun and a capacitor coupled to the balun.

17. The method of claim 16, wherein the amplified signal passes through the capacitor coupled to an input side of the balun and then through the balun.

18. The method of claim 16, wherein the amplified signal passes through the balun and then through the capacitor coupled to an output side of the balun.

19. The method of claim 16, wherein the amplified signal passes through a first capacitor coupled to an input side of the balun, then through the balun, and then through a second capacitor coupled to an output side of the balun.

20. The method of claim 16, wherein the first differential gain is about zero.