RECEIVER CAPABLE OF CONCURRENTLY COLLECTING DUAL BAND SIGNALS, AND METHOD THEREOF

• US 20120252395A1
• Filed: 03/28/2011
• Published: 10/04/2012
• Est. Priority Date: 03/28/2011
• Status: Active Grant

• Current Assignee: National Taiwan University (Government of The Republic of China), MediaTek, Inc.
• Original Assignee: National Taiwan University (Government of The Republic of China), MediaTek, Inc.
• Inventors: Chen, Yi-Jan, Cheng, Chi-Wei, Yu, Yueh-Hua
• Granted Patent: US 8,693,967 B2
• Time in Patent Office: Days
• US Class Current: 455/319
• CPC Class Codes: H04B 1/0007 wherein the AD/DA conversion occurs at radiofrequency or intermediate frequency stage
• CPC Class Codes: H04B 1/0053 with common antenna for more than one band

Abstract

A receiver of a GNSS system is provided. The receiver comprises two mixers and a processing circuit. The first mixer down-converts an input radio-frequency signal comprising a first GNSS signal and a second GNSS signal into a first low-frequency signal. The second mixer down-converts the input radio-frequency signal into a second low-frequency signal. The processing circuit generates at least one phase-shifted low-frequency signal according to at least the first low-frequency signal, extract signal components of the first GNSS signal by rejecting signal components of the second GNSS signal according to the second low-frequency signal and the at least one phase-shifted low-frequency signal, and extract signal components of the second GNSS signal by rejecting signal components of the first GNSS signal according to the second low-frequency signal and the at least one phase-shifted low-frequency signal. The first and second GNSS signals are situated in different frequency ranges.

Claims

1. A receiver for receiving a first communication signal and a second communication signal, comprising:

a first mixer, for down-converting an input radio-frequency signal comprising the first communication signal and the second communication signal into a first low-frequency signal according to a first local oscillating signal;

a second mixer, for down-converting the input radio-frequency signal into a second low-frequency signal according to a second local oscillating signal; and

a processing circuit, coupled to the first mixer and the second mixer, for generating at least one phase-shifted low-frequency signal according to at least the first low-frequency signal, for extracting signal components of the first communication signal by rejecting signal components of the second communication signal according to the second low-frequency signal and the at least one phase-shifted low-frequency signal, and for extracting signal components of the second communication signal by rejecting signal components of the first communication signal according to the second low-frequency signal and the at least one phase-shifted low-frequency signal;

wherein the first communication signal is situated in a first frequency range different from a second frequency range in which the second communication signal is situated.

2. The receiver of claim 1, wherein the processing circuit comprises:

a phase shifter, coupled to the first mixer, for shifting a phase of the first low-frequency signal to generate the phase-shifted low-frequency signal;

a first processing unit, coupled to the phase shifter and the second mixer, for generating an addition result of the phase-shifted low-frequency signal and the second low-frequency signal to reject the signal components of the second communication signal so as to extract the signal components of the first communication signal;

a second processing unit, coupled to the phase shifter and the second mixer, for generating a subtraction result of the phase-shifted low-frequency signal and the second low-frequency signal to reject the signal components of the first communication signal so as to extract the signal components of the second communication signal.

3. The receiver of claim 2, wherein the phase shifter is arranged to shift the phase of the first low-frequency signal by 90 degrees.

4. The receiver of claim 1, further comprising:

a synthesizer, coupled to the first mixer and the second mixer, for generating both the first and second oscillating signals, wherein the first and second oscillating signals are orthogonal to each other, and frequency of the first and second oscillating signals is between frequency ranges of the first and second GNSS signals.

5. The receiver of claim 1, wherein the processing circuit comprises:

a first polyphase filter, coupled to the first and second mixer, for rejecting the second communication signal and extracting the first communication signal according to the first and second low-frequency signals; and

a second polyphase filter, coupled to the first and second mixer, for rejecting the first communication signal and extracting the second communication signal according to the first and second low-frequency signals.

6. The receiver of claim 5, wherein the processing circuit further comprises a processing unit, coupled to the first and second polyphase filters, for generating an addition result in accordance with the outputs of the first polyphase filter, and for generating an addition result in accordance with the outputs of the second polyphase filter.

7. The receiver of claim 1, further comprising:

a third mixer, coupled between the first mixer and the processing circuit, for down-converting the first low-frequency signal into a first converted low-frequency signal according to a third local oscillating signal; and

a fourth mixer, coupled between the second mixer and the processing circuit, for down-converting the second low-frequency signal into a second converted low-frequency signal according to a fourth local oscillating signal;

wherein the processing circuit is arranged to generate the at least one phase-shifted low-frequency signal according to the first converted low-frequency signal.

8. The receiver of claim 7, wherein the processing circuit comprises:

a phase shifter, coupled to the third mixer, for shifting a phase of the first converted low-frequency signal to generate the phase-shifted low-frequency signal;

a first processing unit, coupled to the phase shifter and the fourth mixer, for generating an addition result of the phase-shifted low-frequency signal and the second converted low-frequency signal to reject the second communication signal so as to extract the first communication signal;

a second processing unit, coupled to the third mixer and the fourth mixer, for generating an addition result of the first converted low-frequency signal and the second converted low-frequency signal to reject the first communication signal so as to extract the second communication signal.

9. The receiver of claim 8, wherein the phase shifter is arranged to shift the phase of the first converted low-frequency signal by 180 degrees.

10. The receiver of claim 7, further comprising:

a first synthesizer, coupled to the first mixer and the second mixer, for generating both the first and second oscillating signals; and

a second synthesizer, coupled to the third mixer and the fourth mixer, for generating both the third and fourth oscillating signals;

wherein an oscillation frequency of the first synthesizer is different from an oscillation frequency of the second synthesizer.

11. A method for receiving a first communication signal and a second communication signal, comprising:

down-converting an input radio-frequency signal comprising the first communication signal and the second communication signal into a first low-frequency signal according to a first local oscillating signal;

down-converting the input radio-frequency signal into a second low-frequency signal according to a second local oscillating signal;

generating at least one phase-shifted low-frequency signal according to at least the first low-frequency signal;

extracting signal components of the first communication signal by rejecting signal components of the second communication signal according to the second low-frequency signal and the at least one phase-shifted low-frequency signal; and

extracting signal components of the second communication signal by rejecting signal components of the first communication signal according to the second low-frequency signal and the at least one phase-shifted low-frequency signal;

wherein the first communication signal is situated in a first frequency range different from a second frequency range in which the second communication signal is situated.

12. The method of claim 11, wherein the step of generating the at least one phase-shifted low-frequency signal comprises:

shifting a phase of the first low-frequency signal to generate the phase-shifted low-frequency signal;

the step of extracting the signal components of the first communication signal comprises;

generating an addition result of the phase-shifted low-frequency signal and the second low-frequency signal to reject the signal components of the second communication signal so as to extract the signal components of the first communication signal; and

the step of extracting the signal components of the second communication signal comprises;

generating a subtraction result of the phase-shifted low-frequency signal and the second low-frequency signal to reject the signal components of the first communication signal so as to extract the signal components of the second communication signal.

13. The method of claim 12, wherein the phase of the first low-frequency signal is shifted by 90 degrees.

14. The method of claim 11, wherein the first and second oscillating signals are orthogonal to each other, and a frequency of the first and second oscillating signals is between frequency ranges of the first and second GNSS signals.

15. The method of claim 11, further comprising:

down-converting the first low-frequency signal into a first converted low-frequency signal according to a third local oscillating signal; and

down-converting the second low-frequency signal into a second converted low-frequency signal according to a fourth local oscillating signal;

wherein the step of generating the at least one phase-shifted low-frequency signal comprises;

referring to a phase of the first converted low-frequency signal corresponding to the first low-frequency signal to generate the at least one phase-shifted low-frequency signal.

16. The method of claim 15, wherein the step of generating the at least one phase-shifted low-frequency signal comprises:

shifting a phase of the first converted low-frequency signal to generate the phase-shifted low-frequency signal;

the step of extracting the first communication signal comprises;

generating an addition of the phase-shifted low-frequency signal and the second converted low-frequency signal to reject the second communication signal and extract the first communication signal; and

the step of extracting the second communication signal comprises;

generating an addition result of the first converted low-frequency signal and the second converted low-frequency signal to reject the first communication signal and extract the second communication signal.

17. The method of claim 15, wherein the phase of the first converted low-frequency signal is shifted by 180 degrees.

18. The method of claim 15, further comprising:

providing a first synthesizer to generate both the first and second oscillating signals; and

utilizing a second synthesizer to generate both the third and fourth oscillating signals;

wherein an oscillation frequency of the first synthesizer is different from an oscillation frequency of the second synthesizer.

19. A receiver for receiving a first communication signal and a second communication signal, comprising:

a first mixer, for down-converting an input radio-frequency signal comprising the first communication signal and the second communication signal into a first low-frequency signal according to a first local oscillating signal;

a second mixer, for down-converting the input radio-frequency signal into a second low-frequency signal according to a second local oscillating signal; and

a first polyphase filter, coupled to the first mixer and the second mixer, for extracting signal components of the first communication signal by rejecting signal components of the second communication signal according to the first and second low-frequency signals;

wherein the first communication signal is situated in a first frequency range different from a second frequency range in which the second communication signal is situated.

20. The receiver of claim 19, further comprising a second polyphase filter, coupled to the first mixer and the second mixer, for extracting signal components of the second communication signal by rejecting signal components of the first communication signal according to the first and second low-frequency signals.

21. A receiver for receiving a first GNSS signal and a second GNSS signal, comprising:

a first mixer, for down-converting an input radio-frequency signal comprising the first GNSS signal and the second GNSS signal into a first low-frequency signal according to a first local oscillating signal;

a second mixer, for down-converting the input radio-frequency signal into a second low-frequency signal according to a second local oscillating signal; and

a processing circuit, coupled to the first mixer and the second mixer, for generating at least one phase-shifted low-frequency signal according to at least the first low-frequency signal, for extracting signal components of the first GNSS signal by rejecting signal components of the second GNSS signal according to the second low-frequency signal and the at least one phase-shifted low-frequency signal, and for extracting signal components of the second GNSS signal by rejecting signal components of the first GNSS signal according to the second low-frequency signal and the at least one phase-shifted low-frequency signal;

wherein the first GNSS signal is situated in a first frequency range different from a second frequency range in which the second GNSS signal is situated.