IF PROCESS ENGINE AND RECEIVER HAVING THE SAME AND METHOD FOR REMOVING IF CARRIERS USED THEREIN

• US 20090081978A1
• Filed: 12/02/2008
• Published: 03/26/2009
• Est. Priority Date: 09/01/2006
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Tsu, Ping-hsuan, Chen, Chun-nan
• Granted Patent: US 9,124,345 B2
• Time in Patent Office: Days
• US Class Current: 455/255
• CPC Class Codes: H04B 1/0007 wherein the AD/DA conversion occurs at radiofrequency or intermediate frequency stage
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/0067 with one or more circuit blocks in common for different bands
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22

Abstract

A GNSS receiver having an IF process engine is disclosed. The IF process engine provides a plurality of carriers with different frequencies and down converts IF signals into baseband signals by using the carriers in a time division multiplex (TDM) schedule. The IF process engine has a local oscillator part for generating the carriers with different frequencies; an IF down-converter for respectively mixing the IF signal with the carriers generated by the local oscillator part to generate IF removed signal segments; a time division multiplex (TDM) controller for scheduling the respective mixing operations of the IF down-converter for the IF signal with the respective carriers; and a buffer for storing the IF removed signal segments generated by the IF down-converter.

Claims

1. An intermediate frequency (IF) process engine for a GNSS receiver, comprising:

a local oscillator part for generating a plurality of carriers with different frequencies;

an IF down-converter for respectively mixing IF signals with the carriers generated by the local oscillator part to generate IF removed signal segments;

a time division multiplex (TDM) controller for scheduling the respective mixing operations of the IF down-converter; and

a buffer for storing the IF removed signal segments generated by the IF down-converter.

2. The IF process engine of claim 1, further comprising a multiplexer for passing one of the carriers a time under the control of the TDM controller.

3. The IF process engine of claim 2, wherein the local oscillator part comprises a plurality of local oscillators, each local oscillator generates one of the carriers.

4. The IF process engine of claim 3, wherein each of the local oscillators is implemented by a numerical controlled oscillator (NCO).

5. The IF process engine of claim 1, wherein the local oscillator part comprises a single local oscillator.

6. The IF process engine of claim 5, wherein the local oscillator is implemented by an NCO, the NCO generates the carriers with different frequencies by accumulating NCO phases with different steps.

7. The IF process engine of claim 6, further comprising a phase latch for latching the accumulated NCO phases.

8. The IF process engine of claim 1, further comprising a digital filter part for filter out noises of the IF removed signal segments generated by the IF down-converter.

9. The IF process engine of claim 8, wherein the digital filter part is implemented by a digital filter bank having a plurality of digital filters, each of which is used for only allowing the IF removed signal segments down converted by mixing one carrier with the IF signal to pass to the buffer to be stored.

10. The IF process engine of claim 9, wherein the digital filter part comprises a single digital filter, and the IF process engine further comprises a state latch for latching states of the digital filter so that the digital filter allows the IF removed signal segments down converted by mixing the respective carrier with the IF signal to pass to the buffer to be stored.

11. A GNSS receiver comprising:

an RF front end for down converting the RF signals into intermediate frequency (IF) signals;

an IF process engine for providing a plurality of carriers with different frequencies and down converting the IF signals into baseband signals by using the carriers in a time division multiplex (TDM) schedule; and

a correlator engine for correlating the baseband signals with codes to generate correlation results.

12. The GNSS receiver of claim 11, wherein the IF process engine comprises:

a local oscillator part for generating a plurality of carriers with different frequencies;

an IF down-converter for respectively mixing the IF signals with the carriers generated by the local oscillator part to generate IF removed signal segments;

a time division multiplex (TDM) controller for scheduling the respective mixing operations of the IF down-converter; and

a buffer for storing the IF removed signal segments generated by the IF down-converter.

13. The GNSS receiver of claim 12, wherein the IF process engine further comprises a multiplexer for passing one of the carriers a time under the control of the TDM controller.

14. The GNSS receiver of claim 13, wherein the local oscillator part comprises a plurality of local oscillators, each local oscillator generates one of the carriers.

15. The GNSS receiver of claim 14, wherein each of the local oscillators is implemented by a numerical controlled oscillator (NCO).

16. The GNSS receiver of claim 12, wherein the local oscillator part comprises a single local oscillator.

17. The GNSS receiver of claim 16, wherein the local oscillator is implemented by an NCO, the NCO generates the carriers with different frequencies by accumulating NCO phases with different steps.

18. The GNSS receiver of claim 17, further comprising a phase latch for latching the accumulated NCO phases.

19. The GNSS receiver of claim 12, wherein the GNSS receiver further comprises a digital filter part for filter out noises of the IF removed signal segments generated by the IF down-converter.

20. The GNSS receiver of claim 19, wherein the digital filter part is implemented by a digital filter bank having a plurality of digital filter, each of which is used for only allowing the IF removed signal segments down converted by mixing one carrier with the IF signal to pass to the buffer to be stored.

21. The GNSS receiver of claim 20, wherein the digital filter part comprises a single digital filter, and the IF process engine further comprises a state latch for latching states of the digital filter so that the digital filter allows the IF removed signal segments down converted by mixing the respective carrier with the IF signal to pass to the buffer to be stored.

22. The GNSS receiver of claim 11, wherein the IF process engine operates with a speed which is the plurality of times of that of the RF front end.

23. A method for removing intermediate frequency (IF) carriers with different frequencies from IF signals in a GNSS receiver, the method comprising steps of:

generating a plurality of carriers with different frequencies;

mixing the respective carriers with IF signals to generate IF removed signal segments base on a TDM schedule; and

storing the IF removed signal segments.