Reconfigurable downconverter for a multi-band positioning receiver

• US 20060176215A1
• Filed: 02/10/2005
• Published: 08/10/2006
• Est. Priority Date: 02/10/2005
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: King, Thomas M., Dubash, Noshir B.
• Granted Patent: US 7,551,127 B2
• Time in Patent Office: Days
• US Class Current: 342/357.640
• CPC Class Codes: G01S 19/32 Multimode operation in a single same satellite system, e.g. GPS L1/L2
• CPC Class Codes: G01S 19/33 Multimode operation in different systems which transmit time stamped messages, e.g. GPS/GLONASS
• CPC Class Codes: G01S 19/36 relating to the receiver frond end

Abstract

A reconfigurable downconverter (10) for a multi-band positioning receiver is operable with an RF synthesizer (18) with fixed output frequency, and a fixed wideband RF input (28). The downconverter (10) includes an RF mixer (12) operable to accept a range of frequencies that encompass the GPS and Galileo frequency bands and to output a downconverted IF signal (32). A fixed frequency local oscillator signal (34) is coupled to the RF mixer (12). At least one IF processor 14 further downconverts the downconverted IF signal (32) to at least one baseband signal (22). At least one of the IF processors (14) is reconfigurable for different frequency bands.

Claims

1. A reconfigurable downconverter for a multi-band receiver comprising:

a fixed RF mixer operable to accept a predetermined wide range of frequencies and output a downconverted IF signal;

a fixed frequency local oscillator coupled to the RF mixer; and

at least one IF processor coupled to the RF mixer, the IF processor operable to further downconvert the downconverted IF signal from the RF mixer to at least one baseband signal, the at least one IF processor being reconfigurable for different RF frequency bands.

2. The apparatus of claim 1, further comprising a programmable frequency divider that produces all the clock signals required for the at least one IF processor.

3. The apparatus of claim 1, further comprising a position processor coupled to the downconverter, the position processor providing control signals that are operable to select an operating frequency band of the downconverter.

4. The apparatus of claim 3, wherein the control signals are operable to reconfigure the functionality of the at least one IF processor and to program the programmable frequency divider.

5. The apparatus of claim 1, further comprising an RF synthesizer with fixed VCO frequency and a fixed wideband RF input coupled to the downconverter, wherein all frequency band selection and IF processor reconfiguration is done at IF frequencies.

6. The apparatus of claim 1, wherein a reconfigurable IF processor consists of an image-reject mixer with adjustable polyphase filter, a variable gain amplifier, at least one IF filter with variable bandwidth and frequency, an A/D converter with variable sample-rate capability, and a decimator with programmable decimation ratios.

7. The apparatus of claim 1, wherein a fixed IF processor consists of an image-reject mixer, a variable gain amplifier, at least one IF filter, an A/D converter, and a decimator.

8. The apparatus of claim 1, wherein the range of frequencies encompasses the operational frequencies of both the GPS and Galileo positioning systems.

9. The apparatus of claim 1, wherein the receiver is a positioning receiver using positioning signals transmitted by satellites.

10. A reconfigurable downconverter for a multi-band positioning receiver comprising:

an RF mixer operable to accept a predetermined wide range of frequencies and output a downconverted IF signal;

a fixed frequency local oscillator coupled to the RF mixer;

a plurality of IF processors coupled to the RF mixer, the IF processors operable to further downconvert the downconverted IF signal from the RF mixer to a plurality of baseband signal, the plurality of IF processors being reconfigurable for different frequency bands; and

a programmable frequency divider that produces all the clock signals required for the plurality of IF processors.

11. The apparatus of claim 10, further comprising a position processor coupled to the downconverter, the position processor providing control signals that are operable to select an operating frequency band of the downconverter and to reconfigure the functionality of the plurality of IF processors and to program the programmable frequency divider.

12. The apparatus of claim 10, further comprising a fixed RF synthesizer and a fixed wideband RF input coupled to the downconverter, wherein all frequency band selection and IF processor reconfiguration is done at IF frequencies.

13. The apparatus of claim 10, wherein the reconfigurable IF processors consists of an image-reject mixer with adjustable polyphase filter, a variable gain amplifier, at least one IF filter with variable bandwidth and frequency, an A/D converter with variable sample-rate capability, and a decimator with programmable decimation ratios.

14. The apparatus of claim 10, wherein the range of frequencies encompasses the range from about 1100 MHz to about 1600 MHz.

15. A multi-band positioning receiver comprising:

a fixed RF synthesizer;

a fixed wideband RF input;

a reconfigurable downconverter coupled to the synthesizer and RF input, the downconverter comprising;

an RF mixer operable to accept a predetermined wide range of frequencies and output a downconverted IF signal,

a fixed frequency local oscillator coupled to the RF mixer,

a plurality of IF processors coupled to the RF mixer, the IF processors operable to further downconvert the downconverted IF signal from the RF mixer to a plurality of baseband signal, the plurality of IF processors being reconfigurable for different frequency bands, and

a programmable frequency divider that produces all the clock signals required for the plurality of IF processors; and

a position processor coupled to the downconverter, the position processor providing control signals that are operable to select an operating frequency band of the downconverter and to reconfigure the functionality of the plurality of IF processors and to program the programmable frequency divider, wherein all frequency band selection and IF processor reconfiguration is done at IF frequencies.

16. The apparatus of claim 15, wherein the reconfigurable IF processors consists of an image-reject mixer with adjustable polyphase filter, a variable gain amplifier, at least one IF filter with variable bandwidth and frequency, an A/D converter with variable sample-rate capability, and a decimator with programmable decimation ratios.

17. The apparatus of claim 15, wherein the range of frequencies encompasses the range from about 1100 MHz to about 1600 MHz.

18. The apparatus of claim 15, wherein the local oscillator signal coupled to the RF mixer is approximately 1334 f₀, where f₀=1.023 MHz.