Common signal generation for an RF receiver

• US 7,606,328 B1
• Filed: 06/18/2004
• Issued: 10/20/2009
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Milton, Kevin L.
• Primary Examiner(s): Bayard; Emmanuel
• Application Number:
  US10/871,393
• Time in Patent Office: 1,950 Days
• Field of Search: 375/137, 375/142, 375/147, 375/316, 375/326, 375/329, 375/331
• US Class Current: 375/316
• CPC Class Codes: G01S 19/32 Multimode operation in a single same satellite system, e.g. GPS L1/L2
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: H04B 1/0032 with analogue quadrature frequency conversion to and from the baseband quadrature modulators and demodulators per se H03D3/007, H03C3/40
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes

Abstract

A common signal generating sub-system (CSGS) for a radio frequency (RF) receiver. The CSGS includes a down converter section and a digitizer section. The down converter section receives intermediate frequency (IF) signals and injection frequency signals from an RF/IF processing section of an RF receiver and translates the IF signals to analog intermediate frequency (IF) signals preserving the spectra thereof. The analog IF signals comprise analog in-phase IF signals and analog quadrature IF signals. The digitizer section utilizes a locally generated sampling rate signal (LGSRS) and converts the analog in-phase IF signals and the analog quadrature IF signals to a common digital in-phase IF signal and a common digital quadrature IF signal. The common digital IF signals can be subsequently processed by a digital processing section of the RF receiver. Implemented in a GPS system, by selecting the proper injection signals and A/D sampler rate, the L1, L2 and L5 signals can be converted to a single digital IF frequency for use with a common digital processing section.

Claims

1. A common signal generating sub-system (CSGS) for a radio frequency (RF) receiver, said CSGS comprising:

a down converter section for receiving intermediate frequency (IF) signals and injection frequency signals from an RF/IF processing section of an RF receiver and for translating said IF signals to analog intermediate frequency (IF) signals preserving the spectra thereof, said analog IF signals comprising analog in-phase IF signals and analog quadrature IF signals; and

,

a digitizer section for utilizing a locally generated sampling rate signal (LGSRS) and converting said analog in-phase IF signals and said analog quadrature IF signals to a common digital in-phase IF signal and a common digital quadrature IF signal, wherein said common digital IF signals can be subsequently processed by a digital processing section of the RF receiver, said LGSRS providing additional frequency translation by aliasing said analog in-phase IF signals and analog quadrature IF signals using an A/D sampler rate, wherein

said digitizer section, comprises;

a first analog to digital converter for receiving said analog in-phase IF signals and said LGSRS and providing said digital in-phase IF signal; and

,

a second analog to digital converter for receiving said analog quadrature IF signals and said LGSRS and providing said digital quadrature IF signal,

wherein the combination of the down converter section and the digitizer section perform frequency translation in conjunction with each other.

2. The common signal generating sub-system (CSGS) of claim 1 wherein said RF receiver comprises a satellite receiver and said IF signals comprise satellite IF signals.

3. The common signal generating sub-system (CSGS) of claim 1 wherein said RF receiver comprises a GPS receiver and said IF signals comprise GPS IF signals.

4. The common signal generating sub-system (CSGS) of claim 3 wherein said downconverter section comprises:

a first mixer for receiving said GPS IF signals and an in-phase (I) injection frequency signal of said injection frequency signals and providing said analog in-phase IF signals; and

,

a second mixer for receiving said GPS IF signals and a quadrature (Q) injection frequency signal of said injection frequencies and providing said analog quadrature IF signals.

5. The common signal generating sub-system (CSGS) of claim 3 wherein said injection frequency signals are 137 Fo/8, where Fo=10.23 MHz;

and, said LGSRS is 5Fo.

6. The common signal generating sub-system (CSGS) of claim 3 wherein said injection frequency signals are 137 Fo/8, where Fo=10.23 MHz;

and, said LGSRS is 39Fo.

7. A radio frequency (RF) receiver, comprising:

an RF/IF processing section for receiving source signals from an RF source, for performing desired filtering and for providing intermediate frequency (IF) signals and injection frequency signals;

a common signal generating sub-system (CSGS) operatively associated with said RF/IF processing section, comprising;

a down converter section for receiving said intermediate frequency (IF) signals and said injection frequency signals and for translating said IF signals to analog intermediate frequency (IF) signals preserving the spectra thereof, said analog IF signals comprising analog in-phase IF signals and analog quadrature IF signals; and

a digitizer section for utilizing a locally generated sampling rate signal (LGSRS) and converting said analog in-phase IF signals and said analog quadrature IF signals to a common digital in-phase IF signal and a common digital quadrature IF signal; and

,

a digital processing section for receiving the common digital in-phase IF signal and common digital quadrature IF signal and performing the remaining digital processing for acquisition and tracking of the source signals, said LGSRS providing additional frequency translation by aliasing said analog in-phase IF signals and analog quadrature IF signals using an A/D sampler rate, wherein

said digitizer section, comprises;

a first analog to digital converter for receiving said analog in-phase IF signals and said LGSRS and providing said digital in-phase IF signal; and

,

a second analog to digital converter for receiving said analog quadrature IF signals and said LGSRS and providing said digital quadrature IF signal,

wherein the combination of the down converter section and the digitizer section perform frequency translation in conjunction with each other.

8. The RF receiver of claim 7 wherein said receiver comprises a satellite receiver and said IF signals comprise satellite IF signals.

9. The RF receiver of claim 7 wherein said receiver comprises a GPS receiver and said IF signals comprise GPS IF signals.

10. The RF receiver of claim 9, wherein said downconverter section comprises:

a first mixer for receiving said GPS IF signals and an in-phase (I) injection frequency signal of said injection frequency signals and providing said analog in-phase IF signals; and

,

a second mixer for receiving said GPS IF signals and a quadrature (Q) injection frequency signal of said injection frequencies and providing said analog quadrature IF signals.

11. The RF receiver of claim 9, wherein said injection frequency signals are 137 Fo/8, where Fo=10.23 MHz;

and, said LGSRS is 5Fo.

12. The RF receiver of claim 9, wherein said injection frequency signals are 137 Fo/8, where Fo=10.23 MHz;

and, said LGSRS is 39Fo.

13. A method for processing radio frequency (RF) signals from an RF source, comprising the steps of:

receiving source signals from an RF source, performing desired filtering and providing intermediate frequency (IF) signals and injection frequency signals;

translating said IF signals to analog intermediate frequency (IF) signals preserving the spectra thereof, said analog IF signals comprising analog in-phase IF signals and analog quadrature IF signals;

utilizing a locally generated sampling rate signal (LGSRS) and converting said analog in-phase IF signals and said analog quadrature IF signals to a common digital in-phase IF signal and a common digital quadrature IF signal; and

,

utilizing said common digital in-phase IF signal and common digital quadrature IF signal for performing the remaining digital processing for acquisition and tracking of the source signals, said LGSRS providing additional frequency translation by aliasing said analog in-phase IF signals and analog quadrature IF signals using an A/D sampler rate, wherein,

said step of utilizing a locally generated sampling rate signal (LGSRS) and converting said analog in-phase IF signals and said analog quadrature IF signals, comprises the steps of;

utilizing a first analog to digital converter for receiving said analog in-phase IF signals and said LGSRS and providing said digital in-phase IF signal; and

,

utilizing a second analog to digital converter for receiving said analog quadrature IF signals and said LGSRS and providing said digital quadrature IF signal,

wherein the combination of the down converter section and the digitizer section perform frequency translation in conjunction with each other.

14. The method of claim 13 wherein said step of receiving source signals comprises receiving source signals from a satellite receiver and said step of providing IF signals comprises providing satellite IF signals.

15. The method of claim 13 wherein said step of receiving source signals comprises receiving source signals from a GPS receiver and said step of providing IF signals comprises providing GPS IF signals.

16. The method of claim 15 wherein said step of translating said IF signals to analog intermediate frequency (IF) signals comprises the steps of:

mixing said GPS IF signals and an in-phase (I) injection frequency signal of said injection frequency signals and providing said analog in-phase IF signals; and

,

mixing said GPS IF signals and a quadrature (Q) injection frequency signal of said injection frequencies and providing said analog quadrature IF signals.

17. The method of claim 15, wherein said injection frequency signals are 137 Fo/8, where Fo=10.23 MHz;

and, said LGSRS is 5Fo.