Radio frequency (RF) signal generator and method for providing test signals for testing multiple RF signal receivers

• US 8,036,617 B2
• Filed: 12/15/2008
• Issued: 10/11/2011
• Est. Priority Date: 12/15/2008
• Status: Expired due to Fees

• Current Assignee: LitePoint Corporation (Teradyne Incorporated)
• Original Assignee: LitePoint Corporation (Teradyne Incorporated)
• Inventors: Olgaard, Christian Volf
• Primary Examiner(s): YOUNG, BRIAN K
• Application Number:
  US12/335,241
• Publication Number:
  US 20100148827A1
• Time in Patent Office: 1,030 Days
• Field of Search: 455/226.1, 455/423, 455/45, 455/62, 455/63.1, 455/67.11, 455/67.13, 375/296, 375/297
• US Class Current: 455/226.1
• CPC Class Codes: G01S 19/23 Testing, monitoring, correcting or calibrating of receiver elements

Abstract

A test signal interface and method for allowing sharing of multiple test signal generators among multiple devices under test (DUTs). Digital baseband test signals generated by the multiple test signal generators are combined and converted to a baseband analog signal for conversion to a radio frequency (RF) signal for testing the multiple DUTs.

Claims

1. An apparatus including a radio frequency (RF) signal generator for providing a test signal to be used in testing a plurality of RF signal receivers, comprising:

signal generator circuitry responsive to a first plurality of digital baseband signals and a plurality of digital gain control signals by providing an analog baseband signal corresponding to a combination of said first plurality of digital baseband signals; and

frequency conversion circuitry coupled to said signal generator circuitry and responsive to said analog baseband signal by providing a RF signal corresponding to said combination of said first plurality of digital baseband signals.

2. The apparatus of claim 1, wherein said signal generator circuitry comprises:

digital signal generator circuitry responsive to said first plurality of digital baseband signals by providing a related second plurality of digital baseband signals;

digital gain control circuitry coupled to said digital signal generator circuitry and responsive to said plurality of digital gain control signals and said second plurality of digital baseband signals by providing a related third plurality of digital baseband signals, wherein ratios of respective related ones of said second and third pluralities of digital baseband signals correspond to respective ones of said plurality of digital gain control signals; and

signal conversion circuitry coupled to said digital gain control circuitry and responsive to said third plurality of digital baseband signals by providing said analog baseband signal.

3. The apparatus of claim 2, wherein said digital gain control circuitry comprises digital signal multiplication circuitry responsive to said plurality of digital gain control signals and said second plurality of digital baseband signals by providing a plurality of digital product signals as said related third plurality of digital baseband signals.

4. The apparatus of claim 2, wherein said signal conversion circuitry comprises:

signal summing circuitry responsive to said third plurality of digital baseband signals by providing a digital sum signal; and

digital-to-analog conversion (DAC) circuitry coupled to said signal summing circuitry and responsive to said digital sum signal by providing said analog baseband signal.

5. The apparatus of claim 1, further comprising analog amplifier circuitry coupled to said frequency conversion circuitry and responsive to said RF signal and a gain control signal by providing a corresponding amplified RF signal having a magnitude related to said gain control signal.

6. The apparatus of claim 1, further comprising signal dividing circuitry coupled to said frequency conversion circuitry and responsive to said RF signal by providing a plurality of corresponding RF signals.

7. The apparatus of claim 1, further comprising:

analog amplifier circuitry coupled to said frequency conversion circuitry and responsive to a gain control signal and said RF signal by providing a corresponding amplified RF signal having a magnitude related to said gain control signal; and

signal dividing circuitry coupled to said analog amplifier circuitry and responsive to said amplified RF signal by providing a plurality of corresponding RF signals.

8. An apparatus including an analog data signal generator for providing a test data signal to be used in testing a plurality of data signal receivers, comprising:

a plurality of digital signal generator circuits responsive to a plurality of digital code signals by providing a first plurality of digital baseband signals;

a plurality of digital gain control circuits coupled to said plurality of digital signal generator circuits and responsive to said first plurality of digital baseband signals and a plurality of digital gain control signals by providing a second plurality of digital baseband signals, wherein ratios of respective related ones of said first and second pluralities of digital baseband signals correspond to respective ones of said plurality of digital gain control signals;

digital signal combining circuitry coupled to said plurality of digital gain control circuits and responsive to said second plurality of digital baseband signals by providing a digital combination signal related to said second plurality of digital baseband signals; and

digital-to-analog conversion (DAC) circuitry coupled to said digital signal combining circuitry and responsive to said digital combination signal by providing an analog baseband signal related to a combination of said digital code signals.

9. The apparatus of claim 8, further comprising frequency conversion circuitry coupled to said DAC circuitry and responsive to said analog baseband signal by providing a RF signal related to said combination of said digital code signals.

10. The apparatus of claim 9, further comprising analog amplifier circuitry coupled to said frequency conversion circuitry and responsive to said RF signal and a gain control signal by providing a corresponding amplified RF signal having a magnitude related to said gain control signal.

11. The apparatus of claim 9, further comprising signal dividing circuitry coupled to said frequency conversion circuitry and responsive to said RF signal by providing a plurality of corresponding RF signals.

12. The apparatus of claim 9, further comprising:

analog amplifier circuitry coupled to said frequency conversion circuitry and responsive to said RF signal and a gain control signal by providing a corresponding amplified RF signal having a magnitude related to said gain control signal; and

signal dividing circuitry coupled to said analog amplifier circuitry and responsive to said amplified RF signal by providing a plurality of corresponding RF signals.

13. A method for providing a test data signal for testing a plurality of data signal receivers, comprising:

receiving a first plurality of digital codes and in response thereto providing a first plurality of digital baseband signals each of which is related to a respective one of said first plurality of digital codes;

receiving said first plurality of digital baseband signals and a plurality of digital gain control signals and in response thereto providing a second plurality of digital baseband signals, wherein ratios of respective related ones of said first and second pluralities of digital baseband signals correspond to respective ones of said plurality of digital gain control signals;

combining said second plurality of digital baseband signals to provide a digital combination signal related to said second plurality of digital baseband signals; and

converting said digital combination signal to one or more RF signals, wherein each of said one or more RF signals includes a plurality of RF signal components related to said first plurality of digital codes;

converting, with each one of a plurality of data signal receivers, a respective one of said one or more RF signals to a respective one of one or more converted digital baseband signals related to said digital combination signal; and

decoding, with each one of a plurality of data signal receivers, a respective one of said one or more converted digital baseband signals to retrieve a respective one of said first plurality of digital codes.

14. The method of claim 13, wherein:

each of said first plurality of digital codes corresponds to a respective one of a plurality of global positioning system (GPS) satellites; and

said receiving a first plurality of digital codes and in response thereto providing a first plurality of digital baseband signals comprises providing a plurality of GPS signals.

15. The method of claim 13, wherein said receiving said first plurality of digital baseband signals and a plurality of digital gain control signals and in response thereto providing a second plurality of digital baseband signals comprises digitally scaling each one of said first plurality of digital baseband signals in relation to a respective one of said plurality of digital gain control signals.

16. The method of claim 13, wherein said combining said second plurality of digital baseband signals to provide a digital combination signal related to said second plurality of digital baseband signals comprises digitally summing second plurality of digital baseband signals.

17. The method of claim 13, wherein said converting said digital combination signal to one or more RF signals comprises frequency modulating a transmitter RF signal with said digital combination signal.

18. The method of claim 13, wherein said converting, with each one of a plurality of data signal receivers, a respective one of said one or more RF signals to a respective one of one or more converted digital baseband signals related to said digital combination signal comprises frequency demodulating said respective one of said one or more RF signals.

19. The method of claim 13, wherein said decoding, with each one of a plurality of data signal receivers, a respective one of said one or more digital baseband signals to retrieve a respective one of said first plurality of digital codes comprises correlating a respective one of said one or more digital baseband signals with a respective one of a second plurality of digital codes.