Frequency extension methods and apparatus for low-frequency electronic instrumentation

1. An electronic measuring system, comprising:

an electronic measuring instrument; and

a plurality of downconverting frequency extenders from which two or more downconverting frequency extenders can be selected and configured in series between a test signal output of a device under test (DUT) and a measuring input of said electronic measuring instrument, to selectively and effectively extend the permissible input frequency range of said electronic measuring instrument.

2. The electronic measuring system of claim 1 wherein each downconverting frequency extender of said plurality of downconverting frequency extenders has its own unique housing.

3. The electronic measuring system of claim 2 wherein each downconverting frequency extender of said plurality of downconverting frequency extenders has its own local oscillator.

4. The electronic measuring system of claim 3 wherein each downconverting frequency extender of said plurality of downconverting frequency extenders includes connectors that allow a selected downconverting frequency extender to be physically and electrically cascaded with one or more other selected downconverting frequency extenders between a test signal output of the DUT and the measuring input of said electronic measuring instrument.

5. The electronic measuring system of claim 4 wherein one or more of said plurality of downconverting frequency extenders each includes a phase-locked loop (PLL) and a reference signal connector, and each selected downconverting frequency extender having a PLL and reference signal connector is configured to generate a local oscillator signal having a phase related to a phase of a reference signal provided by said electronic measuring instrument.

6. The electronic measuring system of claim 1 wherein said plurality of downconverting frequency extenders comprises a kit or a system especially made or adapted for use with said electronic measuring instrument.

7. The electronic measuring system of claim 1 , further comprising a plurality of upconverting frequency extenders from which one or more upconverting frequency extenders can be selected to selectively and effectively extend the maximum output frequency range of a signal generator.

8. The electronic measuring system of claim 7 wherein each upconverting frequency extender has its own local oscillator, its own separate housing, and connectors that allow two or more selected upconverting frequency extenders to be physically and electrically cascaded between a signal output of a signal generator and an input of a device under test.

9. A system for extending the effective input frequency range of an electronic instrument, comprising:

a first downconverting frequency extender operable to downconvert a test signal having a frequency higher than a maximum measuring input frequency of an electronic measuring instrument to a first downconverted test signal; and

a second downconverting frequency extender connectable in series with said first downconverting frequency extender operable to downconvert said first downconverted test signal to a second downconverted test signal having a frequency within a permissible measuring input frequency range of the electronic measuring instrument.

10. The system of claim 9 wherein said first and second downconverting frequency extenders each has its own separate housing.

11. The system of claim 10 wherein said first and second downconverting frequency extenders each includes its own local oscillator.

12. The system of claim 11 wherein said first and second downconverting frequency extenders include connectors that allow said first and second downconverting frequency extenders to be physically and electrically cascaded between a test signal output of a device under test and a measuring input of the electronic measuring instrument.

13. The system of claim 9 wherein one or both of said first and second downconverting frequency extenders are configured to generate said first and second downconverted test signals using a local oscillator signal having a phase that is related to a phase of a reference signal received from the electronic measuring instrument.

14. The system of claim 9 wherein said first and second downconverting frequency extenders include connectors that allow said first and second downconverting frequency extenders to be physically and electrically cascaded and connected between a test signal output of a device under test and a measuring input of the electronic measuring instrument.

15. The system of said claim 14 wherein one or both of said first and second downconverting frequency extenders each further includes:

a reference signal input configured to receive a reference signal from the electronic measuring instrument; and

a phase-locked loop configured to generate a local oscillator signal having a phase related to a phase of the received reference signal.

16. A frequency extending kit comprising a plurality of downconverting frequency extending units (FEU-Ds) from which one or more downconverting FEU-Ds can be selected to selectively and effectively extend the permissible input frequency range of an electronic measuring instrument, each downconverting FEU-D having its own local oscillator (LO), its own separate housing, and connectors that allow two or more selected downconverting FEU-Ds to be physically and electrically cascaded between a test signal output of a device under test (DUT) and a measuring input of the electronic measuring instrument.

17. The frequency extending kit of claim 16 wherein one or more downconverting FEU-Ds of said plurality of downconverting FEU-D each further includes:

a reference signal input configured to receive a reference signal from the electronic measuring instrument; and

a phase-locked loop configured to generate a local oscillator signal having a phase related to a phase of the received reference signal.

18. The frequency extending kit of claim 16 , further comprising a plurality of upconverting frequency extending units (FEU-Us) from which one or more upconverting FEU-Us can be selected to extend the output frequency range of a signal generator, each upconverting FEU-U having its own LO, its own separate housing, and connectors that allow two or more selected upconverting FEU-Us to be physically and electrically cascaded between an output of the signal generator and an input of the DUT.

19. The frequency extending kit of claim 18 wherein one or more downconverting FEU-Ds of said plurality of downconverting FEU-Ds each further includes:

a reference signal input configured to receive the reference signal from the electronic measuring instrument; and

a phase-locked loop configured to generate a local oscillator signal having a phase related to a phase of the received reference signal.

20. The frequency extending kit of claim 19 wherein one or more upconverting FEU-Us of said plurality of upconverting FEU-Us each further includes:

a reference signal input configured to receive a reference signal from the electronic measuring instrument; and

a phase-locked loop configured to generate a local oscillator signal having a phase related to a phase of the received reference signal.

21. A frequency extending kit comprising a plurality of upconverting frequency extending units (FEU-Us) from which one or more upconverting FEU-Us can be selected to extend the output frequency range of a signal generator, each upconverting FEU-U having its own LO, its own separate housing, and connectors that allow two or more selected upconverting FEU-Us to be physically and electrically cascaded between an output of the signal generator and an input of the DUT.

22. The frequency extending kit of claim 21 wherein one or more upconverting FEU-Us of said plurality of upconverting FEU-Us each further includes:

a reference signal input configured to receive the reference signal from the electronic measuring instrument; and

a phase-locked loop configured to generate a local oscillator signal having a phase related to a phase of the received reference signal.