Systems and methods for analog to digital converter failure identification

1. An analog to digital (A/D) conversion system with failure identification, comprising:

an amplifier configured to receive an input and produce an amplified output injected with at least one identifiable characteristic;

an A/D converter configured to receive the amplified output and convert the output to a digital output;

a failure identification module configured to determine the existence, non-existence, or variation of the identifiable characteristic in the digital output;

a filter configured to filter the digital output to remove the identifiable characteristic from the digital output; and

an alert module configured to provide a failure notification based on a determination by the failure identification module that the identifiable characteristic does not exist in the digital output, or has changed in a manner indicative of an A/D failure and/or amplifier failure.

2. The A/D conversion system of claim 1 , wherein the amplifier is chopper stabilized.

3. The A/D conversion system of claim 1 , wherein the amplifier comprises a chopper amplifier.

4. The A/D conversion system of claim 3 , wherein the frequency characteristic associated with the amplifier comprises a chopping frequency of the chopper amplifier.

5. The A/D conversion system of claim 1 , wherein the failure identification module is configured to determine that the frequency characteristic is missing or exhibits significant variation based on a frequency domain analysis of a fast Fourier transform of the output of the A/D converter.

6. The A/D conversion system of claim 1 , wherein the frequency characteristic associated with the amplifier comprises at least one injected frequency tone.

7. An intelligent electronic device (IED) configured to identify a failure in an analog to digital (A/D) converter, comprising:

a meter configured to:

identify a frequency characteristic injected by an amplifier into an input of an A/D converter, wherein the input to the amplifier comprises a frequency f a , and the output of the amplifier comprises f a +f c , where f c is the injected frequency characteristic; and

obtain a measurement of an output of the A/D converter;

a frequency characteristic module configured to determine that the frequency characteristic, f c , is missing or exhibits significant variation from the output of the A/D converter; and

an error reporting module configured to report a failure of the A/D converter based on the determination that the frequency characteristic, f c , is missing or exhibits significant variation from the output of the A/D converter.

8. The IED of claim 7 , wherein the frequency characteristic identified by the meter corresponds to a chopping frequency of a chopper-stabilized amplifier.

9. The IED of claim 7 , wherein the meter is configured to identify the frequency characteristic by accessing a stored value corresponding to a known chopping frequency of a chopper amplifier.

10. The IED of claim 7 , wherein the meter is configured to identify the frequency characteristic by measuring a chopping frequency of a chopper amplifier.

11. The IED of claim 10 , wherein the meter is configured to measure the chopping frequency of a chopper amplifier by comparing an input and an output of the chopper amplifier.

12. The IED of claim 7 , wherein the frequency characteristic module is configured to determine that the frequency characteristic is missing or exhibits significant variation based on a frequency domain analysis of a fast Fourier transform of the output of the A/D converter.

13. The IED of claim 7 wherein the frequency characteristic associated with the amplifier comprises at least one injected frequency tone.

14. A method for verifying a digital output of an analog to digital (A/D) converter, comprising:

receiving, by an amplifier, an analog input;

producing, by the amplifier, an amplified analog output that corresponds to the analog input and includes an injected identifiable characteristic;

generating, via an A/D converter, a digital output corresponding to the amplified analog output;

confirming, via a verification module, that the digital output generated by the A/D converter includes the identifiable characteristic;

filtering the digital output to remove the injection signal; and

outputting the filtered digital signal as a verified digital output signal based on the confirmation that the digital output includes the injection signal.

15. The method of claim 14 , wherein the gain of the amplifier is greater than, less than, or equal to unity.

16. The method of claim 14 , wherein the amplified analog output is inherently injected with the identifiable characteristic based on the type of amplifier used.

17. The method of claim 14 , wherein the amplified analog output is injected with the identifiable characteristic via a separate injection circuit.

18. The method of claim 14 , wherein the amplifier comprises a chopper amplifier and wherein the injected identifiable characteristic comprises a chopping frequency inherently injected by the chopper amplifier.

19. The method of claim 14 , wherein confirming that the digital output generated by the A/D converter includes the identifiable characteristic comprises the use of a frequency domain analysis using a fast Fourier transform.

20. The method of claim 14 , wherein the verification module is part of an intelligent electronic device configured to monitor the A/D converter, and

wherein a failure to confirm that the digital output generated by the A/D converter includes the identifiable characteristic results in the further method step of:

reporting a failure of the A/D converter.