Method for Reconstructing an Electrical Signal

• US 20080281559A1
• Filed: 08/24/2005
• Published: 11/13/2008
• Est. Priority Date: 10/05/2004
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Frey, Bernd, Iske, Burkhard
• Granted Patent: US 7,620,524 B2
• Time in Patent Office: Days
• US Class Current: 702/189
• CPC Class Codes: G01R 19/2506 Arrangements for conditioning or analysing measured signals, e.g. for indicating peak values G01R19/003 takes precedence; Details concerning sampling, digitizing or waveform capturing displaying waveforms G01R13/00; analog sampling G01R19/0053
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements

Abstract

A method for reconstructing an electrical signal in which the signal and a second signal, which is related to the first signal according to a predefined function, are sampled at a predefined sampling rate. The occurrence of aliasing in a downstream digital low-pass filter may be substantially reduced if missing sampling values of the first signal are calculated from the sampling values of the second signal with the aid of the known function.

Claims

1-15. -15. (canceled)

16. A method for reconstructing an analog electrical signal, the method comprising:

sampling a first analog electrical signal and a second analog electrical signal, which are related according to a predefined function, at a predefined sampling rate;

generating corresponding sampling values, wherein in time segments in which no valid sampling values may be generated from the first signal; and

calculating the sampling values of the first signal from the sampling values of the second signal by taking into account the predefined function.

17. The method of claim 16, wherein the first signal is a current signal and the second signal is a voltage signal.

18. The method of claim 16, wherein the missing sampling values are calculated with a function deltaI=deltaU/Ri.

19. The method of claim 16, wherein the sampling values of the first signal are calculated also in time segments in which the first signal is valid.

20. The method of claim 19, wherein the difference between (i) the calculated sampling values and at least one of (ii) the measured sampling values and the values derived from the measured sampling values, are ascertained and compared with a threshold value.

21. The method of claim 20, wherein, if the difference is less than the threshold value, the first signal is reconstructed in the invalid segments based on the second signal and, if the difference exceeds the threshold value, the system switches over to another interpolation method.

22. A device for reconstructing of an analog electrical signal, comprising:

a first signal source to generate a first electrical signal;

a second signal source to generate a second electrical signal, the first and second electrical signals being related according to a predefined function;

a sampling device to sample the first signal and the second signal; and

a computing device, to which sampling values of the second signal are supplied, to calculate sampling values of the first signal from the sampling values of the second signal, taking into account the known function.

23. The device of claim 22, wherein at the output of the computing device a switch is provided by which the calculated sampling values are supplied for further digital processing in predefined time segments.

24. The device of claim 22, further comprising:

a low-pass filter which is connectable optionally to one of the sampling device and the computing device with the switch.

25. The device of claim 22, wherein the first signal source is a current sensor and the second signal source is a voltage sensor.

26. The device of claim 22, further comprising:

a low-pass filter to filter the sampling values of the first signal; and

another low-pass filter to filter the sampling values of the second signal.

27. The device of claim 26, wherein an algorithm is used to calculate a predefined quantity from the filtered sampling values.

28. The device of claim 22, wherein the computing device calculates sampling values of the first signal also in time segments in which the first signal is valid.

29. The device of claim 28, wherein the difference between the reconstructed sampling values and the measured sampling values is ascertained and compared with a threshold value.

30. The device of claim 29, wherein the first signal is reconstructed in the invalid segments based on the second signal if the difference is less than the threshold value, and the system switches over to another interpolation method if the difference exceeds the threshold value.