System for reconstruction of non-uniformly sampled signals

• US 7,403,875 B2
• Filed: 04/12/2006
• Issued: 07/22/2008
• Est. Priority Date: 04/12/2006
• Status: Expired due to Fees

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Draxelmayr, Dieter, Vogel, Christian
• Primary Examiner(s): Barlow, Jr.; John E.
• Assistant Examiner(s): Sievers; Lisa C.
• Application Number:
  US11/403,554
• Publication Number:
  US 20070244669A1
• Time in Patent Office: 832 Days
• Field of Search: 702/189
• US Class Current: 702/189
• CPC Class Codes: H03M 1/0836 of phase error, e.g. jitter
• CPC Class Codes: H03M 1/1215 using time-division multiplexing

Abstract

A signal processing system allows reconstruction of a non-uniformly sampled analog signal including sampling an analog signal at a sampling period of resulting in a quantized non-uniformly sampled signal. The non-uniformly sampled signal includes a sampled signal and an amplitude error between a signal sampled with the equidistant sample period and the non-uniformly sampled signal. A reconstructed amplitude error is determined through the time offset and the non-uniformly sampled signal, and is subtracted from the non-uniformly sampled signal. The signal processing system may be implemented in an electrocardiogram monitoring device or a mobile phone device.

Claims

1. A method that reconstructs a non-uniformly sampled analog signal, comprising:

sampling a signal, with an equidistant sample period, by at least one of an analog-digital converter or a time interleaved analog-digital converter;

determining a quantized non-uniformly sampled signal comprising the sampled signal with an amplitude error between the signal, and the non-uniformly sampled signal;

minimizing the amplitude error by determining a reconstructed amplitude error based on a time offset and the non-uniformly sampled signal, where determining a reconstructed amplitude error comprises;

differentiating the non-uniformly sampled signal; and

multiplying the non-uniformly sampled signal with a weighting factor, where the weighting factor is determined from the time offset using one or more coefficients of approximating polynomials;

delaying the non-uniformly sampled signal by a delay time needed to reconstruct the amplitude error;

subtracting the reconstructed amplitude error from the non-uniformly sampled signal to form a reconstructed non-uniformly sampled signal; and

outputting the reconstructed non-uniformly sampled signal.

2. The method according to claim 1, where determining the reconstructed amplitude error comprises delaying, by a cascade time, the subtracting of the reconstructed amplitude error from the non-uniformly sampled signal.

3. The method according to claim 1, where determining the reconstructed amplitude error comprises transforming the non-uniformly sampled signal into a discrete-fourier-transformed signal using a plurality of samples, where the plurality of samples comprises a positive integer.

4. The method according to claim 3, where determining the reconstructed amplitude error comprises determining the reconstructed amplitude error through a plurality of cascaded reconstruction steps in the frequency domain.

5. The method according to claim 1, where sampling the analog signal comprises sampling every channel by a TI-ADO with an individual time offset based on a number of channels, determining weighting factors used for the reconstruction of the amplitude error according to a number of cascaded reconstruction steps, and storing the weighting factors.

6. A signal processing apparatus that reconstructs a non-uniformly sampled analog signal, sampled by at least one of an analog-digital converter or a time interleaved analog-digital converter, comprising:

an input operable to receive an analog signal;

an output configurable to provide a digital output signal;

an evaluator operable to reconstruct and minimize an amplitude error based on a time offset and the non-uniformly sampled signal, the evaluator comprising;

a differentiator operable to differentiate the non-uniformly sampled signal; and

a multiplier operable to perform a subsequent multiplication of the non-uniformly sampled signal with a weighting factor, where the weighting factor is determined from the time offset using a plurality of coefficients of approximating polynomials;

a delay unit operable to delay the non-uniformly sampled signal by a delay time needed to reconstruct the amplitude error;

a subtract unit operable to subtract the amplitude error from the non-uniformly sampled signal to form a reconstructed non-uniformly sampled signal; and

an output configurable to output the reconstructed non-uniformly sampled signal.

7. A signal processing apparatus according to claim 6, where the evaluator is operable to execute a plurality of cascaded reconstruction steps, further comprising:

a delay unit operable to delay the non-uniformly sampled signal by a cascade time based on the cascaded reconstruction steps; and

where the subtract unit is operable to subtract the reconstructed amplitude error from the delayed non-uniformly sampled signal.

8. A signal processing apparatus according to claim 6, where the evaluator is operable to execute a reconstruction step in a frequency domain, comprising:

a transforming unit operable to transform the non-uniformly sampled signal into a discrete-fourier-transformed signal based on a plurality of samples, where the plurality of sample comprises a positive integer;

a calculator operable to determine the reconstructed amplitude error; and

a subtract unit operable to subtract the reconstructed amplitude error from the discrete-fourier-transformed signal.

9. A signal processing apparatus according to claim 8, where the evaluator is operable to execute a plurality of cascaded reconstruction steps in the frequency domain.

10. An electrocardiogram monitoring device that reconstructs a non-uniformly sampled analog signal, sampled by at least one of an analog-digital converter or a time interleaved analog-digital converter, comprising:

an input operable to receive an analog signal;

an output configurable to provide a digital output signal;

an evaluator operable to reconstruct and minimize an amplitude error based on a time offset and the non-uniformly sampled signal, the evaluator comprising;

a differentiator operable to differentiate the non-uniformly sampled signal; and

a multiplier operable to perform a subsequent multiplication of the non-uniformly sampled signal with a weighting factor, where the weighting factor is determined from the time offset using a plurality of coefficients of approximating polynomials;

a delay unit operable to delay the non-uniformly sampled signal by a delay time needed to reconstruct the amplitude error;

a subtract unit operable to subtract the amplitude error from the non-uniformly sampled signal to form a reconstructed non-uniformly sampled signal; and

an output configurable to output the reconstructed non-uniformly sampled signal.

11. A mobile phone that reconstructs a non-uniformly sampled analog signal, sampled by at least one of an analog-digital converter or a time interleaved analog-digital converter, comprising:

an input operable to receive an analog signal;

an output configurable to provide a digital output signal;

an evaluator operable to reconstruct and minimize an amplitude error based on a time offset and the non-uniformly sampled signal, the evaluator comprising;

a differentiator operable to differentiate the non-uniformly sampled signal; and

a multiplier operable to perform a subsequent multiplication of the non-uniformly sampled signal with a weighting factor, where the weighting factor is determined from the time offset using a plurality of coefficients of approximating polynomials;

a delay unit operable to delay the non-uniformly sampled signal by a delay time needed to reconstruct the amplitude error;

a subtract unit operable to subtract the amplitude error from the non-uniformly sampled signal to form a reconstructed non-uniformly sampled signal; and

an output configurable to output the reconstructed non-uniformly sampled signal.

12. A computer program product comprising:

a computer useable medium having computer readable code embodied in the medium, the computer readable code comprising;

computer readable code executable to sample a signal by a at least one of a analog-digital converter or a time interleaved analog-digital converter;

computer readable code executable to determine a quantized non-uniformly sampled signal comprising a sampled signal and an amplitude error between a signal sampled with an equidistant sample period and the non-uniformly sampled signal;

computer readable code executable to minimize the amplitude error by determining a reconstructed amplitude error based on the time offset and the non-uniformly sampled signal, where determining a reconstructed amplitude error comprises differentiating the non-uniformly sampled signal and multiplying the non-uniformly sampled signal with a weighting factor, where the weighting factor is determined from the time offset using a plurality of coefficients of approximating polynomials;

computer readable code executable to subtract the reconstructed amplitude error from the non-uniformly sampled signal to form a reconstructed non-uniformly sampled signal and;

computer readable code executable to output the reconstructed non-uniformly sampled signal.

13. A signal processing apparatus that reconstructs a non-uniformly sampled analog signal, sampled by at least one of an analog-digital converter or a time interleaved analog-digital converter, a sampling period comprises a period, comprising:

input means for receiving an analog signal;

means for providing a digital output signal;

evaluation means for reconstructing and minimizing an amplitude error based on the time offset and the non-uniformly sampled signal, the evaluation means comprising;

differentiating means for differentiating the non-uniformly sampled signal; and

multiplying means for multiplying the non-uniformly sampled signal with a weighting factor, where the weighting factor is determined from the time offset using a plurality of coefficients of approximating polynomials;

delay means for delaying the non-uniformly sampled signal by a delay time needed to reconstruct the amplitude error;

subtraction means for subtracting the amplitude error from the non-uniformly sampled signal to form a reconstructed non-uniformly sampled signal; and

means for outputting the reconstructed non-uniformly sampled signal.

14. A method that reconstructs a non-uniformly sampled analog signal, comprising:

determining a quantized non-uniformly sampled signal comprising a sampled signal and an amplitude error between a signal and the non-uniformly sampled signal, where the signal is sampled with an equidistant sample period;

minimizing the amplitude error by determining a reconstructed amplitude error based on a time offset and the non-uniformly sampled signal, where determining the reconstructed amplitude error comprises;

differentiating the non-uniformly sampled signal; and

multiplying the non-uniformly sampled signal with a weighting factor, where the weighting factor is determined from the time offset using one or more coefficients of approximating polynomials;

delaying the non-uniformly sampled signal by a delay time needed to reconstruct the amplitude error; and

subtracting the reconstructed amplitude error from the non-uniformly sampled signal to form a reconstructed non-uniformly sampled signal.