Real-time time encoding and decoding machines

• US 9,014,216 B2
• Filed: 11/30/2009
• Issued: 04/21/2015
• Est. Priority Date: 06/01/2007
• Status: Expired due to Fees

• Current Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Original Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Inventors: Lazar, Aurel A., Simonyi, Erno K., Toth, Laszlo T.
• Primary Examiner(s): Phung, Luat
• Application Number:
  US12/628,067
• Publication Number:
  US 20100303101A1
• Time in Patent Office: 1,968 Days
• Field of Search: 370/521, 375/216, 375/316, 341/110, 341/155
• US Class Current: 370/521
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: H03M 1/125 Asynchronous, i.e. free-running operation within each conversion cycle
• CPC Class Codes: H03M 1/50 with intermediate conversion to time interval H03M1/64 takes precedence
• CPC Class Codes: H03M 1/82 with intermediate conversion to time interval
• CPC Class Codes: H03M 3/432 the quantiser being a pulse width modulation type analogue/digital converter, i.e. differential pulse width modulation
• CPC Class Codes: H03M 3/502 Details of the final digital/analogue conversion following the digital delta-sigma modulation

Abstract

Methods for decoding a signal encoded by a Time Encoding Machine (TEM) include defining a plurality of time-windows, each time-window corresponding to a portion of a TEM-encoded signal and made up of a plurality of trigger values, at least two of the time-windows overlapping, decoding each of the time-windows using a Time Decoding Machine (TDM) to generate a decoded time-window, and stitching the decoded time-windows together to generate a TEM-decoded signal.

Claims

1. A circuit for decoding a signal encoded by a Time Encoding Machine (TEM) comprising:

a Time Decoding Machine (TDM) for decoding a portion of a TEM-encoded signal, the TEM-encoded signal comprising a plurality of action potentials encoded in a time sequence, said TDM comprising a TDM-input and a TDM-output, said TDM-input for receiving the portion of the TEM-encoded signal over a first time-window, said TDM-output for transmitting a decoded approximated signal over said first time-window; and

a stitching circuit, having a stitching-input connected to said TDM-output, said stitching circuit combining said decoded approximated signal over said first time-window with at least one other decoded approximated signal over a second time-window, wherein said first time-window and said second time-window overlap.

2. The circuit of claim 1 wherein said TDM calculates a value of said TEM-encoded signal, u, over said first time-window, [t_i, t_i+N], wherein the value of u at a given time, t, is approximated by solving for periodic bandlimited signal

3. The circuit of claim 2 wherein

4. The circuit of claim 2 wherein said coefficients [d_i]_n=d_i,n are recovered by solving equation V_i^H V_id_i=V_i^H D_iPq_i, where V_i^H is a conjugate transposition of V_i,

[V_i]_nm=e^jm2Ω

i^i+n/N is a Vandermonde matrix,

D_i=diag(e<sup>jΩ

ii+n</sup>) is a diagonal matrix,

P is an upper triangular matrix with values [P]_nm=1 and [P]_nm=0 for n<

m+1 and n≧

m+1, respectively and

[q_i]_n=q_l+n, for all n, m=0, . . . , N.

5. The circuit of claim 2, wherein said first and second time-windows, ω

_n, are defined by a function

6. The circuit of claim 5, wherein said stitching circuit combines said first and second time-windows by solving equation

7. The circuit of claim 1 further comprising a post-filtering circuit connected to an output of said stitching circuit for receiving a combined TEM-decoded signal, said post-filtering circuit removing an approximate error, e[k]=u(kS)−

û

(kS), from said combined TEM-decoded signal of said stitching circuit by solving for an equation

8. A method for decoding a signal encoded by a Time Encoding Machine (TEM) comprising:

defining a plurality of time-windows, each time-window corresponding to a portion of a TEM-encoded signal and comprising a plurality of trigger values, the TEM-encoded signal comprising a plurality of action potentials encoded in a time sequence, at least two of said time-windows overlapping;

decoding each of said time-windows using a Time Decoding Machine (TDM) to generate a decoded time-window; and

stitching said decoded time-windows together to generate a TEM-decoded signal.

9. The method of claim 8 wherein each of said time-windows overlaps with at least one other time-window.

10. The method of claim 8 wherein said TDM calculates a value of said TEM-encoded signal, u, over one of said plurality of time-windows, [t_i, t_i+N], where the value of u at a given time, t, is approximated by solving for periodic bandlimited signal

11. The method of claim 10 wherein

12. The method of claim 10 wherein said coefficients [d_i]_n=d_i,n are recovered by solving equation V_i^HV_id_i=V_i^HD_iPq_i, where V_i^H is a conjugate transposition of V_i,

[V_i]_nm=e^jm,2Ω

i^i+n/N is a Vandermonde matrix,

D_i=diag(e<sup>jΩ

ii+n</sup>) is a diagonal matrix,

P is an upper triangular matrix with values [P]_nm=1 and [P]_nm=0 for n<

m+1 and n≧

m+1, respectively and

[q_i]_n=q_i+n, for all n, m=0, N.

13. The method of claim 10, wherein said time-windows, ω

_n, are defined by a function

14. The method of claim 13, wherein said stitching comprises adding said time-windows by solving equation

15. The method of claim 8 further comprising post-filtering said TEM-decoded signal by removing an approximate error, e[k]=u(kS)−

û

(kS), from said TEM-decoded signal by solving for an equation