Sensor arrangement with variable carrier frequency and Goertzel filtering

Patent metadata

Field	Value
Publication number	US-10181971-B2
Application number	US-201515313241-A
Country	US
Kind code	B2
Filing date	May 20, 2015
Priority date	May 26, 2014
Publication date	Jan 15, 2019
Grant date	Jan 15, 2019

Abstract

A method for processing a signal modulated with a variable carrier frequency includes calculating a coefficient for demodulation of the signal. The method also includes demodulating the signal by calculating discrete intermediate values utilizing the coefficient for a predefined maximum number of steps and calculating the signal with the aid of the intermediate values of the coefficient. The value of the coefficient is respectively calculated on the basis of carrier frequencies for each step.

First claim

The invention claimed is:

1. A method for processing a signal modulated with a variable carrier frequency, comprising:
calculating a coefficient (c(n)) for demodulation of the signal,
demodulating the signal by calculating discrete intermediate values (s, s1, s2) utilizing the coefficient for a predefined maximum number of steps (n_max), and
calculating the signal with the aid of the intermediate values and the coefficient (c(n)),
wherein the value of the coefficient (c(n)) is respectively calculated on the basis of carrier frequencies (f_signal(n)) for each sampling step from a first step to the predefined maximum number of steps (n_max), and
wherein the modulation of the signal is carried out by using precalculated values of the coefficient and calculated utilizing the following procedure
s 1=0
s 2=sin(2π f _signal/ f _sample)

repeat with n from 1 to n_max
s=c ( n )* s 1− s 2

s 2= s 1
s 1= s
signal( n )= s

end
wherein f_signal is the carrier frequency or instantaneous frequency for the nth sampling step, and f_sample is a sampling frequency.

2. The method as set forth in claim 1 , wherein the coefficient is calculated as a function of the instantaneous frequency (f_signal(n)) of the carrier frequencies.

3. The method as set forth in claim 1 , wherein at least one bandwidth of the carrier frequencies is predefined, the bandwidth lying outside predictable perturbation frequencies.

4. The method as set forth in claim 2 , wherein a bandwidth of the carrier frequencies is predefined, the bandwidth being established as a function of a frequency or frequency bandwidth of the signal.

5. The method as set forth in claim 1 , wherein the signal is modulated with a modulation unit, and in that the processing of the modulated signal is carried out with a signal processing unit, the carrier frequencies or instantaneous frequencies being synchronized between the modulation unit and the signal processing unit.

6. The method as set forth in claim 1 , further comprising storage of the values of the coefficient in a nonvolatile memory.

7. The method as set forth in claim 1 , further comprising storage of identical coefficient values in a memory location.

8. The method as set forth in claim 1 , wherein the coefficients are calculated utilizing the equation
c ( n )=2 cos(2π* f _signal( n )/ f _sample), where

n=sampling step
c(n)=coefficient for the sampling step n
f_signal(n)=carrier frequency or instantaneous frequency for the nth sampling step
f_sample=sampling frequency.

9. The method as set forth in claim 1 , wherein the intermediate values are calculated by utilizing the following procedure
s 1=0
s 2=0
repeat with n from 1 to n_max
s =signal( n )+ c ( n )* s 1− s 2

s 2= s 1
s 1= s

end, where
s, s1, s2=intermediate values of different sampling steps
signal(n)=modulated signal value in step n
n_max=total number of sampling steps for a procedure.

10. The method as set forth in claim 1 , wherein an amplitude of the signal is calculated utilizing the equation
A= 2*sqrt( s 2* s 2+ s 1* s 1− c ( n _max)* s 1* s 2)/ n _max, where:

s1, s2=intermediate values after n_max steps
c(n_max)=coefficient value at step n_max.

11. A sensor arrangement, comprising:
a modulation unit for modulating a sensor signal, wherein the modulation of the signal is carried out by using precalculated values of a coefficient and calculated utilizing the following procedure
s 1=0
s 2=sin(2π· f _signal/ f _sample)

repeat with n from 1 to n_max
s=c ( n )* s 1− s 2

s 2= s 1
s 1= s
signal( n )= s

end,
wherein f_signal is a carrier frequency or instantaneous frequency for the nth sampling step, and f_sample is a sampling frequency,

a sensor element for generating the sensor signal, and
a signal processing unit comprising
a coefficient block configured to continuously calculate a plurality of values of the coefficient (c(n)) for demodulating the signal,
a summation element configured to demodulate the signal by calculating discrete intermediate values using the coefficient (c(n)) for a predefined maximum number of steps (n_max) and calculating the signal with the aid of the intermediate values and the coefficient (c(n)),
at least one intermediate memory for storing the intermediate values, one of the intermediate memories being connected to the coefficient block, and
a multiplier for multiplying one discrete intermediate value by the coefficient (c(n)) to generate a sum, the sum being deliverable to the summation element.

Assignees

• Continental Teves Ag & Co Ohg

Inventors

• Acker Heinrich

Classifications

• H04L27/2639

  Modulators using other transforms, e.g. discrete cosine transforms, Orthogonal Time Frequency and Space [OTFS] or hermetic transforms · CPC title

• H04B1/30

  for homodyne or synchrodyne receivers (demodulator circuits H03D1/22) · CPC title

• G01D3/02 Primary

  with provision for altering or correcting the law of variation · CPC title

• H04L25/06

  DC level restoring means; Bias distortion correction {; Decision circuits providing symbol by symbol detection} · CPC title

• G06F17/14 Primary

  Fourier, Walsh or analogous domain transformations {, e.g. Laplace, Hilbert, Karhunen-Loeve, transforms (for correlation function computation G06F17/156; spectrum analysers G01R23/16)} · CPC title