Boots – shoes – and leggings
Patent
1994-02-07
1996-08-13
Voeltz, Emanuel T.
Boots, shoes, and leggings
364574, G06F 1531
Patent
active
055463320
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
In many areas of measuring technology and data acquisition, a desired wanted signal is superimposed with an undesired disturbing signal. This phenomenon is generally referred to as interference. It is often not possible to achieve an adequate reduction in the effect of the disturbing signal by suitable modification of the physical measuring conditions. In such cases, it is attempted to compensate for the interference after the data acquisition by methods of adaptive digital signal processing in the measurement signal with the incorporation of a reference signal of the disturbance (interference compensation). A particular difficulty occurs if significant proportions of the disturbance are not contained in the reference signal. In such cases, the known processes for adaptive interference compensation fail.
FIG. 1 shows in a diagrammatic way the previously known approach to interference compensation (B. Widrow and S. D. Stearns: "Adaptive Signal Processing", Prentice-Hall, Englewood Cliffs, N.J., 1985). In the case of these known processes, it is assumed that an "observation" of the disturbing signal is available in the form of a reference signal n'. An adaptive filter forms a linear or nonlinear combination of a number of temporally successive values of the reference signal n'. This adaptively preprocessed reference signal is then subtracted from the disturbed measurement signal s+n. The parameters of the linear or nonlinear adaptive filter are in this case set such that the energy of the output signal E assumes a minimum. Consequently, the disturbing signal component in the output signal is minimized in accordance with the method of least squares (B. Widrow 1985).
The classical approach to interference compensation hereby described is based on the implicit assumption that all the components of the interference can be represented by suitable linear or nonlinear compensations of a reference signal. The classical approach fails, or supplies inadequate compensation results, if this prerequisite is not met, i.e. if significant components of the disturbance are not depicted in the reference signal.
SUMMARY OF THE INVENTION
In those cases in which the reference signal does not supply reliable information on the true progression of the interference, reliable information on the signal form of the interference must be obtained in another way. The invention is based on the object of specifying a process for interference compensation for a special case of interference, the case of so-called quasi-periodic interference, that is to say an interference signal characteristic which recurs periodically, both the period and the signal form being subject to stochastic variations.
This object is achieved by a process for separating a wanted signal, contained in a measurement signal, from a disturbing signal, likewise contained in this measurement signal.
In general terms the steps of the process of the present invention are as follows:
a) determination of a series of trigger instants from an auxiliary signal;
b) estimation of a disturbing signal template by trigger-synchronous averaging of the measurement signal;
c) generation of a trigger-synchronous reference signal from the disturbing signal template; and
d) filtering of the measurement signal with the aid of the trigger-synchronous reference signal.
In the case of quasi-periodic interference, there is namely usually an auxiliary signal available, from which the instantaneous period of the interference can be derived. Such an auxiliary signal can often be derived from a further measurement signal. In medical applications, it may be derived, for example, from the electro-cardiogram or electro-encephalogram. In the case of other applications, such an auxiliary signal can be derived under certain circumstances from the measurement signal itself by suitable trigger circuits. Consequently, the repetition instances of the interference signal in the measurement signal are known. An estimation of the signal characteristic of the interference is then o
REFERENCES:
patent: 4964411 (1990-10-01), Johnson et al.
patent: 5029118 (1991-07-01), Nakajima et al.
patent: 5152172 (1992-10-01), Leon et al.
"Canceling the Cardiogenic Artifact in Impedance Pneumography", A. V. Sahakian et al, IEEE Seventh Annual Conference of the Engineering in Medicine & Biology Society, (1985), New York, pp. 855-859.
"Adaptive Filtering of Evoked Potentials", N. V. Thakor, IEEE Transactions on Biomedical Engineering, vol. 34, No. 1, Jan. 1987, New York, pp. 6-12.
"Adaptive Noise Canceling for Speech Signals", M. R. Sambur, IEEE Transactions on Acoustics, Speech and Signal Processing, vol. 26, No. 5, Oct. 1978, pp. 419-423.
Kemper M.
Siemens Aktiengesellschaft
Voeltz Emanuel T.
LandOfFree
Process for compensating for quasi-periodic disturbances of meas does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for compensating for quasi-periodic disturbances of meas, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for compensating for quasi-periodic disturbances of meas will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1054148