| CPC H04B 1/10 (2013.01) | 12 Claims |
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1. An apparatus for correcting an input signal, configured for
transmitting an ultrasonic signal from an ultrasonic transceiver during a first time span,
receiving an ultrasonic signal during a second time span,
receiving the input signal from the transceiver, the received input signal comprising a time series of input values of the ultrasonic signal received during the second time span,
matching a series of template values to the time series of input values by warping the series of template values and the time series of input values relatively to each other so as to assign one or more template values to one or more input values,
wherein the series of template values represents an approximation of a noise signal that is expected to be comprised in the input signal, and wherein the time series of input values and the series of template values cover a time span of a ringing of the ultrasonic transceiver after transmitting the ultrasonic signal,
obtaining a series of corrected input values based on a mismatch between the input values and their respective assigned template values, and
providing a corrected signal based on the series of corrected input values,
applying a frequency filter to the series of corrected input values, and wherein the frequency filter is configured for outputting a signal with a frequency within a range of ±5% of a frequency of the transmitted ultrasonic signal and configured for attenuating signals with frequencies outside of the range, and
obtaining information about time of flight of the ultrasonic signal by evaluating the filtered corrected signal.
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