Signal processing method and an evaluation circuit

Abstract

The invention relates to a method and to an apparatus for the processing of a received signal of an optoelectronic sensor, in particular of a light grid having a plurality of reception channels, with a comparison being carried out between the received signal and a signal delayed with respect to the received signal and the signal obtained by the comparison being supplied to a further processing.

1 - 12 . (canceled)  
   
   
       13 . A method for the processing of a received signal of an optoelectronic sensor, in particular of a light grid, characterized in that the received signal is supplied with delays which differ from one another and with direct components which differ from one another to the two inputs of a comparator circuit ( 2 ); and in that the comparator circuit ( 2 ) transmits a detection signal which indicates when the one signal applied to the comparator circuit ( 2 ) is larger than the other.  
   
   
       14 . A method in accordance with  claim 13 , characterized in that the difference in the two delays corresponds approximately to half the individual pulse width of the received signal.  
   
   
       15 . A method in accordance with  claim 13 , characterized in that the received signal is amplified to substantially the same degree in the two input branches of the comparator circuit ( 2 ).  
   
   
       16 . A method in accordance with  claim 13 , characterized in that the output signal of the comparator circuit ( 2 ) is used for the further processing.  
   
   
       17 . A method in accordance with claim  1 , characterized in that the individual pulses of the received signal are substantially sinusoidal.  
   
   
       18 . A method in accordance with  claim 13 , characterized in that the individual pulses of the received signal are substantially sinusoidal.  
   
   
       19 . A method in accordance with claim  3 , characterized in that the output signal of a difference amplifier, to which a differential signal produced by the optoelectronic sensor is applied, is used as the received signal.  
   
   
       20 . A method in accordance with  claim 13 , characterized in that the output signal of a difference amplifier, to which a differential signal produced by the optoelectronic sensor is applied, is used as the received signal.  
   
   
       21 . An evaluation circuit for the processing of a received signal of an optoelectronic sensor, in particular of a light bid, characterized in that the received signal is applied via a first and a second signal branch to a respective input of a comparator ( 2 ), wherein at least one signal branch has a delay circuit ( 3 ;  5 ,  6 ) which causes the received signal to be applied to the two inputs of the comparator ( 2 ) with delays different from one another; and wherein at least one signal branch has an offset circuit ( 4 ;  6 ) which causes the received signal to be applied to the two inputs of the comparator ( 2 ) with direct components which differ from one another, the output signal of the comparator acting on a further processing circuit.  
   
   
       22 . An apparatus in accordance with  claim 21 , characterized in that the delay circuit ( 3 ;  5 ,  6 ) arid the offset circuit are provided in the same signal branch.  
   
   
       23 . An apparatus in accordance with  claim 22 , characterized in that the delay circuit and the offset circuit are realized by an all pass filter ( 5 ) connected in series with a low pass filter ( 6 ).  
   
   
       24 . An apparatus in accordance with  claim 23 , characterized in that the all pass filter ( 5 ) is formed as an all pass filter of the 2nd order with an integrated inverter.  
   
   
       25 . An. apparatus in accordance with  claim 23 , characterized in that the low pass filter ( 6 ) has an integrated inverter.  
   
   
       26 . An apparatus in accordance with  claim 23 , characterized in that the low pass filter ( 6 ) is connected after the all pass filter.  
   
   
       27 . (canceled)