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Anti-aliasing filter circuit for oscilloscopes

  • US 4,621,217 A
  • Filed: 09/21/1984
  • Issued: 11/04/1986
  • Est. Priority Date: 09/21/1984
  • Status: Expired due to Fees
First Claim
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1. An anti-aliasing filter circuit for a digital oscilloscope having a controllable sweep-rate and including digitizing means for converting an analog signal to digital values for storage in said digital oscilloscope, said circuit comprising:

  • means for providing a signal input,a plurality of low pass analog filters for receiving said signal input,a digital filter for receiving said signal input, said digital filter having an electrically controllable pass band,and means for controlling the sweep-rate of said oscilloscope simultaneously with selection of signal outputs of said analog filters at higher sweep-rates and selection of the signal output of said digital filter at slower sweep-rates for coupling to said digitizing means while controlling the pass band of said digital filter at slower sweep rates in order to pass selected frequencies less than half the sampling rate of said digitizing means.

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