Amplitude- and rise-time-compensated filters

Claim 2

An amplitude-compensated, rise-time-compensated filter for converting an input pulse, having a substantially linear leading edge, to a bipolar output pulse, the filter comprising, differentiator means for differentiating the input pulse; and subtractor means for subtracting a pulse directly proportional to the input pulse from the differentiated input pulse, to form an output pulse having a fixed zero crossing time relative to the time of occurance of the input pulse that is invariant with the amplitude or rise time of the input pulse.

Claim 3

The filter of claim 1, wherein said subtractor means comprises means for obtaining a fraction of the input pulse and differencing means for obtaining the difference between the differentiated input pulse and the fraction of the input pulse.

Claim 4

The filter of claim 2, wherein said means for obtaining a fraction of the input pulse comprises a divider network.

Claim 5

The filter of claim 2, wherein said differencing means comprises a differential amplifier having a first input operatively connected with said differentiator means and a second input operatively connected with said means for obtaining a fraction of the input pulse.

Claim 6

The filter of claim 1, wherein said differentiator means comprises an RC differentiator network.

Claim 7

The filter of claim 1, further comprising low-pass filter means for passing the frequencies of the input pulse.

Claim 8

The filter of claim 6, wherein said low-pass filter means is a separate filter section following the subtractor means.

Claim 9

The filter of claim 6, wherein said low-pass filter means precedes said differentiator means.

Claim 10

The filter of claim 1, wherein said subtractor means comprises means for reversing the polarity of the input pulse to obtain a pulse equal in magnitude, but of opposite polarity, means for obtaining a fraction of the opposite polarity pulse, and means for summing the opposite polarity pulse with the differentiated input pulse to obtain the output pulse.

Claim 11

The filter of claim 9, wherein said means for reversing the polarity of the input pulse comprises a balanced-output amplifier having an input-terminal means for receiving the input pulse, and positive and negative output terminals, the positive terminal operatively connected with said differentiating means and the negative terminal operatively connected to said means for obtaining a fraction of the opposite polarity pulse.

Claim 12

An amplitude-compensated, rise time-compensated filter for receiving an input pulse having a substantially linear leading edge and non-zero rise time and for converting said input pulse to a bipolar output pulse having a zero-crossing time that is independent of the amplitude and rise time of the input pulse, said filter comprising, input means for receiving said input pulse; differentiator means operatively coupled with said input means for differentiating said input pulse; proportioning means operatively coupled with said input means for obtaining a signal which is a constant fraction of said input pulse; differencing means operatively coupled with said differentiator means and said proportioning means for obtaining an output pulse, said output pulse comprising the difference between the differentiated input pulse and the signal which is a constant fraction of the input pulse; and output means for receiving the output pulse.

Claim 13

An amplitude-compensated, rise time-compensated filter for receiving an input pulse having a substantially linear leading edge and non-zero rise time and for converting said input pulse to a bipolar output pulse having a zero-crossing time that is independent of the amplitude and rise time of the input pulse, said filter comprising, input means for receiving said input pulse; differentiator means operatively coupled with said input means for differentiating said input pulse; proportioning means operatively coupled with said input means for obtaining a signal which is a constant fraction of said input pulse; differencing means operatively coupled with said differentiator means and said proportioning means for obtaining an output pulse, said output pulse comprising the difference between the differentiated input pulse and the signal which is a constant fraction of the input pulse; and output means for receiving the output pulse.

Claim 14

The filter of claim 11, wherein said differentiating means differentiates the linear leading edge of the input pulse.

Claim 15

The filter of claim 12, further comprising an isolation amplifier coupled between said input means and said differentiator and proportioning means.

Claim 16

The filter of claim 12, wherein said output means is coupled with a level-crossing discriminator.

Claim 17

The filter of claim 12, further comprising a low-pass filter coupled between said differencing means and said output means.

Claim 18

The filter of claim 13, further comprising a low-pass filter coupled between said isolation amplifier and said differentiator and proportioning means.

Claim 19

An amplitude-compensated, rise-time-compensated filter for receiving an input pulse having a substantially linear portion during the leading edge and non-zero rise time and for converting said input pulse to a bipolar output pulse having a zero-crossing time that is independent of the amplitude and rise time of the input pulse, said filter comprising, input means for receiving said input pulse; balanced-amplifier means operatively coupled with said input means for providing a positive-polarity pulse proportional to the input pulse and a negative-polarity pulse proportional to the input pulse; differentiator means operatively coupled with said balanced-amplifier means for receiving and differentiating the positive-polarity pulse; proportioning means operatively coupled with said balanced-amplifier means for receiving said negative-polarity pulse and for obtaining a constant fraction thereof; summing means operatively coupled with said differentiator means and said proportioning means for obtaining said output pulse by summing the differentiated positive-polarity pulse with the fractional negative-polarity pulse; and output means for receiving the output pulse.

Claim 20

An amplitude-compensated, rise-time-compensated filter for receiving an input pulse having a substantially linear portion during the leading edge and non-zero rise time and for converting said input pulse to a bipolar output pulse having a zero-crossing time that is independent of the amplitude and rise time of the input pulse, said filter comprising, input means for receiving said input pulse; balanced-amplifier means operatively coupled with said input means for providing a positive-polarity pulse proportional to the input pulse and a negative-polarity pulse proportional to the input pulse; differentiator means operatively coupled with said balanced-amplifier means for receiving and differentiating the positive-polarity pulse; proportioning means operatively coupled with said balanced-amplifier means for receiving said negative-polarity pulse and for obtaining a constant fraction thereof; summing means operatively coupled with said differentiator means and said proportioning means for obtaining said output pulse by summing the differentiated positive-polarity pulse with the fractional negative-polarity pulse; and output means for receiving the output pulse.