Unsaturable sense amplifier for pacer system analyzer
First Claim
1. An unsaturable sense amplifier for use in a pacer system analyzer to sense and amplify intracardiac signals induced in response to pacing pulses being applied to the heart of a patient, comprising:
- first amplifier means for amplifying an applied voltage and being subject to saturation by said applied voltage exceeding a first predetermined saturating level;
second amplifier means coupled to the output of said first amplifier means for amplifying said output of said first amplifier means and being subject to saturation by said output exceeding a second predetermined saturating level;
input limiting means coupled to the input of said first amplifier means for limiting said applied voltage to less than said first predetermined saturating level;
output limiting means connected between the input and output of said second amplifier means for limiting said input of said second amplifier means to less than said second predetermined saturating level; and
artifact squelch means coupled to said output of said second amplifier means for squelching said output when said output exceeds a predetermined squelch level.
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Abstract
An unsaturable cardiac sense amplifier includes first and second amplifying stages, each of which is subject to saturation by excessive input voltage. Input voltage to the first amplifier stage is limited to less than a saturating level by means of a pair of parallel, oppositely sensed, diodes. Saturation of the second amplifier stage is prevented by a degenerative feedback loop formed by a pair of serially connected zener diodes. An artifact squelch circuit, connected to the output of the second amplifier stage, limits the maximum output voltage of the sense amplifier.
46 Citations
10 Claims
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1. An unsaturable sense amplifier for use in a pacer system analyzer to sense and amplify intracardiac signals induced in response to pacing pulses being applied to the heart of a patient, comprising:
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first amplifier means for amplifying an applied voltage and being subject to saturation by said applied voltage exceeding a first predetermined saturating level; second amplifier means coupled to the output of said first amplifier means for amplifying said output of said first amplifier means and being subject to saturation by said output exceeding a second predetermined saturating level; input limiting means coupled to the input of said first amplifier means for limiting said applied voltage to less than said first predetermined saturating level; output limiting means connected between the input and output of said second amplifier means for limiting said input of said second amplifier means to less than said second predetermined saturating level; and artifact squelch means coupled to said output of said second amplifier means for squelching said output when said output exceeds a predetermined squelch level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An unsaturable sense amplifier for use in a pacer system analyzer to sense and amplify intracardiac signals induced in response to pacing pulses being applied to the heart of a patient, comprising:
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first amplifier means comprising a differential amplifier having a pair of input terminals and responsive to the differential voltage between said input terminals for amplifying an applied voltage, said amplifier being subject to saturation by said applied voltage exceeding a first predetermined saturating level; second amplifier means coupled to the output of said first amplifier means for amplifying said output of said first amplifier means, said second amplifier means being subject to saturation by said output exceeding a second predetermined saturating level; input limiting means coupled to said input terminals of said differential amplifier and exhibiting a relatively high impedance when said applied voltage is less than said first saturating level, and a relatively low impedance when said applied voltage exceeds said first saturating level, for limiting said applied voltage to less than said first predetermined saturating level; output limiting means connected between the input and output of said second amplifier means, and exhibiting relatively high impedance when the output of said first amplifier means is less than said saturating level, and relatively low impedance when said output exceeds said second saturating level, for limiting said input of said second amplifier means to less than said second predetermined saturating level; and artifact squelch means coupled to said output of said second amplifier means for squelching said output when said output exceeds a predetermined squelch level. - View Dependent Claims (10)
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Specification