摘要 |
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.
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