| 摘要 |
A digital cardiac pacer has an asynchronous interval counter to count clock pulses to establish a stimulation interval at the end of which it produces a pulse for initiating a stimulation pulse. A control counter to which amplified naturally occurring heat pulses or stimulation pulses are applied controls the delivery of a resetting pulse to the asynchronous interval counter to reinitiate its count. If the stimulation, heart, or an interference pulse is detected during the count of a "refractory period," the control counter is reset and the refractory period is extended. If another stimulation, heart, or interference, pulse is detected during the extended refractory period, no resetting pulse is delivered, and the asynchronous interval counter continues its normal count. If during the period of time following the extended refractory period a stimulation, heart, or interference pulse is received, the control counter produces a resetting pulse to reset the asynchronous interval counter. A delay circuit between the control and asynchronous counters causes the stimulation interval to be shortened during the reception of interference pulses. |
