| 摘要 |
This application relates to means for measuring and recording the frequency of repetitive events which may be subject to large changes in frequency, and is particularly useful in connection with the measuring and recording of heartbeats. This is accomplished by generating a train of pulses responsive to events of interest, establishing a dc potential responsive to the frequency of said train of pulses, generating a linear sawtooth pulse whose amplitude is responsive to the frequency of the applied pulses and to said dc potential, comparing said amplitude of said sawtooth pulses with a reference voltage, and modifying said dc potential responsive to the difference between said reference voltage and said sawtooth pulse amplitude, and providing means responsive to the magnitude of said dc potential to indicate the frequency of the pulses of interest.
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