Frequency measurement process involving integration - performs second integration which is effected through same integrator used for first integration

摘要

The circuit is used for frequency measurement with measurement of period of oscillation duration. It involves integration of an electrical value and the integrated result is used to give a signal derived from a second integration. The electrical value utilised in the first integration is directly employed, with the aid of the same integrator, in the second integration. The signal is compared with threshold values derived from the constants of the various frequency determinations and a predetermined voltage difference. From the comparison there is obtained a time signal which is proportional to the unknown frequency. A constant voltage can be fed as an input to a switch for an inverted integrator used in a frequency measurement circuit.