Extremely wide range frequency measurement method

摘要

This invention discloses a digital frequency measurement system, providing high accuracy and a fast dynamic response over an extremely wide frequency range. This measurement system provides for double buffering of pulse count and pulse period, so that data information change during transfer of this information to the software interrupt routine cannot happen. At each rising and/or falling edge of the measured signal a content of the interval timer is stored into the timer storage device and a content of the pulse counter is changed (incremented or decremented). Each time an interrupt request is generated, a content of the timer storage device is stored into the additional storage device, and a content of the pulse counter is stored into the counter storage device. On the basis of the difference between contents of the additional storage device in the current and the previous interrupt routine, and on the basis of the difference between contents of the counter storag device in the current and the previous interrupt routine, a measured frequency is calculated.