Count Value Generation Circuit for Phase-Accurate Frequency Measurement

The patent divides the frequency measurement function into two separate modules: a direct count module that counts reference clock cycles during the input signal period, and a reciprocal count module that counts input signal cycles during the reference clock period. This segmentation allows each module to operate independently with its own timing mechanism, eliminating the clock skew problem that arises when multiple modulators share a common clock signal with phase differences.

The patent implements reciprocal counting by inverting the traditional counting approach. Instead of only counting reference clock cycles (direct count), it also counts input signal cycles (reciprocal count) and combines both results. This inversion strategy provides redundant measurement paths that compensate for each other's limitations and improve overall measurement accuracy without requiring synchronized multiple clock signals.

The patent creates a universal frequency measurement circuit that can measure both high and low frequencies by integrating direct count and reciprocal count functionalities into a single system. The same circuit structure handles both counting modes, making the system multi-functional without requiring separate dedicated circuits for different measurement scenarios. This universal approach simplifies the overall device architecture compared to using multiple specialized modulators.

The patent merges the direct count and reciprocal count functions into a unified frequency measurement system. Both counting operations share common components such as the period measurement unit and the final calculation logic, reducing the total component count and circuit complexity. This combination eliminates the need for multiple independent frequency delta sigma modulators while maintaining comprehensive measurement coverage.