Frequency Determination Using Dual Phase Counting
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Solution Overview
Problem
Conventional frequency measurement methods are unreliable and delayed, especially at low input frequencies, requiring a complete period of the input signal for determination, which leads to significant delays and potential inability to determine frequency when it drops to near 0 Hz.
Innovation Solution
The method involves counting clock edges during separate level phases of an input signal to determine frequency, allowing for continuous updates without waiting for a full period, using first and second count values to calculate the frequency based on a reference clock signal, and incorporating a comparison value for early approximation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional frequency measurement waits for a complete period of the input signal, then measurement reliability is improved, but step response time increases significantly at low frequencies
Solution Approach 1:
The patent divides the measurement process into two separate counting operations: one for the first level phase and one for the second level phase of the input signal. This segmentation allows frequency determination to be based on the sum of both count values rather than waiting for a complete period, thereby reducing step response time while maintaining measurement reliability through the combined measurement data from both phases.
2Adaptability or versatility
If the input frequency drops to near 0 Hz, then low frequency measurement capability is improved, but the system cannot determine frequency reliably
Solution Approach 1:
The patent enables continuous frequency determination by performing counting operations during both the first and second level phases of the input signal. This continuous measurement approach ensures that frequency can be determined reliably even at very low frequencies or near 0 Hz, as the system continuously accumulates count values from both phases rather than waiting for complete signal periods.
3Productivity
If frequency determination is updated with each level change, then productivity is improved, but measurement precision may be compromised without sufficient measurement periods
Solution Approach 1:
The patent uses the sum of count values from both the first and second level phases to determine frequency, which provides sufficient measurement data for accurate frequency determination. This partial measurement approach (using both phases rather than waiting for multiple complete periods) achieves the desired measurement precision while enabling faster frequency updates with each level change.
Data Source
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AI summary
In a method for determining a frequency of an input signal (IN) a first count (N1) is determined by counting clock pulse edges of a reference clock signal (CLK), whilst the input signal (IN) corresponds to a first level value (L1). Furthermore a second count (N2) is determined by counting clock pulse edges of the reference clock signal (CLK), whilst the input signal (IN) corresponds to a second level value (L2). The frequency of the input signal (IN) is determined on the basis of the first and the second counts (N1, N2).