Frequency Measurement Device Using Short Gate Time Count Method
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Solution Overview
Problem
Existing frequency measurement systems face challenges in detecting small changes in frequency with high resolving power, particularly in odor sensors, due to low frequency resolving power and errors associated with direct count systems, and the need for large-scale circuits in reciprocal systems, especially when dealing with multiple sensors.
Innovation Solution
A frequency measuring device using a 'short gate time count method' that multiplies the signal to be measured, counts it with a short gate time, and applies a low-pass filter to remove high frequency components, thereby enhancing dynamic range and reducing noise, utilizing a phase locked loop circuit for noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct count system is used for frequency measurement, then circuit scale is small, but frequency resolving power is low and gate time must be long
Solution Approach 1:
The invention divides the frequency measurement task into multiple channels, each with its own counter operating in parallel. This segmentation allows each counter to use short gate time while the system as a whole achieves high frequency resolving power through statistical processing of multiple independent measurements.
Solution Approach 2:
The invention uses periodic gating signals to enable continuous measurement cycles. By repeatedly measuring frequency over short periodic intervals and accumulating statistical data, the system achieves high frequency resolving power without requiring long continuous gate times.
2Measurement precision
If reciprocal system is used for frequency measurement, then frequency resolving power is high, but circuit scale is large
Solution Approach 1:
Instead of using a single complex reciprocal counter, the invention segments the measurement function across multiple simple direct counters. Each counter independently measures frequency with short gate time, and the system achieves high resolving power through statistical processing of multiple measurements.
Solution Approach 2:
The invention creates multiple copies of simple counter circuits operating in parallel. Each counter is a simplified version that can be easily replicated, and collectively they provide the measurement precision that would require a much more complex single counter.
3Adaptability or versatility
If multiple odor sensors are deployed, then detection capability is improved, but circuit scale increases significantly
Solution Approach 1:
The invention divides the sensor array into multiple independent measurement channels, each with its own counter. This modular segmentation allows each channel to be a simple, standardized unit that can be replicated without proportionally increasing overall system complexity.
Solution Approach 2:
The invention creates universal counter modules that can serve multiple sensors. Each counter is designed as a standardized, multi-functional unit that can be assigned to different sensors based on measurement needs, reducing the need for dedicated complex circuitry for each sensor.
4Measurement precision
If gate time is extended to improve frequency resolving power, then measurement precision improves, but errors from oscillator stability are superposed
Solution Approach 1:
The invention uses short periodic measurement cycles instead of long continuous measurements. By repeatedly performing measurements over short intervals and processing the results statistically, the system achieves high frequency resolving power while minimizing the impact of oscillator drift and stability errors.
Solution Approach 2:
The invention implements statistical processing of multiple measurements that effectively filters out errors from oscillator instability. By analyzing the distribution and variation of multiple short-term measurements, the system can distinguish between random counting errors and systematic oscillator drift, improving overall measurement accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves improved frequency measurement resolving power with reduced noise and a smaller circuit scale, enabling detection of small frequency changes and facilitating multichannel implementation, particularly suitable for odor sensors and other applications.
Implementation Method 1
a phase locked loop circuit for noise reduction
Implementation Method 2
a low-pass filter that outputs a signal corresponding to the frequency of the signal to be measured based on the count value outputted at the predetermined period
Implementation Method 3
a QCM (Quarts Crystal Microbalance) method that uses a quartz oscillator may be used to convert a very small change in mass at a substrate surface of the oscillator to a frequency change
Data Source
AI summary
A frequency measurement device for measuring a frequency of a signal to be measured including a pulse signal, includes: a signal multiplier section that multiplies the signal to be measured by n (n is an integer) and outputs a multiplied signal; a counter section that counts the multiplied signal with a predetermined gate time and outputs a count value of the frequency of the signal to be measured at a predetermined period; and a low-pass filter that outputs a signal corresponding to the frequency of the signal to be measured based on the count value outputted at the predetermined period.