BLE Transmit Modulation Testing Using VCO Slice Linearity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Bluetooth Low Energy (BLE) transmit modulation tests are costly, time-consuming, and require expensive equipment, leading to shipment delays due to the need for traditional testing methods.
Innovation Solution
A low-cost, fast, and accurate test technique implemented in firmware that evaluates individual slices of an analog varactor array within a voltage-controlled oscillator (VCO) to detect non-linearities, using resistor ladder voltages and control voltages to measure frequency variations and determine VCO gain linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional BLE transmit modulation tests are performed using conventional production test equipment, then measurement precision and reliability are improved, but test time and cost increase significantly
Solution Approach 1:
The patent segments the VCO tuning range into multiple slices, each controlled by a separate control voltage range. By testing each slice independently and identifying non-linearities in frequency vs. control voltage relationship, the system detects modulation failures without requiring traditional expensive modulation test equipment. This segmentation approach maintains measurement precision while enabling faster, simpler testing.
Solution Approach 2:
The patent creates a simplified test model that copies only the essential functionality needed for modulation failure detection. Instead of implementing full BLE modulation testing, it measures frequency vs. control voltage characteristics of the VCO, which are sufficient to detect non-linearities that cause modulation failures. This copying approach reduces test complexity and time while maintaining detection accuracy.
2Measurement precision
If traditional BLE transmit modulation tests are performed with expensive test equipment, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the essential testing function from complex modulation test equipment. By isolating the VCO frequency vs. control voltage measurement capability, it removes the need for expensive modulation signal generators, spectrum analyzers, and other complex test equipment. The extracted measurement approach uses only basic frequency measurement functions available in standard microcontrollers.
Solution Approach 2:
The patent replaces expensive, complex test equipment with inexpensive, readily available microcontroller units that can perform frequency measurements. The test implementation uses standard digital-to-analog converters and frequency counters already present in most modern microcontrollers, eliminating the need for dedicated expensive test equipment while maintaining sufficient measurement precision.
3Manufacturing precision
If comprehensive VCO slice testing is performed with multiple reference voltage values and control voltage values, then manufacturing precision is improved, but test time increases
Solution Approach 1:
The patent performs preliminary characterization of the VCO by measuring frequency vs. control voltage across multiple slices and reference voltage values during manufacturing. This preliminary data collection enables the establishment of baseline linearity characteristics, which can then be used for faster production testing. The comprehensive initial measurement ensures manufacturing precision while the data can be reused for subsequent quick verification tests.
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 test approach quickly and accurately detects BLE transmit modulation failures by isolating defects in VCO slices, reducing test time and cost by eliminating the need for conventional production test equipment and ensuring compliance with BLE modulation specifications.
Implementation Method 1
a voltage-controlled oscillator (VCO) including an LC tank and an analog varactor array coupled to the LC tank, the analog varactor array including a plurality of slices
Data Source
AI summary
Modulation testing separately enables slices of an analog varactor array of an LC oscillator. For each enabled slice, a reference voltage supplying a resistor ladder is set to a plurality of different reference voltage values. Resistor ladder voltages generated for the different reference voltage values are supplied to the enabled slice and a control voltage coupled to the enabled slice is swept for each of the reference voltage values. Respective frequencies of an oscillator signal coupled to an output of the LC oscillator are measured for each enabled slice for each combination of the reference voltage values and the control voltage values. The linearity of LC oscillator gain is determined for each of the reference voltage values for each slice based on the respective frequencies and the control voltage values. Passing/failing the modulation testing is based on the linearity of the LC oscillator gain.