VOX Sensitivity Adjustment for Hands-Free Radio Communication
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Solution Overview
Problem
In radio communication devices with a Voice-operated Transmit (VOX) function, users must consciously speak at a high volume to activate the VOX function, making hands-free calls unnatural and sensitive to ambient sound levels.
Innovation Solution
A radio communication device with a transmitter, receiver, voice level comparator, and VOX sensitivity level calculator that adjusts the VOX sensitivity based on ambient sound levels, allowing for automatic activation of the VOX function without requiring users to be aware of their voice levels, using a dual sensitivity level system to optimize operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the VOX function uses a fixed sensitivity level threshold, then the device can activate transmission when voice reaches that level, but users must consciously speak at high volume to activate it, making hands-free calls unnatural
Solution Approach 1:
The system performs preliminary action by calculating and storing the VOX sensitivity level during the reception period before transmission is needed. The processor calculates the VOX sensitivity level based on ambient sound collected during reception, and stores this calculated level for subsequent transmission determination, eliminating the need for users to consciously adjust their voice volume.
Solution Approach 2:
The system implements dynamics by making the VOX sensitivity level variable rather than fixed. The sensitivity level is dynamically adjusted based on ambient sound conditions - it changes according to the reception period's ambient sound levels, allowing the system to adapt to different environments (quiet rooms, noisy streets, vehicles) without user intervention.
2Measurement precision
If the VOX sensitivity level is set low to detect soft voices, then natural speaking is detected, but ambient noise causes false activations
Solution Approach 1:
The system performs preliminary measurement of ambient sound levels during the reception period before transmission is required. By calculating the VOX sensitivity level based on ambient sound collected during reception, the system establishes a baseline that accounts for current environmental noise conditions, preventing false activations while maintaining sensitivity to natural voice levels.
Solution Approach 2:
The system implements feedback by continuously monitoring ambient sound levels and using this information to adjust the VOX sensitivity threshold. The processor calculates the sensitivity level based on received ambient sound and uses this calculated level to determine whether to activate transmission, creating a closed-loop system that adapts to changing environmental conditions.
3Reliability
If the VOX sensitivity level is set high to avoid false activation from ambient noise, then false activations are prevented, but users must speak at high volume to activate transmission
Solution Approach 1:
The system makes the VOX sensitivity level dynamic rather than fixed. By adjusting the sensitivity level according to ambient sound conditions measured during reception, the system maintains high reliability in noisy environments (higher threshold) while enabling natural voice activation in quiet environments (lower threshold), eliminating the need for users to consciously speak at high volume.
Solution Approach 2:
The system changes the sensitivity parameter based on environmental conditions. The processor calculates a appropriate sensitivity level by referencing ambient sound levels during reception, and uses this calculated parameter to determine transmission activation, adapting the system's behavior to match the acoustic environment.
4Adaptability or versatility
If the system calculates VOX sensitivity level continuously, then accurate adaptation to ambient sound is achieved, but processing load and power consumption increase
Solution Approach 1:
The system implements periodic action by calculating the VOX sensitivity level only during specific periods - the reception period - rather than continuously. The processor calculates the sensitivity level based on ambient sound collected during reception, then stores this calculated level for use during subsequent transmission periods, reducing processing load while maintaining adaptability.
Solution Approach 2:
The system performs preliminary calculation of the VOX sensitivity level during the reception period before transmission is needed. By pre-calculating and storing the sensitivity level during reception, the system avoids continuous processing during transmission, reducing power consumption while maintaining accurate ambient sound adaptation.
Data Source
AI summary
A transmitter modulates an input voice signal to transmit an RF signal. A receiver demodulates a received RF signal to output an output voice signal. A voice level comparator compares a level of an input voice signal obtained by collecting a voice by a microphone with a VOX sensitivity level. A transmission determination unit instructs the transmitter to transmit the input voice signal, when the level of the input voice signal is equal to or greater than the VOX sensitivity level, based on a comparison result by the voice level comparator. A VOX sensitivity level calculator calculates the VOX sensitivity level in a predetermined period until just before the receiver completes outputting the output voice signal, based on an ambient sound collected by the microphone.