Single-Chip Tone Detection Using Edge Reset and Counter Timing
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Solution Overview
Problem
Existing tone detection solutions, particularly in electronic devices, face challenges due to multi-chip configurations that increase cost and space, and filtering methods that are limited to specific frequency bands and require external components, making them unsuitable for low-frequency tone detection and power-efficient integration.
Innovation Solution
A digital tone detector comprising a comparator, edge detectors, a counter, and a flip-flop that generates square wave outputs and reset signals to detect tone presence and duration, allowing for a single integrated circuit solution in CMOS process, avoiding the need for large capacitors and external filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-chip solutions with diodes, amplifiers and capacitors are used for tone detection, then tone detection capability is achieved, but cost and device space increase
Solution Approach 1:
The patent combines multiple tone detection functions into a single integrated circuit chip, merging what were previously separate diodes, amplifiers, capacitors, and detection circuits into one unified device. This integration eliminates the need for multi-chip configurations while maintaining full tone detection capability across multiple frequency ranges.
Solution Approach 2:
The integrated circuit is designed to perform multiple tone detection functions simultaneously across different frequency bands (including low frequency 10-25 KHz, mid frequency, and high frequency ranges) using a single chip architecture, making the device universal rather than specialized for one frequency range.
2Measurement precision
If large capacitors are used for low frequency tone detection (10-25 KHz), then detection accuracy is improved, but device space and cost increase
Solution Approach 1:
The patent implements small on-chip capacitors that are nested within the integrated circuit structure, replacing the need for large off-chip capacitors. The nested capacitor design allows sufficient capacitance value for low frequency detection while occupying minimal space within the chip architecture.
Solution Approach 2:
The patent changes the physical parameters of the capacitors by transitioning from large off-chip discrete capacitors to small on-chip integrated capacitors with optimized capacitance values that are sufficient for low frequency tone detection while dramatically reducing the required physical space.
3Measurement precision
If filter based detection methods are used, then specific frequency signals can be isolated, but external components are required and application versatility is limited
Solution Approach 1:
The patent employs dynamic frequency detection capability where the integrated circuit can adaptively detect and respond to tones across multiple frequency bands without requiring external filter components. The circuit dynamically adjusts its detection parameters to identify tones in low frequency (10-25 KHz), mid frequency, and high frequency ranges using its internal architecture.
Solution Approach 2:
The patent extracts and eliminates the requirement for external filter components by integrating all necessary frequency selection and detection functionality directly into the chip. The detection circuit uses its internal structure to isolate and detect specific frequency signals without needing external passive components.
4Measurement precision
If digital filtering techniques and Fourier transforms are used for tone detection, then accurate tone detection is achieved, but power consumption and die space increase
Solution Approach 1:
The patent employs a simplified detection architecture that uses basic analog circuitry (comparators, edge detectors, counters, and flip-flops) instead of computationally intensive digital signal processing methods. This approach trades some computational complexity for lower power consumption and smaller die area, achieving sufficient detection accuracy for practical applications.
Solution Approach 2:
The patent replaces complex digital signal processing mechanisms (Fourier transforms and digital filtering) with simpler analog detection mechanisms using comparators and edge detectors, thereby reducing the computational burden, power consumption, and hardware resources required for accurate tone detection.
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
This solution enables efficient detection of tones across various frequencies, including low-frequency ranges, with reduced component count and power consumption, facilitating integration in communication devices and other applications without the limitations of prior art.
Implementation Method 1
a comparator configured to connect to an input. The input intermittently receives a tone signal and the comparator generates a square wave output signal in response to a tone signal
Implementation Method 2
one or more edge detectors configured to detect an edge of the square wave signal and responsive to detection of an edge, generate a reset signal
Implementation Method 3
A counter is present and configured to generate a maximum value signal unless reset by receipt of the reset signal prior to reaching a maximum counter value
Data Source
AI summary
A tone detector is disclosed that is realizable in digital embodiment on a single integrated circuit die and does not require external components, such as a discrete capacitor. An input connects to a comparator, which in turn connects to one or more edge detectors and a flip flop. The edge detector outputs a pulse responsive to a detected edge. A counter is reset by the pulses from the edge detectors thereby preventing the counter from reaching a maximum value, which would otherwise be output from the counter and provided to a flip flop to clock in the comparator output at the D input to the flip flop. In operation, the comparator generates a rail to rail signal responsive to a received tone, which in turn is clocked through the flip flop as a logic high output indicating presence of a tone.