Composite Signal Processing for Extended Dynamic Range
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Solution Overview
Problem
Existing signal processing techniques for enhancing dynamic range, such as signal compression and time-varying gain controls, are incompatible with algorithms like noise reduction and echo cancellation, and are limited by standard digital channel characteristics in mobile phone applications.
Innovation Solution
A method that bundles the original input signal with an attenuated version for transmission over the same channel, using a capacitive network to create a composite output signal, allowing for a higher dynamic range at the expense of signal bandwidth, and involves conversion to digital signals using sigma-delta converters and modulation to separate the signals for processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If signal compression or time-varying gain control is used to enhance dynamic range, then the dynamic range is improved, but the linearity of the signal deteriorates and compatibility with noise reduction and echo cancellation algorithms is lost
Solution Approach 1:
The input signal is divided into two separate paths: one path processes the original signal and the other path processes an attenuated version of the signal. Each path maintains signal linearity independently, allowing both low-level and high-level signals to be processed without distortion. The segmented processing preserves compatibility with noise reduction and echo cancellation algorithms while achieving extended dynamic range through parallel signal paths.
2Reliability
If the original input signal is transmitted over a digital channel, then the signal quality is maintained, but the dynamic range is limited by the digital channel specifications
Solution Approach 1:
The patent merges the original input signal with an attenuated version of the same signal into a composite output signal. The attenuated signal path handles high-level inputs that would otherwise exceed the dynamic range of the digital channel, while the original signal path handles low-level inputs. This merging of parallel signal paths enables the system to transmit signals with extended dynamic range over the same digital channel without compromising signal quality or exceeding channel specifications.
3Stability of the object's composition
If an attenuated version of the signal is created and bundled with the original signal, then the dynamic range is enhanced, but the signal bandwidth increases
Solution Approach 1:
The system dynamically selects which signal path to use based on the input signal level. A switching mechanism or adaptive routing directs low-level signals through the original signal path and high-level signals through the attenuated signal path. This dynamic operation allows the system to achieve extended dynamic range while maintaining efficient bandwidth utilization, as only one signal path is actively transmitting at any given moment rather than both paths occupying full bandwidth simultaneously.
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 approach provides a linear signal with enhanced dynamic range, compatible with noise reduction and echo cancellation algorithms, while reducing bandwidth and power consumption, and is specifically designed for mobile phone applications.
Implementation Method 1
the capacitive network will comprise a series coupling capacitor for coupling the input signal to signal processing circuitry, and a capacitive voltage divider comprising two capacitors in series between an input node for receiving the input signal and ground
Data Source
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AI summary
A signal processing method for enhancing the dynamic range of a signal is disclosed. The method comprises: a) forming an attenuated signal from an input signal; b) filtering each of the input and the attenuated signals such that the sum of their bandwidths is less than or equal to the bandwidth of a transmission channel; c) modulating a first one of the filtered input signal and the filtered attenuated signal, whereby the filtered input signal and the filtered attenuated signal occupy respective non-overlapping frequency ranges within the bandwidth of the transmission channel; and d) combining the modulated signal with the second one of the filtered input signal and the filtered attenuated signal to form a composite output signal.