Echo Preventing Circuit Using Shared AD and DA Converters
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Solution Overview
Problem
Existing echo preventing circuits in communicating devices, such as mobile phones, face challenges in achieving high precision echo cancellation while increasing costs and power consumption due to the need for multiple analog-to-digital (AD) and digital-to-analog (DA) converters.
Innovation Solution
A digital signal processing circuit that includes a filter setting mechanism using FIR filters to cancel echoes by subtracting specific analog signals, reducing the need for multiple converters and optimizing circuit components for reduced power consumption and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple AD converters and DA converters are used to achieve high precision echo cancellation, then echo cancellation precision is improved, but cost and power consumption increase
Solution Approach 1:
The patent merges the functions of multiple AD converters and DA converters into a single shared AD converter and single shared DA converter. The echo preventing circuit uses one AD converter to convert both the original sound signal and the echo signal, and one DA converter to convert both the processed sound signal and the canceling signal. This consolidation maintains high precision echo cancellation while reducing the number of converters from four (2 AD + 2 DA) to two (1 AD + 1 DA), thereby reducing power consumption and cost.
Solution Approach 2:
The single AD converter and single DA converter are designed to perform multiple functions: converting both the original sound signal and the echo signal, and converting both the processed sound signal and the canceling signal respectively. This multi-functionality allows the circuit to maintain high precision echo cancellation capabilities while using fewer components, thus reducing overall power consumption and cost.
2Measurement precision
If multiple AD converters and DA converters are used to achieve high precision echo cancellation, then echo cancellation precision is improved, but cost increases
Solution Approach 1:
The patent merges the functions of multiple AD converters and DA converters into a single shared AD converter and single shared DA converter. The echo preventing circuit uses one AD converter to convert both the original sound signal and the echo signal, and one DA converter to convert both the processed sound signal and the canceling signal. This consolidation maintains high precision echo cancellation while reducing the number of converters from four (2 AD + 2 DA) to two (1 AD + 1 DA), thereby reducing power consumption and cost.
Solution Approach 2:
The single AD converter and single DA converter are designed to perform multiple functions: converting both the original sound signal and the echo signal, and converting both the processed sound signal and the canceling signal respectively. This multi-functionality allows the circuit to maintain high precision echo cancellation capabilities while using fewer components, thus reducing overall power consumption and cost.
3Use of energy by moving object
If a simple circuit configuration is used for echo prevention, then cost and power consumption are reduced, but echo cancellation precision deteriorates
Solution Approach 1:
The echo preventing circuit uses feedback mechanisms where the AD converter converts the echo signal back to digital form, allowing the DSP to analyze and process the echo characteristics. The processed canceling signal is then converted back to analog by the DA converter and combined with the original sound signal. This feedback loop enables precise echo cancellation despite using fewer converters, maintaining high precision while reducing power consumption and cost.
Solution Approach 2:
The patent replaces the need for multiple physical converters with a digital signal processing approach. The DSP performs complex echo cancellation algorithms on digitally converted signals, then the single DA converter converts the processed signals back to analog. This substitution of mechanical/conversion-heavy approach with digital processing maintains precision while reducing hardware complexity and power consumption.
4Ease of manufacture
If a simple circuit configuration is used for echo prevention, then cost is reduced, but echo cancellation precision deteriorates
Solution Approach 1:
The patent merges the functions of multiple AD converters and DA converters into a single shared AD converter and single shared DA converter. The echo preventing circuit uses one AD converter to convert both the original sound signal and the echo signal, and one DA converter to convert both the processed sound signal and the canceling signal. This consolidation maintains high precision echo cancellation while reducing the number of converters from four (2 AD + 2 DA) to two (1 AD + 1 DA), thereby reducing power consumption and cost.
Solution Approach 2:
The patent replaces the need for multiple physical converters with a digital signal processing approach. The DSP performs complex echo cancellation algorithms on digitally converted signals, then the single DA converter converts the processed signals back to analog. This substitution of mechanical/conversion-heavy approach with digital processing maintains precision while reducing hardware complexity and power consumption.
Data Source
AI summary
An echo preventing circuit comprises a filter that is inputted with a first digital signal and outputs a second and a third digital signals; a first DA converter that converts the second digital signal into a first analog signal and outputs the first analog signal; a second DA converter that converts the third digital signal into a second analog signal and outputs the second analog signal; an input/output terminal that outputs the first analog signal or that is inputted with a third analog signal; a subtracting circuit that outputs a fourth analog signal obtained by subtracting the second analog signal from a signal formed by combining the first analog signal and the third analog signal; and an AD converter that converts the fourth analog signal into a fourth digital signal and outputs the fourth digital signal, wherein the filter sets filter coefficients for which the fourth analog signal is a signal formed by removing or attenuating the first analog signal from a signal formed by combining the first analog signal and the third analog signal, based on the fourth digital signal outputted from the AD converter when signals are inputted into the first and the second DA converters while the third analog signal is not present, and wherein the fourth analog signal outputted from the subtracting circuit is outputted as an output signal corresponding to the third analog signal.