Multi-channel Decoding Circuit Clock Amplitude Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multi-channel decoding systems experience noise issues, such as 'pop' noise, when switching between multi-channel and single-channel modes due to differences in output DC voltage levels and glitch phenomena, primarily caused by an equivalent offset voltage source.
Innovation Solution
A multi-channel decoding system that includes a decoding circuit and a clock generating circuit, which gradually changes the amplitude of the clock signal when switching modes, and a calibration circuit that adjusts the DC voltage level of channel output signals to match a predetermined reference signal level, reducing the noise by ensuring consistent voltage levels in both modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the stereo decoding system switches between stereo and mono modes, then the channel configuration is changed to meet different listening needs, but pop noise is introduced due to DC voltage level changes
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the DC voltage levels in both stereo and mono modes to be equal before mode switching occurs. The equalizing circuit proactively sets the DC voltage of the mono channel to match the DC voltage of the stereo channels, so that when switching happens, there is no voltage level difference to cause pop noise. This preventive measure eliminates the harmful effect before it can occur.
Solution Approach 2:
The patent changes the DC voltage level parameter of the channel output signals to resolve the contradiction. By using an equalizing circuit that adjusts and equalizes the DC voltage levels across different channel modes, the system maintains consistent DC voltage parameters regardless of whether it is in stereo or mono mode, thereby preventing pop noise during mode transitions.
2Speed
If the clock signal amplitude changes abruptly during mode switching, then the channel configuration transitions quickly, but glitch phenomenon occurs causing noise
Solution Approach 1:
The patent applies dynamics by making the clock signal amplitude change gradually rather than abruptly during mode switching. The clock generating circuit dynamically adjusts the amplitude of the clock signal over time, creating a smooth transition that avoids sudden changes. This dynamic amplitude modulation prevents the glitch phenomenon while still achieving mode switching, resolving the contradiction between switching speed and noise generation.
Data Source
AI summary
A multi-channel decoding method includes: receiving an input signal to generate a first channel output signal and a second channel output signal, wherein the input signal is mixed with a specific clock signal; and gradually changing an amplitude of the specific clock signal from a first value to a second value when switching from a first mode corresponding to a first number of channels to a second mode corresponding to a second number of channels. Systems utilizing the method and another method further comprising calibration are also disclosed.