Gain Update Circuit Timing for Synchronized Audio Gain Stages
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Solution Overview
Problem
Existing gain control systems face challenges in synchronizing low- and high-resolution gain updates in signal chains, leading to signal transients and audible artefacts, particularly in digital audio processing systems where analog and digital gain stages require separate control units.
Innovation Solution
An integrated circuit (IC) with gain update circuitry that compensates for signal chain delays by delaying internal gain control signals relative to external control signals, using zero-crossing detection to time-align gain updates and incorporating a synchronization module to synchronize multiple gain stages, thereby eliminating the need for separate timing controllers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate control units are used for analog and digital gain stages, then each gain stage can be controlled independently, but synchronization of gain updates becomes difficult leading to signal transients and audible artefacts
Solution Approach 1:
The patent combines separate control units into a single integrated control unit that manages both analog and digital gain stages. This control unit uses zero-crossing detection to synchronize gain updates across both stages, preventing signal transients and audible artifacts while maintaining independent control capability through unified timing management.
Solution Approach 2:
The control unit implements feedback through zero-crossing detection circuitry that monitors the input signal and uses the detected zero-crossing events as timing references. This feedback mechanism ensures that gain updates occur at optimal moments in the signal cycle, maintaining synchronization between analog and digital stages.
2Speed
If gain control signals are updated immediately, then the system responds quickly to control changes, but signal chain delays cause misalignment between control signals and actual gain application
Solution Approach 1:
The control unit performs preliminary actions by detecting zero-crossing events in advance and using these events as triggers for gain updates. This preliminary detection allows the system to prepare for gain changes at the optimal moment, ensuring both quick response and precise alignment with the signal chain timing.
3Measurement precision
If analog potentiometer is used for continuous gain variation, then fine-resolution gain control is achieved, but digital control integration becomes difficult
Solution Approach 1:
The patent replaces the mechanical analog potentiometer system with a digital control system that uses zero-crossing detection and digital timing mechanisms. This substitution maintains fine-resolution gain control capability while enabling full digital control integration, allowing the system to be controlled by digital means and easily integrated into digital audio processing systems.
Data Source
AI summary
An integrated circuit (IC), comprising: a first input pin for receiving a first input signal; a first converter configured to convert the first input signal to a first output signal; a first gain stage configured to apply a first gain to the first output signal; gain update circuitry configured to: output a first external gain control signal to a first output pin of the IC; and subsequently output a first internal gain control signal to the first gain stage to update the first gain of the first gain stage, wherein output of the first internal gain control signal is delayed relative to output of the first external gain control signal by a first predetermined delay, the first predetermined delay to compensate for signal chain delay between the first input pin and the first gain stage.