DSD Audio Signal Switching with Pre-Interpolation Frequency Matching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for switching between DSD signals with different sampling frequencies, such as those described in PTL 1, require conversion to PCM signals and crossfading, which are burdensome for ordinary CPUs and result in signal processing delays, and cannot handle delta-sigma modulated signals directly.
Innovation Solution
A signal processing apparatus and method that includes an acquisition section to select a digital audio signal with a given sampling frequency and an interpolation section to perform a pre-interpolation process when the sampling frequency is lower than the operating clock of a delta-sigma demodulator, allowing for direct switching between DSD signals without conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conversion to PCM signal and crossfading is performed during switching, then switching between DSD signals can be achieved, but processing burden increases and delays occur
Solution Approach 1:
The patent extracts the delta-sigma modulated signal directly from the DSD signal without converting it to PCM format. By taking out only the necessary modulation information and processing it in the delta-sigma domain, the system avoids the complex PCM conversion and crossfading operations while maintaining switching capability between different sampling frequencies.
Solution Approach 2:
The patent introduces a delta-sigma modulator as an intermediary device that operates directly on the DSD signal. This intermediary processes the signal in the delta-sigma domain rather than converting to PCM, enabling smooth transitions between different sampling frequencies through modulation domain processing instead of time-domain crossfading.
2Adaptability or versatility
If PCM conversion and crossfading are used for switching, then DSD signal switching is possible, but ordinary embedded CPUs cannot handle the processing burden
Solution Approach 1:
The patent replaces the computationally intensive PCM conversion and crossfading operations with a hardware-based delta-sigma modulator. This substitution moves the processing from software/CPU execution to dedicated hardware circuitry, dramatically reducing the CPU burden and energy consumption while enabling DSD signal switching functionality.
Solution Approach 2:
The delta-sigma modulator performs the switching operation autonomously in the modulation domain without requiring CPU intervention for complex calculations. The system serves itself by handling the switching through dedicated hardware that naturally processes DSD signals, eliminating the need for energy-intensive CPU-based PCM conversion and crossfading algorithms.
3Ease of operation
If crossfading is performed during switching, then DSD signal transitions can be achieved, but signal processing delays occur
Solution Approach 1:
The patent performs preliminary delta-sigma modulation on the incoming DSD signal before switching occurs. By pre-modulating the signal and maintaining it in the delta-sigma domain, the system eliminates the need for time-consuming PCM conversion and crossfading operations during the actual switching moment, thereby reducing processing delays.
Solution Approach 2:
The patent skips the intermediate PCM conversion step and the crossfading process entirely by operating directly in the delta-sigma modulation domain. This allows the system to rush through the switching operation using simple modulation domain adjustments, avoiding the time-consuming sequential processing of conversion and crossfading that characterizes conventional approaches.
Data Source
AI summary
The present technology relates to a signal processing apparatus, a signal processing method, and a program that permit switching between a plurality of DSD signals having different sampling frequencies using a simple configuration.An acquisition section acquires a digital audio signal having a given sampling frequency selected from among the plurality of digital audio signals acquired by delta-sigma modulating an audio signal at a plurality of sampling frequencies. An interpolation section subjects the acquired digital audio signal to a pre-interpolation process when the sampling frequency of the acquired digital audio signal is lower than an operating clock of a delta-sigma demodulator. The present technology is applicable, for example, to a signal processing apparatus.