S/PDIF Bitstream Generator Noise Filtering
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Solution Overview
Problem
Conventional apparatuses for regenerating S/PDIF data often fail to accurately decode audio signals due to noise-induced errors, as the audio clock is not directly transmitted and can become misaligned, leading to distortion or failure in playing the data.
Innovation Solution
An apparatus and method that utilize a decision unit with a comparator, temporary storage, multiplexer, and delay circuit to compare current and previous control words, selectively outputting the previous control word if noise is detected, ensuring accurate generation of a bitstream by discarding noisy blocks and maintaining a stable preamble.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the audio clock is obtained from related clock information as a ratio, then the system can operate with changing sampling rates, but noise is introduced causing bit errors and data distortion
Solution Approach 1:
A decision unit is introduced as an intermediary component between the clock recovery circuit and the data transmitter. This decision unit compares the currently recovered audio clock with previously stored clock information to detect noise and determine whether to use the current or previous clock data, thereby filtering out noisy bits while preserving adaptability
Solution Approach 2:
The system implements feedback by continuously monitoring the quality of recovered audio clock data and using this information to adjust the transmission process. The decision unit feeds back whether to use current or previous clock information based on noise detection, creating a closed-loop system that maintains data accuracy while adapting to changing sampling rates
2Duration of action of stationary object
If noise exists in the audio stream, then the system can maintain continuous operation, but bits are erroneously converted causing data distortion or playback failure
Solution Approach 1:
The system performs preliminary action by storing previous audio clock data in a buffer before transmission. When noise is detected in the current audio stream, the system can refer back to the previously stored clean data, allowing continuous operation while preventing corrupted bits from causing data distortion or playback failure
3Adaptability or versatility
If the audio clock is not directly transmitted, then the system can be more flexible in clock recovery, but the audio clock becomes misaligned with the data causing decoding errors
Solution Approach 1:
The decision unit serves as an intermediary that receives both the currently recovered audio clock and the previously stored clock information. It compares these two sources to detect misalignment and noise, then selects the appropriate clock data for transmission, thereby maintaining flexibility in clock recovery while ensuring precise alignment with the data
Data Source
AI summary
An apparatus and method for regenerating S/PDIF data is disclosed. The apparatus includes a buffer for buffering sample words of the data units; a decision unit for receiving control words of the data units and outputting a selected control word according to a current control word of a current data unit and a previous control word of a previous data unit; and a transmitter for generating the bitstream of the first digital interconnect format according to the sample words of the data units and the selected control words outputted from the decision unit.