Shared FIR Sample Rate Conversion for Independent Audio Streams
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Solution Overview
Problem
Existing sample rate conversion systems require separate synchronizers for each independent data stream, leading to inefficiencies in multichannel applications where multiple streams with different sample rates need to be synchronized.
Innovation Solution
A sample rate conversion system with a shared memory block, a shared finite impulse response (FIR) filter, and a selector (arbitrator) that manages the filtering of input streams using adaptive filter coefficients and a first-come-first-served principle, allowing multiple streams to share resources and minimize hardware footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate synchronizers are used for each independent data stream, then each stream can be processed independently, but the hardware footprint and system complexity increase significantly
Solution Approach 1:
The patent merges multiple independent synchronizer functions into a single shared synchronizer that can service multiple input streams. The storage means, controller means, and resampling means are shared resources that handle multiple streams sequentially, eliminating the need for separate synchronizer hardware for each stream while maintaining independent processing capability.
Solution Approach 2:
The synchronizer is designed as a universal device that can process multiple different input streams with different sample rates. The controller means responds to activation signaling from multiple streams and dynamically configures the resampling operation for the selected stream, making the same hardware perform multiple functions for different streams.
2Device complexity
If a shared synchronizer is used for multiple input streams, then hardware footprint is reduced, but access to shared resources requires coordination and arbitration
Solution Approach 1:
The selector means acts as an intermediary or arbitrator between multiple input streams and the shared synchronizer resources. It receives activation signaling from multiple streams, selects which stream to service next, and coordinates access to the storage means, controller means, and resampling means, eliminating the need for complex arbitration logic in each stream processor.
3Device complexity
If multiple streams share a single resampling operation, then hardware resources are optimized, but only one stream can be processed at a time
Solution Approach 1:
The shared synchronizer processes multiple input streams in a periodic or sequential manner rather than true parallel processing. The selector means cycles through active streams, allocating the shared resampling resources to each stream in turn based on activation signaling, achieving resource optimization while maintaining acceptable throughput for all streams.
Data Source
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AI summary
A system is presented for sample rate conversion of an input stream of digital data among a plurality of input streams sampled at a different input. The system (1) comprises - storage means (3) for storing input samples of the input streams, - controller means (5) arranged for receiving activation signalling (4) related to the input streams and for outputting for the input streams an indication (6,8) of sampling instants for said output stream at said output sampling rate, - resampling means (7) arranged for receiving input samples from the storage means and for filtering the received input samples with an adaptive set of filter coefficients to produce an output stream at an output rate. The system further comprises a selector means (9) for receiving the activation signalling related to the input streams, for selecting among the input streams an input stream to be sample rate converted, said selector means being arranged for outputting a signal (10) indicative of the selected input stream and for outputting signalling (12) for selecting the corresponding indication of sampling instants, so that filter coefficients for performing resampling in the resampling means can be generated.