Mobile TV Receiver Synchronization Using Wideband-to-Narrowband Acquisition
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Solution Overview
Problem
Existing mobile television receivers face challenges in accurately synchronizing with ISDB-T signals, particularly due to coarse frequency offset issues, which can lead to inefficiencies in tuner design and increased complexity and cost, especially when receiving only one segment of a 13-segment signal.
Innovation Solution
The implementation of a wideband filter for coarse frequency estimation followed by a narrowband filter to improve synchronization, allowing for detection of the mode and guard within the ISDB-T signal, and subsequent filtering out of unwanted segments, thereby enhancing tuner accuracy and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multiple segment tuner is used to receive all 13 segments, then the receiver can accommodate various reception modes, but the tuner becomes more complex in operation and construction and more expensive
Solution Approach 1:
The patent divides the 13-segment signal reception into two distinct phases: a wideband acquisition phase that processes all 13 segments for synchronization, and a narrowband reception phase that processes only the desired segment. This segmentation allows the tuner to maintain simplicity while achieving multi-mode compatibility through sequential operation rather than simultaneous capability.
2Adaptability or versatility
If a multiple segment tuner is used to receive all 13 segments, then the receiver can accommodate various reception modes, but the cost increases
Solution Approach 1:
The patent segments the signal processing into wideband and narrowband stages, allowing a single, simpler tuner to perform multiple functions sequentially. The wideband stage uses all 13 segments for acquisition, then the system switches to narrowband mode for the desired segment only, eliminating the need for expensive multiple-tuner configurations while maintaining versatility.
3Measurement precision
If a more accurate tuner is used to improve synchronization, then the synchronization performance improves, but the tuner becomes more complex in operation and construction
Solution Approach 1:
The patent applies preliminary wideband filtering and coarse frequency offset correction using all 13 segments before the main narrowband reception. This preliminary action establishes accurate synchronization parameters (frequency offset, mode, guard interval) that enable the subsequent narrowband tuner to operate with high precision using a simpler, less expensive design.
4Productivity
If only one segment is received, then the number of prefix and data samples in one symbol becomes very small, but detecting the mode and guard becomes difficult
Solution Approach 1:
The patent merges the detection of mode and guard interval parameters from all 13 segments during the wideband acquisition phase, rather than attempting to detect them from a single segment. By combining information across all segments, the system accumulates sufficient samples to reliably determine synchronization parameters, which then guide the narrowband reception of the desired segment.
Data Source
AI summary
A method for synchronizing a receiver to a received signal begins by down-converting the received signal to a first baseband signal. A coarse frequency offset (CFO) of the first baseband signal is determined and is applied to the down-converting of the received signal to a second baseband signal. A fine frequency offset (FFO) of the second baseband signal is determined. The receiver is synchronized to the received signal using the CFO and the FFO.