Mueller-Muller Timing Detector Gain Calibration for Stable Jitter Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mueller-Muller timing error detectors suffer from gain uncertainty due to sensitivity to received signal amplitude and channel characteristics, leading to unpredictable Sinusoidal Jitter Tolerance (SJTol) performance and instability in timing tracking loops.
Innovation Solution
A secondary timing path is introduced to calibrate and adjust the gain of the Mueller-Muller timing error detector, using a secondary MM TED with deliberately offset samples to compare with the main error signal, allowing adaptive adjustment of the scaling factor to normalize the detector slope and improve SJTol performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a standard Mueller-Muller timing error detector is used, then the circuit complexity is low, but the gain is uncertain due to sensitivity to received signal amplitude and channel characteristics
Solution Approach 1:
The patent implements a feedback mechanism where the output of the secondary MM TED is fed back to adjust the gain of the main MM TED. The secondary path processes delayed versions of the input signal and compares its output with the main path output, generating a correction signal that is applied back to the main detector through a gain adjustment block. This closed-loop feedback stabilizes the overall gain despite variations in signal amplitude and channel characteristics.
Solution Approach 2:
The patent introduces a secondary MM TED path as an intermediary component that does not directly participate in the main timing detection but serves to monitor and adjust the gain of the main detector. This intermediary path processes a delayed version of the input signal and provides gain correction information, acting as a mediator between the variable input conditions and the main detection function.
2Reliability
If the gain of the Mueller-Muller timing error detector is adjusted to improve SJTol performance, then the Sinusoidal Jitter Tolerance improves, but the loop response becomes unpredictable
Solution Approach 1:
The feedback mechanism continuously monitors the output of the main MM TED and adjusts the gain dynamically to maintain optimal SJTol performance. By comparing the main path output with the secondary path output (which processes delayed signals), the system generates real-time gain correction signals that stabilize the loop response while maintaining improved jitter tolerance.
Solution Approach 2:
The patent dynamically changes the gain parameter of the MM TED based on real-time signal conditions. The secondary path detects variations in signal amplitude and channel characteristics, and adjusts the main detector's gain parameter accordingly. This adaptive parameter adjustment maintains stable loop response while optimizing SJTol performance under varying operating conditions.
3Reliability
If a secondary timing path is added to calibrate gain, then the gain stability improves, but the device complexity increases
Solution Approach 1:
The patent segments the timing detection function into two separate paths: a main MM TED for primary timing detection and a secondary MM TED for gain calibration. The secondary path is dedicated solely to monitoring and adjusting gain, while the main path handles timing detection. This functional segmentation allows each path to be optimized for its specific purpose while working together to achieve stable gain and accurate timing.
Solution Approach 2:
The secondary MM TED path serves multiple functions: it monitors signal amplitude variations, detects channel characteristic changes, generates gain correction signals, and stabilizes the main detector's performance. By making this secondary path multi-functional, the patent achieves comprehensive gain stabilization without requiring multiple separate calibration circuits, thereby limiting the increase in overall device complexity.
Data Source
AI summary
Apparatus and methods calibrate and control detector gain in a Mueller-Muller timing detector. A main signal path includes a Mueller-Muller based timing error detector (MM TED). The main signal path generates a main error signal for clock recovery. A secondary signal path that includes a secondary MM TED. Each signal path samples soft symbols from a received signal. The sampling of the secondary MM TED is deliberately offset in time. A scale factor applied to the main error signal and to a secondary error signal is adaptively adjusted based on a comparison between the main error signal and the secondary error signal.