Switched Bleed Currents for Low-ISI Multiplexer Settling
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Solution Overview
Problem
In coherent optical communication systems, high-speed signal conversions between digital and analog formats are challenging due to issues like intersymbol interference (ISI), voltage errors from clock jitter, and high power consumption, especially when distributing clocks over large areas.
Innovation Solution
Implementing a method that uses switched DC bleed currents to maintain a constant multiplexer current, cancel common-mode currents, and reduce ISI by alternating dummy bleed currents in opposite phases, allowing for faster settling and lower power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-speed signal conversions are implemented in coherent optical communication systems, then data transmission speed is improved, but intersymbol interference and voltage errors increase
Solution Approach 1:
The patent applies periodic action by using alternating phases of dummy bleed currents that switch between even and odd branches at regular intervals. This periodic switching maintains constant total current while canceling common-mode currents, thereby reducing intersymbol interference and voltage errors during high-speed signal conversions.
Solution Approach 2:
The patent changes the parameter of current distribution by dynamically switching dummy bleed currents between different branches based on phase timing. This parameter change ensures that while individual branch currents vary, the total multiplexer current remains constant, maintaining signal integrity during high-speed operations.
2Reliability
If dummy bleed currents are used to reduce ISI, then signal accuracy is improved, but power consumption increases
Solution Approach 1:
The patent merges the functionality of multiple dummy bleed currents into a unified system where currents in even and odd branches work together. By coordinating these currents to cancel common-mode components, the system achieves better signal accuracy while the alternating phase operation ensures efficient power utilization rather than continuous dissipation.
Solution Approach 2:
The periodic switching of dummy bleed currents between branches ensures that power is utilized efficiently. The alternating phases allow the system to maintain signal accuracy through common-mode current cancellation while avoiding continuous power dissipation, as the dummy currents are activated only when needed for balancing.
3Area of stationary object
If clock distribution is extended over large areas, then system coverage is improved, but voltage errors from clock jitter increase
Solution Approach 1:
The patent changes the timing parameters of dummy bleed current switching to be synchronized with the clock signal phases. This parameter adjustment ensures that even when clocks are distributed over large areas and subject to jitter, the alternating phase operation maintains consistent current balancing, reducing voltage errors and maintaining signal accuracy.
4Loss of time
If switched bleed currents are used to maintain constant multiplexer current, then settling time is reduced, but circuit complexity increases
Solution Approach 1:
The patent segments the dummy bleed current circuitry into separate even and odd branch components, each controlled by phase-specific signals. This segmentation allows independent optimization of each branch while maintaining overall current constancy, reducing settling time without requiring a completely complex unified control mechanism.
Data Source
AI summary
A method, system, and apparatus for multiplexing comprising feeding a signal into a sampler, splitting a first signal into an even branch at a first set of times, splitting a second signal into an odd branch at a second set of times, feeding a switch bleed current into the first branch at the second set of time and feeding the switch bleed current into the second branch at the first set of time.