Sync Machine Data Pull Flow Control Synchronization
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Solution Overview
Problem
Existing systems face challenges in synchronizing digital logic elements with a trigger signal, particularly in communication systems like CDMA, where the propagation of pull signals in the opposite direction of data samples introduces delays, making it difficult to initiate processing at the exact time of the trigger signal.
Innovation Solution
The implementation of a sync machine that uses pull signals to regulate data generation and propagation through shift registers, ensuring that data is available and processed correctly at the time of the trigger signal, with the sync machine asserting and suspending the pull signal to coordinate data flow into a digital-to-analog converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pull signals are propagated through a chain of logic devices to control data generation, then data flow control is achieved, but synchronization delay occurs because the pull signal travels in the opposite direction of data samples
Solution Approach 1:
The sync machine asserts the pull signal in advance before the trigger signal arrives, allowing data to be prepared and positioned in the data path ahead of time. This preliminary assertion of the pull signal enables the system to eliminate synchronization delay by having data ready when the trigger signal occurs, rather than waiting for pull signals to propagate backward from the DAC.
2Reliability
If the pull signal is continuously asserted to maintain data flow, then data availability is ensured, but the ability to synchronize precisely with the trigger signal is reduced
Solution Approach 1:
The pull signal is asserted periodically rather than continuously - specifically, it is asserted in advance of the trigger signal, then suspended when the mark signal indicates data has reached the DAC, and reasserted after the trigger signal occurs. This periodic assertion pattern maintains data availability while achieving precise timing synchronization with the trigger signal.
Solution Approach 2:
The sync machine uses feedback from the mark signal to control pull signal assertion. When the mark signal indicates that data has reached the DAC, the sync machine suspends the pull signal. This feedback mechanism ensures data availability is maintained only when needed, enabling precise timing control while avoiding unnecessary data generation.
3Ease of operation
If shift registers are used to buffer data between the signal source and DAC, then data flow control is improved, but circuit complexity increases
Solution Approach 1:
The data path is segmented into discrete register stages between the signal source and DAC. Each register can be independently controlled by the pull signal, allowing precise control of data flow through the pipeline. This segmentation enables efficient data buffering and timing control without requiring complex control logic, as each stage simply responds to the pull signal assertion.
Data Source
AI summary
In one embodiment, a system comprises a signal source for generating a digital signal in response to a data pull signal; a digital-to-analog converter (DAC); a first plurality of shift registers for registering digital words of the digital signal before receipt by the DAC; a synchronizing logic element for generating the data pull signal, wherein the synchronizing logic element initially generates the data pull signal to cause the signal source to generate a number of data words, ceases communication of the data pull signal upon receipt of a mark signal, and resumes communication of the data pull signal upon receipt of a trigger signal; and a second plurality of shift registers for registering the mark signal before communication to the synchronizing logic element, wherein the first and second plurality of shift registers are enabled by the data pull signal.