DDS Phase Control Using Stored High-Resolution Phase Information
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Solution Overview
Problem
Existing Direct Digital Synthesizer (DDS) systems face challenges in finely controlling phase due to bit resolution limitations and experience transient issues when phase or frequency is changed, affecting impedance measurements and amplifier gain accuracy.
Innovation Solution
A phase controlling apparatus that includes a phase information storing section and a phase controlling section, allowing for flexible phase control of DDS signals by using additional phase information with higher resolution than the phase offset adjusting register, and utilizing a clock signal to manage signal output timing, thereby reducing transient periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the phase of the DDS is controlled using the phase offset adjusting register, then the phase can be adjusted, but the phase control precision is limited by the bit resolution of the register
Solution Approach 1:
The phase control function is divided into two independent parts: the original phase offset adjusting register and the newly added phase information storing section. This segmentation allows each part to have different resolutions - the register maintains its original bit width while the storing section provides additional precision through higher-resolution phase information storage, thereby improving overall phase control precision without increasing the complexity of the register itself
Solution Approach 2:
A phase combining section is introduced as an intermediary component that receives phase information from both the phase offset adjusting register and the phase information storing section. This mediator combines the phase information from both sources to generate the final phase control signal, enabling the system to achieve higher precision than either component could provide alone while maintaining the original register structure
2Adaptability or versatility
If the phase or frequency of the DDS is changed, then the signal can be controlled, but a transient occurs in the waveform that delays stabilization
Solution Approach 1:
The system pre-calculates and stores optimal phase information in the phase information storing section before phase or frequency changes are needed. When a change is required, the pre-prepared phase information is immediately applied through the phase combining section, eliminating the need for gradual adjustment and significantly reducing the transient period while maintaining full control flexibility
Solution Approach 2:
The phase combining section dynamically adjusts the combination of phase information from the register and the storing section based on real-time control requirements. This dynamic adjustment allows the system to rapidly transition between different phase and frequency states without experiencing prolonged transients, as the combining logic adapts instantly to new conditions
3Reliability
If a Band Pass Filter is disposed at the output of the DDS to control phase changes, then phase control is achieved, but the waveform stability time is increased due to transient response
Solution Approach 1:
The essential phase control function is extracted from the Band Pass Filter and implemented through the digital phase combining section. By removing the reliance on the BPF's transient response for phase control, the system achieves phase adjustment without the prolonged stabilization time that would otherwise be required for the filter to settle, while maintaining control reliability through the digital phase combination mechanism
Data Source
AI summary
A phase controlling apparatus is disclosed. The phase controlling apparatus controls phases of signals which are output from a plurality of signal sources corresponding to first phase information which indicates a phase of a predetermined signal. The phase controlling apparatus includes a phase information storing section and a phase controlling section. The phase information storing section stores second phase information which indicates a phase of a signal which is output from each of the plurality of signal sources. The phase controlling section changes a phase of a signal which is output from at least one of the plurality of signal sources corresponding to the second phase information stored in the phase information storing means to control the difference of phases of signals which are output from the plurality of signal sources.