Real-Time Spectrum Analyzer FFT Processing Architecture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing oscilloscope's real-time spectrum analysis mode is limited by the need for higher processing bandwidth in the plotter to 'catch up' with the acquisition memory, restricting the maximum bandwidth of the analysis due to periodic reads synced with the video frame rate, which also prevents frequency-domain triggering.
Innovation Solution
Implementing a real-time spectrum analyzer with an analog-to-digital converter, digital down-converter, fast Fourier transform unit, and acquisition memory, where the FFTs are computed and stored in real-time, allowing the plotter to read and generate display data non-real-time, thereby eliminating the need for extra bandwidth and enabling frequency-domain triggering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the plotter reads data periodically synced to video frame rate, then display stability is improved, but processing bandwidth must be higher than acquisition bandwidth to catch up
Solution Approach 1:
The system pre-processes and stores FFT results in acquisition memory during the acquisition phase, so that when the plotter needs data for display, pre-computed frequency domain data is already available. This eliminates the need for the plotter to catch up by processing at higher speeds, as the heavy computational work (FFT) is performed in advance during acquisition.
2Speed
If periodic reads are synced to video frame rate, then display synchronization is improved, but maximum bandwidth of RTSA is limited
Solution Approach 1:
FFT computations are performed in advance during the acquisition phase and results are stored in acquisition memory. This preliminary computation allows the system to support higher acquisition bandwidths without requiring the plotter to process data at equally high speeds, thus breaking the bandwidth limitation while maintaining display synchronization.
3Speed
If the plotter processes data in real-time, then processing speed is improved, but additional hardware and power are required
Solution Approach 1:
The system combines the FFT processing function with the acquisition phase, using the same hardware resources (ADC, processor, memory) for both acquisition and frequency domain analysis. By merging these functions and performing FFT during acquisition, the system achieves real-time processing capability without requiring separate dedicated hardware for the plotter, thus avoiding additional hardware and power requirements.
Data Source
AI summary
A real-time spectrum analyzer (RTSA) includes an analog-to-digital converter (ADC) configured to convert in real-time an input analog signal into a digital input data stream, a digital down-converter (DDC) configured to down-convert in real-time the digital input data stream into a down-converted input data stream, a fast Fourier transform (FFT) unit configured to generate in real-time FFTs of the down-converted input data stream, an acquisition memory circuit configured to store in real-time the FFTs generated by the FFT unit, and an analyzer configured to read in non-real time the FFTs stored in the acquisition memory.