|
RF
Phase and Frequency Variations Detection
This tutorial illustrates another capability of EMCExplorer by detecting RF signal phase and frequency variations. The approach extracts the RF signal discontinuities caused by phase and frequency variations, and displays the discontinuity with wavelet transform coefficient image and curve, correlating to original signal.
1. Load Data Files
RF signal can be loaded with Open File. Although loading multi signals is allowed, in most
situations, single RF signal will be studied for phase and frequency variation thus single data is loaded. The maximum data file length follows
this equation: Maximum data length = (30 - loaded data files number) x
16384 If the data file length is longer than above Maximum Length, only the first Maximum Length data will be imported into the program for analysis.
2. Select Working Mode
After the data are loaded, enable the Jitter button in Working-Mode panel. The control panels
below the Working-Mode panel will be updated automatically into the jitter panels including the RF Phase & Frequency Variations panel.
3. Jitter Configurations
Enable Clock button for RF signal analysis. Choosing the RF signal from the Data-Selection Box, the program will calculate the RF frequency and display it at Ideal-Clock-Frequency box.
4. RF signal Phase and Frequency Variation Analysis
Theoretical research and practical experiment confirm that a discontinuity at original RF waveform will make a rapid increase of wavelet transform coefficient, and the magnitude of the coefficient spike can be correlated to the original phase discontinuity value in original RF signal. This phenomenon makes up the keystone of the RF signal Phase and Frequency Variation Analysis foundation in this
program. Selecting RF-Phase-&-Frequency-Variation option from the Display-Selection box in Jitter-Analysis panel,
the program will perform a wavelet transform on RF signal and as a result, the Phase-discontinuities-detection box will list ten index numbers referring the ten time moments where the most heavy phase or frequency changes happen, indicating the most possible discontinuities of analyzed data. Clicking Scan button will enable the different index from Phase-discontinuities-detection box in turn, causing the waveform in the main screen
to change in accord with the enabled index. Dragging the
track-bar slider
of Waveform Slipping can move the waveform in the main screen in accord with
track-bar slider position. The main screen always displays at a three window mode: the wavelet transform coefficient image is shown in middle window with the original RF signal displayed at top window and the wavelet transform coefficient curve displayed at bottom window where the coefficient spike correlating to index at Phase-discontinuities-detection box appears at the center,
except that the coefficient spike is located near the edge of RF signal.
|
