This measurement is captured on an external USB flash drive. The captured data file cannot be recalled and displayed on the instrument screen.
The LMR Master can capture and log TETRA IQ data to a USB flash drive.
1. From the Frequency main menu, set the receiver frequency (Rx Freq).
2. Insert a formatted USB flash drive into the LMR Master, and from the Measurement main menu, press the TETRA IQ Capture submenu key. After approximately 10 seconds, the instrument displays a message that the capture is complete.
The IQ data is sampled at 4,800 x 11 samples per second. The saved file has an ASCII header and binary data (see Figure: IQ Capture for an example). The data is written in 24‑bit two’s complement integer format. Interleaved Delta Phase (I) data then Magnitude (Q) data is captured. The file is intended for post‑processing in MATLAB or other data analysis software.
The file will be written to a data stamped folder inside the /usr folder on the root level of the USB flash drive. The file is named:
IQ_CAPTUREyearmonthdaytime.TETRA
Note
There is no display menu for TETRA IQ Capture. The LMR Master will continue to display the previous measurement screen during IQ Capture.
IQ Capture
1.
ASCII header listing parametric information
2.
Binary data in 24‑bit two’s complement integer format
