transmit-test

Transmit PTT Signal Integrity Test

Run transmit_test.py to verify the radio transmitter's I/Q outputs are clean sinusoids across repeated PTT cycles. This detects intermittent failures where PTT activation produces discontinuities, zeroed channels, or distorted waveforms.

Hardware requirements

An Analog Discovery 2 must be connected via USB with the following wiring:

• DIO-0 controls PTT (LOW = transmit, HIGH = off)
• W1 drives the microphone input (500 Hz, 100 mV sine)
• Scope Ch1/Ch2 read the I and Q quadrature outputs

Running the test

Run from the transmit directory:

cd /home/oliver/Sync/Ham/T41/Software/Phoenix/code/test/transmit
python3 transmit_test.py -n $iterations

If no iteration count is provided, default to 5 for a quick smoke test. For a full test run, use -n 100.

Interpreting results

The program exits with code 0 if all iterations pass, or code 1 if any fail. Each iteration reports:

• PASS/FAIL status
• RMS amplitude of each channel (expect 50-200 mV; below 5 mV = dead channel)
• SNR in dB (expect >40 dB; below 20 dB = distorted)
• Dominant frequency (expect 500 Hz)

Failed iterations automatically save raw waveform data to failures/ as .npz files along with a png plot.

Typical failure modes

Symptom	Likely cause
RMS near zero on one/both channels	I/Q output not starting after PTT
Low SNR, correct frequency	Discontinuity or glitch in waveform

Common options

Flag	Default	Description
-n, --iterations	100	Number of PTT cycles
--settle-time	0.5	Seconds after PTT engage before capture
--acquire-time	0.1	Capture duration in seconds
--interval	0.5	Seconds between iterations
--min-snr	20.0	Minimum SNR (dB) to pass
--save-all	off	Save waveform data for passing iterations too

If the test fails

1. Report the summary line and any failure reasons to the user.
2. If .npz files were saved, you can load and inspect them:

   import numpy as np
   data = np.load("failures/fail_iter0001_TIMESTAMP.npz")
   ch1, ch2 = data["ch1"], data["ch2"]  # I and Q waveform arrays
   sr = float(data["sample_rate"])       # 100000 Hz
   

3. Do NOT attempt to fix transmit_test.py based on test failures -- the failures indicate a hardware/firmware problem in the radio, not a bug in the test program.

If the AD2 is not connected

The program will print Failed to open device and exit with code 1. This is expected if no AD2 is plugged in. Do not retry -- inform the user that the hardware is not available.