Recording a Waveform

Use the pshell recordstart and recordstop commands to capture acoustic waveform data on the modem.

Select the recording mode. Use 0 for passband recording or 1 for baseband recording:
```
RecordMode 0
```
Start recording. Specify a base filename and the file-segment duration in seconds:
```
recordstart /captures/harbor_test 60
```
The modem appends a timestamp and the .wav extension to the filename. The duration controls how frequently a continuous recording is divided into new files; it does not set the total recording time.
Allow the recording to run for the required amount of time.
Stop and close the recording:
```
recordstop
```

Playing the Recorded Waveform

The playback mode should match the mode used to create the recording.

Select the playback mode. Use 0 for passband playback or 1 for baseband playback:
```
PlayMode 0
```
Start playback using the complete recorded filename and a scale factor. Begin with a conservative scale such as 0.5:
```
playstart /captures/<recorded-filename>.wav 0.5
```
Allow the file to finish, or stop playback manually:
```
playstop
```

note

Baseband recording can interfere with normal modem operation because it shares signal-processing resources with the modem. Use passband mode unless baseband samples are specifically required.

Playing the Recorded Waveform​

Playing the Recorded Waveform