Mode Signal workbench

Signal workbench: analyse, demodulate and read any recording.

Group	General & tools
Default frequency	100 MHz
Default sample rate	2 Msps
In the mode list	Files: audio and IQ

Step-by-step: Tutorial-Signal-workbench

What Signal workbench is

The Signal workbench takes a recording apart without a radio: a spectrogram, measurements, demodulators and the recovered bits.

Frequencies and settings

No radio needed: a recording opened from a file: audio (WAV, MP3, FLAC, OGG, M4A: a real signal, or a stereo file as I/Q) or IQ (.cs8 .cu8 .cf32 .ci16 .cu16, SigMF, IQ WAV).

Setting	Value
Start frequency	100 MHz
Tuning range of the mode table	0.1 to 6000 MHz
Sample rate asked	2 Msps
Lowest working rate	8 ksps
Channel width	2 MHz

OnAir takes any frequency you type; the numbers above are the mode's starting point and the range its table describes. In the app the shortcut label is Files: audio and IQ.

What OnAir shows

Waveform and spectrogram with cursors and a time and band selection; peaks, bandwidth (-3 dB, -20 dB, 99 %), carrier offset, SNR, symbol rate, modulation hints, power over time and bursts; AM, FM, SSB, CW, ASK/OOK, 2-FSK / 4-FSK, AFSK (Bell 202, 103 ...), BPSK / QPSK / 8PSK, MSK / GMSK demodulators with eye, constellation and the recovered bit stream (invert, differential, NRZI, Manchester, bit order, pattern search); listening and export.

The mode's own tab has these screens: Signal, Measure, Demodulate, Bits, Export. The other tabs (Overview, Receiver, Scan, History) are described on the Main window page.

Tips and caveats

• This is a tool for looking at the spectrum and recordings, not a decoder of one standard.
• Which radio: Usually yes for narrowband signals: an RTL-SDR tunes roughly 24 MHz to 1.7 GHz at up to about 2.4 Msps. Wide signals such as TV channels need a faster radio, and OnAir says next to the source what the selected radio can do.
• Try it without a radio: most modes include a built-in synthetic test signal, so you can open the screen and try the controls first.
• Receiving and the law: These tools only look at the spectrum and listen. Receiving is legal in most countries, but laws differ on what you may use the content for. See Legal.

Related pages

• Record IQ, then the Signal workbench
• All modes, General & tools
• Supported radios, Troubleshooting, FAQ
• More in General & tools: General receiver, Spectrum explorer, Spectrum analyser