SegDSP

Go SDR demodulator. Connects to a radioserver instance for IQ data and provides a web-based spectrum display with demodulated audio output.

Features

• Wideband and narrowband FM demodulation with de-emphasis
• AM demodulation with AGC
• Real-time FFT waterfall via WebSocket
• Squelch with automatic recording
• Cross-platform single binary (static content embedded via go:embed)
• Multi-arch Docker images

Quick Start

go build -o segdsp .

# FM radio
segdsp -channelFrequency 106300000 -demodMode FM -fmDeviation 75000 -filterBandwidth 120000 -radioserver localhost:4050

# AM radio
segdsp -channelFrequency 145570000 -demodMode AM -filterBandwidth 15000 -radioserver localhost:4050

Requires a running radioserver instance.

Docker

Images are published to Docker Hub on every push to master:

docker run -e RADIOSERVER=host.docker.internal:4050 racerxdl/segdsp

Available tags: latest, amd64-latest, arm64v8-latest, arm32v6-latest

Presets

Instead of setting individual flags, use a preset:

segdsp -preset wbfm -channelFrequency 106300000
segdsp -preset nbfm -channelFrequency 145570000
segdsp -preset am   -channelFrequency 145570000

Configuration

Argument	Environment variable	Type	Default	Description
-channelFrequency	CENTER_FREQUENCY	number	106300000	Channel (IQ) Center Frequency in Hz
-radioserver	RADIOSERVER	string	localhost:4050	radioserver address
-demodMode	DEMOD_MODE	string	FM	Demodulator mode: FM, AM
-preset	PRESET	string	none	Preset: wbfm, nbfm, am
-outputRate	OUTPUT_RATE	number	48000	Output audio sample rate in Hz
-filterBandwidth	FS_BANDWIDTH	number	120000	First stage filter bandwidth in Hz
-decimationStage	DECIMATION_STAGE	number	3	Channel decimation stage (decimation = 2^d)
-fftFrequency	FFT_FREQUENCY	number	106300000	FFT center frequency in Hz
-fftDecimationStage	FFT_DECIMATION_STAGE	number	1	FFT decimation stage
-displayPixels	DISPLAY_PIXELS	number	512	FFT display width in pixels
-httpAddr	HTTP_ADDRESS	string	localhost:8080	HTTP service address
-fmDeviation	FM_DEVIATION	number	75000	FM max deviation in Hz
-fmTau	FM_TAU	number	0.000075	FM de-emphasis tau (0 to disable)
-squelch	SQUELCH	number	-150	Squelch threshold in dB
-squelchAlpha	SQUELCH_ALPHA	number	0.001	Squelch filter alpha
-amAudioCut	AM_AUDIO_CUT	number	5000	AM audio low-pass cut in Hz
-stationName	STATION_NAME	string	SegDSP	Station name / callsign
-record	RECORD	bool	false	Record audio when not squelched
-recordMethod	RECORD_METHOD	string	file	Recording method (file)
-webCanControl	WEB_CAN_CONTROL	bool	false	Allow web UI to control settings
-tcpCanControl	TCP_CAN_CONTROL	bool	true	Allow TCP clients to control settings
-cpuprofile		string		Write CPU profile to file

Development

go build -o segdsp .
go test -v -race ./...
golangci-lint run

License

Apache 2.0