SM200C Streaming IQ – no Triggers

I’m currently trying to implement streaming IQ with trigger inputs on an SM200C.

A few years back we had implemented this on some SM200B’s and it worked as expected (a 1PPS into the GPIO port of the signal hound showed up as expected).

Now we have a new application, and can’t seem to get the triggers to work.

If I sit there and query the GPIO via the API, I see it toggle from 0 to 1 and back and forth as expected. But when I do IQ streaming, the triggers buffer is always returned as zeros.

I’ve stepped through every function, and they all return smNoError, so I don’t see what’s going wrong here. Tried a second SM200C and have the same issue.

sm_api.dll from Aug 21, 2025.

private void SetupRFSamplerForIQStreaming()
{
AppLogger.Info(“Configuring Signal Hound for IQ Streaming”);
try
{
try { _SH.AbortMeasurements(); } catch { }
_SH.SetGpioDirections(true, true); //trying this to see if we get triggers..
// _SH.SetGPSTimebaseUpdate(); //Sets the Timebase to begin updating with GPS time if available

_SH.SetIQCenterFreq(_RXCenterFreqInMHz * 1.0e6);
_SH.SetIQBandwidth(_RXBandwidthInMHz * 1.0e6);
_SH.SetRefLevel(-10);
_SH.SetIQDataType(SmDataType.smDataType32fc);
_SH.DisableGPIOSweep();
_SH.SetGPIOTriggerEdgeType(Rising: true);

_SH.SetIQQueueSize((float)(2.62 * 16)); //maximum amount of buffer
_SH.SetIQSampleRate(1); //1 is no decimation, max speed, acts on the powers of 2. We want to go as fast as possible for best time precision

_SH.ConfigureMode(SmMode.smModeIQStreaming);

var f = _SH.GetIQParameters();
RfSampleRateInHz = f[0];
}
catch { AppLogger.Error(“Failure to Configure Signal Hound For IQ Streaming”); }
}

• This topic was modified 1 day, 21 hours ago by kaiser.