SineArrayGAM

SineArrayGAM is a helper GAM bundled with the UDPStreamer library. It fills a float32 output array with a continuous sinusoidal waveform, maintaining phase continuity across RT cycles. It is intended for testing and demonstrating the UDPStreamer's packed-burst signal capability.

Library: The class is compiled into UDPStreamer.so alongside the UDPStreamer DataSource. A SineArrayGAM.so → UDPStreamer.so symlink is required for MARTe2's auto-loader (created automatically by Test/MARTeApp/run.sh).

Configuration

+Ch1GAM = {
    Class        = SineArrayGAM
    Frequency    = 1000.0       // Signal frequency [Hz]  (default: 1.0)
    Amplitude    = 1.0          // Peak amplitude           (default: 1.0)
    Offset       = 0.0          // DC offset                (default: 0.0)
    Phase        = 0.0          // Initial phase [radians]  (default: 0.0)
    SamplingRate = 1000000.0    // Sample rate [Hz]         (default: 1000000.0)
                                //   Must match the SamplingRate declared in the
                                //   UDPStreamer signal config.

    OutputSignals = {
        Ch1 = {
            DataSource       = DDB
            Type             = float32
            NumberOfDimensions = 1
            NumberOfElements = 1000   // N samples per RT cycle
        }
    }
}

Parameters

Parameter	Type	Default	Description
`Frequency`	float64	1.0	Signal frequency in Hz
`Amplitude`	float64	1.0	Peak amplitude (half peak-to-peak)
`Offset`	float64	0.0	DC offset added to every sample
`Phase`	float64	0.0	Phase shift in radians
`SamplingRate`	float64	1 000 000.0	Sample rate in Hz; must be > 0

Output signal

Exactly one output signal of type float32 is required. The signal must have NumberOfDimensions = 1 and NumberOfElements = N where N ≥ 1.

Waveform formula

Each Execute() call fills elements [0 .. N-1] using:

v[k] = Amplitude × sin(2π × Frequency × (offset_total + k) / SamplingRate + Phase) + Offset

where offset_total is a cumulative sample counter that increments by N after each call. This guarantees a gapless, phase-continuous waveform across RT cycles.

Bandwidth and fragmentation

For a 1 MSps burst at 10 kHz RT rate with 1000 samples per cycle:

N = SamplingRate / RT_rate = 1 000 000 / 1000 = 1000 samples per cycle
Wire bytes = 1000 × 4 (float32) = 4000 B per channel per cycle
At 10 kHz: 4000 × 10 000 = 40 MB/s raw (UDP, before quantization)

Using QuantizedType = uint16 halves the wire bandwidth to 20 MB/s. With MaxPayloadSize = 1400 the 4 000-byte payload spans 3 UDP datagrams (ceil(4008 / 1383) = 3).

Example: two-channel quadrature pair

+Ch1GAM = {
    Class = SineArrayGAM
    Frequency = 1000.0; Amplitude = 1.0; Phase = 0.0; SamplingRate = 10000000.0
    OutputSignals = {
        Ch1 = { DataSource = DDB; Type = float32; NumberOfDimensions = 1; NumberOfElements = 1000 }
    }
}

+Ch2GAM = {
    Class = SineArrayGAM
    Frequency = 1000.0; Amplitude = 1.0; Phase = 1.5708; SamplingRate = 10000000.0
    OutputSignals = {
        Ch2 = { DataSource = DDB; Type = float32; NumberOfDimensions = 1; NumberOfElements = 1000 }
    }
}

This produces two signals 90° out of phase, useful for verifying IQ-style signal chains.

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