TestWaveformSource Class Reference

Helper class for generating test waveforms. More...

#include <TestWaveformSource.h>

Collaboration diagram for TestWaveformSource:

Public Member Functions
	TestWaveformSource (std::minstd_rand &rng)
	TestWaveformSource (const TestWaveformSource &)=delete
TestWaveformSource &	operator= (const TestWaveformSource &)=delete
void	GenerateNoisySinewave (vk::raii::CommandBuffer &cmdBuf, std::shared_ptr< QueueHandle > queue, UniformAnalogWaveform *wfm, float amplitude, float startphase, float period, int64_t sampleperiod, size_t depth, float noise_stdev=0.01)
	Generates a sinewave with AWGN added.
void	GenerateNoisySinewaveSum (vk::raii::CommandBuffer &cmdBuf, std::shared_ptr< QueueHandle > queue, UniformAnalogWaveform *wfm, float amplitude, float startphase1, float startphase2, float period1, float period2, int64_t sampleperiod, size_t depth, float noise_stdev=0.01)
	Generates a sum of two sinewaves with AWGN added.
void	GeneratePRBS31 (vk::raii::CommandBuffer &cmdBuf, std::shared_ptr< QueueHandle > queue, UniformAnalogWaveform *wfm, float amplitude, float period, int64_t sampleperiod, size_t depth, bool lpf=true, float noise_stdev=0.01)
	Generates a PRBS-31 waveform through a lossy channel with AWGN.
void	Generate8b10b (vk::raii::CommandBuffer &cmdBuf, std::shared_ptr< QueueHandle > queue, UniformAnalogWaveform *wfm, float amplitude, float period, int64_t sampleperiod, size_t depth, bool lpf=true, float noise_stdev=0.01)
	Generates a K28.5 D16.2 (1000base-X / SGMII idle) waveform through a lossy channel with AWGN.
WaveformBase *	GenerateStep (float vlo, float vhi, int64_t sampleperiod, size_t depth)
	Generates a step waveform.
void	DegradeSerialData (UniformAnalogWaveform *cap, int64_t sampleperiod, size_t depth, bool lpf, float noise_stdev, vk::raii::CommandBuffer &cmdBuf, std::shared_ptr< QueueHandle > queue)
	Takes an idealized serial data stream and turns it into something less pretty.

Protected Member Functions
void	InterpolateSparameters (float bin_hz, size_t nouts)
	Recalculate the cached S-parameters used for channel emulation.

Protected Attributes
std::minstd_rand &	m_rng
	Random number generator.
AcceleratorBuffer< float >	m_forwardInBuf
	Input buffer for FFTs.
AcceleratorBuffer< float >	m_forwardOutBuf
	Output buffer for FFTs.
AcceleratorBuffer< float >	m_reverseOutBuf
	Output buffer for IFFTs.
std::unique_ptr< VulkanFFTPlan >	m_vkForwardPlan
	FFT plan.
std::unique_ptr< VulkanFFTPlan >	m_vkReversePlan
	Inverse FFT plan.
double	m_cachedBinSize
	FFT bin size, in Hz.
AcceleratorBuffer< float >	m_resampledSparamSines
	Serial channel S-parameter real part.
AcceleratorBuffer< float >	m_resampledSparamCosines
	Serial channel S-parameter imaginary part.
ComputePipeline	m_rectangularComputePipeline
	Compute pipeline for our window function.
ComputePipeline	m_channelEmulationComputePipeline
	Compute pipeline for channel emulation.
ComputePipeline	m_noisySineComputePipeline
	Compute pipeline for noisy sinewave generation.
ComputePipeline	m_noisySineSumComputePipeline
	Compute pipeline for noisy sinewave sum generation.
ComputePipeline	m_degradeComputePipeline
	Compute pipeline for DegradeSerialData.
SParameters	m_sparams
	S-parameters of the channel.
size_t	m_cachedNumPoints
	FFT point count as of last cache update.
size_t	m_cachedRawSize
	Input size of FFT as of last cache update.

Detailed Description

Helper class for generating test waveforms.

Used by DemoOscilloscope as well as various unit tests

Member Function Documentation

DegradeSerialData()

void TestWaveformSource::DegradeSerialData	(	UniformAnalogWaveform *	cap,
		int64_t	sampleperiod,
		size_t	depth,
		bool	lpf,
		float	noise_stdev,
		vk::raii::CommandBuffer &	cmdBuf,
		std::shared_ptr< QueueHandle >	queue
	)

Takes an idealized serial data stream and turns it into something less pretty.

The channel is a combination of a lossy S-parameter channel (approximately 300mm of microstrip on Shengyi S1000-2M) and AWGN with configurable standard deviation

Parameters

cap	Waveform to degrade
sampleperiod	Period of the input waveform
depth	Number of points in the input waveform
lpf	True to perform channel emulation, false to only add noise
noise_stdev	Standard deviation of the AWGN, in volts
cmdBuf	Vulkan command buffer to use for channel emulation
queue	Vulkan queue to use for channel emulation

Generate8b10b()

void TestWaveformSource::Generate8b10b	(	vk::raii::CommandBuffer &	cmdBuf,
		std::shared_ptr< QueueHandle >	queue,
		UniformAnalogWaveform *	wfm,
		float	amplitude,
		float	period,
		int64_t	sampleperiod,
		size_t	depth,
		bool	lpf = true,
		float	noise_stdev = 0.01
	)

Generates a K28.5 D16.2 (1000base-X / SGMII idle) waveform through a lossy channel with AWGN.

Parameters

cmdBuf	Vulkan command buffer to use for channel emulation
queue	Vulkan queue to use for channel emulation
amplitude	P-P amplitude of the waveform in volts
period	Unit interval, in femtoseconds
sampleperiod	Interval between samples, in femtoseconds
depth	Total number of samples to generate
lpf	Emulate a lossy channel if true, no channel emulation if false
noise_stdev	Standard deviation of the AWGN in volts
downloadCallback	Callback for download progress

GenerateNoisySinewave()

void TestWaveformSource::GenerateNoisySinewave	(	vk::raii::CommandBuffer &	cmdBuf,
		std::shared_ptr< QueueHandle >	queue,
		UniformAnalogWaveform *	wfm,
		float	amplitude,
		float	startphase,
		float	period,
		int64_t	sampleperiod,
		size_t	depth,
		float	noise_stdev = 0.01
	)

Generates a sinewave with AWGN added.

Parameters

cmdBuf	Vulkan command buffer to use
queue	Vulkan queue to use
wfm	Waveform to fill
amplitude	P-P amplitude of the waveform in volts
startphase	Starting phase in radians
period	Period of the sine, in femtoseconds
sampleperiod	Interval between samples, in femtoseconds
depth	Total number of samples to generate
noise_stdev	Standard deviation of the AWGN in volts

GenerateNoisySinewaveSum()

void TestWaveformSource::GenerateNoisySinewaveSum	(	vk::raii::CommandBuffer &	cmdBuf,
		std::shared_ptr< QueueHandle >	queue,
		UniformAnalogWaveform *	wfm,
		float	amplitude,
		float	startphase1,
		float	startphase2,
		float	period1,
		float	period2,
		int64_t	sampleperiod,
		size_t	depth,
		float	noise_stdev = 0.01
	)

Generates a sum of two sinewaves with AWGN added.

Parameters

cmdBuf	Vulkan command buffer to use
queue	Vulkan queue to use
wfm	Waveform to fill
amplitude	P-P amplitude of the waveform in volts
startphase1	Starting phase of the first sine in radians
startphase2	Starting phase of the second sine in radians
period1	Period of the first sine, in femtoseconds
period2	Period of the second sine, in femtoseconds
sampleperiod	Interval between samples, in femtoseconds
depth	Total number of samples to generate
noise_stdev	Standard deviation of the AWGN in volts

GeneratePRBS31()

void TestWaveformSource::GeneratePRBS31	(	vk::raii::CommandBuffer &	cmdBuf,
		std::shared_ptr< QueueHandle >	queue,
		UniformAnalogWaveform *	wfm,
		float	amplitude,
		float	period,
		int64_t	sampleperiod,
		size_t	depth,
		bool	lpf = true,
		float	noise_stdev = 0.01
	)

Generates a PRBS-31 waveform through a lossy channel with AWGN.

Parameters

cmdBuf	Vulkan command buffer to use for channel emulation
queue	Vulkan queue to use for channel emulation
wfm	Waveform to fill
amplitude	P-P amplitude of the waveform in volts
period	Unit interval, in femtoseconds
sampleperiod	Interval between samples, in femtoseconds
depth	Total number of samples to generate
lpf	Emulate a lossy channel if true, no channel emulation if false
noise_stdev	Standard deviation of the AWGN in volts
downloadCallback	Callback for download progress

GenerateStep()

WaveformBase * TestWaveformSource::GenerateStep	(	float	vlo,
		float	vhi,
		int64_t	sampleperiod,
		size_t	depth
	)

Generates a step waveform.

The waveform starts at vlo for half of the total duration, the instantly transitions to vhi and remains at vhi for the remainder of the total length.

Parameters

vlo	Starting voltage
vhi	Ending voltage
sampleperiod	Interval, in femtoseconds, between samples
depth	Number of points in the waveform

InterpolateSparameters()

void TestWaveformSource::InterpolateSparameters ( float  bin_hz, size_t  nouts  )

protected

Recalculate the cached S-parameters used for channel emulation.

Parameters

bin_hz	Size of each FFT bin, in Hz
nouts	Number of FFT bins

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The documentation for this class was generated from the following files:

• lib/scopehal/TestWaveformSource.h
• lib/scopehal/TestWaveformSource.cpp