Reference Bit Waveform Creation VI

Owning Palette: Clock Recovery VIs

Requires: Jitter Analysis Toolkit

Creates an ideal reference data waveform that is synchronized to the source waveform by using the reference crossing times to locate when the data bit changes state.

Example

Reference Bit Waveform Creation (DBL)

This instance operates on the waveform data type when the Y data values are double-precision, floating-point numeric values. Use the I8 instance of this VI with integer data to reduce the size of the data and the memory usage.

	waveform is the waveform to measure. t0 specifies the start time of the waveform. dt specifies the time interval in seconds between data points in the waveform. Y specifies the data values of the waveform.
	ref level crossings specifies information about the locations of level crossings in the reference clock waveform. You can use the Clock Recovery VIs to generate this cluster from a measured waveform. t0 specifies the time at which the first sample occurs in the clock signal. dt specifies the time interval in seconds between the individual samples in the clock signal. indexes contains the index numbers of the samples in the clock signal with values that fall at the crossing level. slope identifies the direction of the first transition in the waveform. -1 Falling Edge—Specifies the transition is a falling edge, or one with a negative slope. 1 Rising Edge (default)—Specifies the transition is a rising edge, or one with a positive slope. crossing level specifies the value of the clock signal at each of the samples in indexes.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	waveform dup returns waveform unchanged.
	ideal bit waveform returns a representation of the waveform that has voltage values replaced with bits that indicate whether the waveform is in its high or low state at unit intervals. t0 returns the time at which the first sample occurred in the original waveform. dt returns the time interval in seconds between the individual samples in the original waveform. Y is a sequence of zeros and ones that represent whether the waveform is at its low or high state, respectively, at each unit interval.
	error out contains error information. This output provides standard error out functionality.

Reference Bit Waveform Creation (I8)

This instance operates on the waveform data type when the Y data values are 8-bit signed integers.

	waveform is the waveform to measure. t0 specifies the start time of the waveform. dt specifies the time interval in seconds between data points in the waveform. Y specifies the data values of the waveform.
	ref level crossings specifies information about the locations of level crossings in the reference clock waveform. You can use the Clock Recovery VIs to generate this cluster from a measured waveform. t0 specifies the time at which the first sample occurs in the clock signal. dt specifies the time interval in seconds between the individual samples in the clock signal. indexes contains the index numbers of the samples in the clock signal with values that fall at the crossing level. slope identifies the direction of the first transition in the waveform. -1 Falling Edge—Specifies the transition is a falling edge, or one with a negative slope. 1 Rising Edge (default)—Specifies the transition is a rising edge, or one with a positive slope. crossing level specifies the value of the clock signal at each of the samples in indexes.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	waveform dup returns waveform unchanged.
	ideal bit waveform returns a representation of the waveform that has voltage values replaced with bits that indicate whether the waveform is in its high or low state at unit intervals. t0 returns the time at which the first sample occurred in the original waveform. dt returns the time interval in seconds between the individual samples in the original waveform. Y is a sequence of zeros and ones that represent whether the waveform is at its low or high state, respectively, at each unit interval.
	error out contains error information. This output provides standard error out functionality.

Example

Refer to the ISI Jitter Measurement VI in the labview\examples\Jitter Analysis\Jitter Measurements directory for an example of using the Reference Bit Waveform Creation VI.