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Clock Recovery by PLL Filter VI

LabVIEW 2012 Jitter Analysis Toolkit Help

Edition Date: June 2012

Part Number: 373270B-01

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Owning Palette: Clock Recovery VIs

Requires: Jitter Analysis Toolkit

Constructs a reference clock that is synchronous with the data in a signal by using a phase-locked loop (PLL) to lock the phase of an oscillator to the phase of the data edges. Wire data to the waveform input to determine the polymorphic instance to use or manually select the instance.

Use the pull-down menu to select an instance of this VI.

Clock Recovery by PLL Filter (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.

reset? specifies whether to clear the internal state of the PLL prior to starting operation. When reset? is TRUE, LabVIEW clears all state information and initializes the PLL with an initial phase of 0. When reset? is FALSE, as in a continuous operation, this VI uses the state information at the end of the previous iteration to initialize the PLL at the beginning of the current iteration.
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.
loop filter (forward) specifies the forward coefficients of the IIR loop filter. The default is (1.05, –0.95).
loop filter (reverse) specifies the reverse coefficients of the IIR loop filter. The default is (1, –1).
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
VCO carrier freq (Hz) specifies the reference carrier frequency used by the voltage-controlled oscillator (VCO) to track the carrier phase of the input signal. The default is 0 Hz.
PLL waveform returns the waveform representation of the clock signal.
t0 returns the start time of the waveform.
dt returns the time interval in seconds between data points in the waveform.
Y returns the data values of the waveform.
ref level crossings returns information about the locations of level crossings in the reference clock waveform.
t0 returns the time at which the first sample occurred in the clock signal.
dt returns the time interval in seconds between the individual samples in the clock signal.
indexes returns the index numbers of samples in the clock signal that fall on the crossing level.
slope returns whether the direction of the first transition in the waveform is rising or falling

-1Falling Edge—The transition is a falling edge, or one with a negative slope.
1Rising Edge—The transition is a rising edge, or one with a positive slope.
crossing level returns the crossing level value at which the clock signal falls at each sample in indexes.
error out contains error information. This output provides standard error out functionality.

Clock Recovery by PLL Filter (I8)

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

reset? specifies whether to clear the internal state of the PLL prior to starting operation. When reset? is TRUE, LabVIEW clears all state information and initializes the PLL with an initial phase of 0. When reset? is FALSE, as in a continuous operation, this VI uses the state information at the end of the previous iteration to initialize the PLL at the beginning of the current iteration.
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.
loop filter (forward) specifies the forward coefficients of the IIR loop filter. The default is (1.05, –0.95).
loop filter (reverse) specifies the reverse coefficients of the IIR loop filter. The default is (1, –1).
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
VCO carrier freq (Hz) specifies the reference carrier frequency used by the voltage-controlled oscillator (VCO) to track the carrier phase of the input signal. The default is 0 Hz.
PLL waveform returns the waveform representation of the clock signal.
t0 returns the start time of the waveform.
dt returns the time interval in seconds between data points in the waveform.
Y returns the data values of the waveform.
ref level crossings returns information about the locations of level crossings in the reference clock waveform.
t0 returns the time at which the first sample occurred in the clock signal.
dt returns the time interval in seconds between the individual samples in the clock signal.
indexes returns the index numbers of samples in the clock signal that fall on the crossing level.
slope returns whether the direction of the first transition in the waveform is rising or falling

-1Falling Edge—The transition is a falling edge, or one with a negative slope.
1Rising Edge—The transition is a rising edge, or one with a positive slope.
crossing level returns the crossing level value at which the clock signal falls at each sample in indexes.
error out contains error information. This output provides standard error out functionality.

 

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