Teledyne LeCroy WavePro Automation Command User Manual

Page 226

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Automation Command and Query Reference Manual - Control Reference

PLLFrequency

Double

From 2488 to 2.488e+008 step 1

Range

This setting controls the bandwidth of a single-pole PLL emulation that can be selectd as PLL Type
"FC Golden". This bandwidth is usuall controlled by app.SDA2.CDR.CutOffDivisor, and the resulting
bandwidth can then be read from this control variable. When app.SDA2.CDR.PLLFrequency is set,
the CutOffDivisor is set based on this value and on the current SignalFrequency. Please see
CutOffDivisor for further explanation.

Description

PLLType

Enum

Sets the type of our software PLL emulation. Within SDA2 user interface other types besides those
shown below may be listed, if so they are mapped onto Custom, they select Custom PLL with
appropriate settings.

Description

Values

Custom

1 pole (and 1 parasitic 0) or 2 pole PLL, with customizable settings

DVI

Reuses the Custom 1 pole, pole at 4MHz, zero at 70MHz (that is, negligible).

FBDIMM

Two 2 pole PLLs separated by a Tranport Delay, preset to values needed for FB-DIMM.

GOLDEN

1 pole PLL, when CutOffDivisor is at its default value of 1667 this it the Fibre Channel golden PLL

PCIEXPRESS

PCI-Express Gen 1 preset. SDA2 adds three PCIe Gen2 PLLs, as specified in the PCIE CEM spec.

RefClkSlope

Enum

When UseRefClk is set to ON, then this control specifies which edges of the reference clock signal
should be used to sample the data signal.

Description

Values

Both

Use both edges - half frequency clock

Neg

Use negative going edges

Pos

Use positive going edges

SignalFrequency

Double

From 90000 to 4e+010 step 1

Range

if UseRefClk is OFF, then SignalFrequency is the BaseFrequency, which is derived from the data
signal by FindBaseFrequency. If UseRefClk is ON, then SignalFrequency is BaseFrequency
multiplied by ClockMultiplier; BaseFrequency is derived from the reference clock signal by
FindBaseFrequency.

Description

UsePLL

Bool

The expected use of SDA2 is with UsePLL set to true. In that state, the SDA2 uses the selected PLL
type to produce a clock signal that tracks variations in the data rate. Variations at frequencies low
enough for the PLL to track effectively are not counted as jitter. If the data is produced using a very
stable clock, it is possible to set UsePLL to false, in which case the SignalFrequency is uses as a
perfectly stable (mathematically generated) reference; in this state any variation even at very low
frequencies will be seen in jitter measurements.

Description

1-212

918501 RevA

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