Appendix A: Specifications
VX4101A MultiPaq Instrument User Manual A–13Table A–30: Counter Specifications Terms (Cont.)
Term Description
Timing Terms DJ Delay Jitter
P The period of the signal being measured (P = 1/F).
PVCO (1/ FVCO). Approximately 0.987 ns.
SlewESlew at the ending edge of a measurement. For sine waves, the slew rate at
the 50% level is as follows:
2 × π × F × VPP/2
For sine waves at 10% (or 90%) the slew rate is as follows:
cos (arcsine (–1.0 + (10% of 2.0))) × 2 × π × F× VPP/2
SlewSSlew at the starting edge of a measurement.
TBE Time Base Error of the 10 MHz root time base provided by the Slot 0 board, a
frequency plugged into the Slot 0 board, or the optional on-board oscillator.
TBEVCO Time Base Error of the root time base applied to the frequency of the Universal
Counter Voltage Controlled Oscillator time base.
TJE1Trigger Jitter Error of the Channel 1 event.
TJE2Trigger Jitter Error of the Channel 2 event.
NOTE: Detection of signals crossing prescribed thresholds is subject to timing uncertainty
(trigger jitter error) due to system noise and threshold inaccuracies. This error affects all
measurements but is more pronounced for single-shot measurements and for signals with
slow rise and fall time. The timing trigger jitter error (TJE) equals:
TLE1Trigger Level Error of the leading (first) event.
TLE2Trigger Level Error of the trailing (second) event.
TJE Trigger Jitter Error which is the input signal RMS noise voltage.
TJE1Trigger Jitter Error of the leading (first) event.
TJE2Trigger Jitter Error of the trailing (second) event.
[(RMSnoiseofinputsignal)2)(RMSnoiseofinputChannel)2]1ń2
InputSlewRateattheTriggerPoint
Mathematical Terms exp{} Exponentiates to the power given by the expression within the bracket.
Int() Converts the expression within the parenthesis to the nearest integer of lesser
or equal value. For example:
Int(1.7) = 1 and Int(-1.7) = -2
(Use floor (x) in the C programming language.)
log() Computes the base 10 (common) logarithm of the expression within the
parenthesis.