Pulse Jitter Measurement 2 - Kenwood CS-1100 Instruction Manual

3. Remove the reference signal and input the unknown
signal, adjusting the SWEEP TIME/DIV control for easy
observation.
Measure the width of one cycle in divisions and use the
following relationship to calculate the actual period.
Using the formula:
Period of unknown signal = Width of 1 cycle (div) x sweep
coefficient x SWEEP TIME/DIV setting
Reference signal
H B S S 1 1
Fig. 25
Fig. 26
[EXAMPLE]
SWEEP TIME/DIV is 0.1 ms and apply 1.75 kHz reference
signal. Adjust the A VARIABLE so that the distance of one
cycle is 5 divisions.
Substituting the given value:
Horizontal coefficient =
Then, SWEEP TIME/DIV is 0.2 ms and horizontal amplitude
is 7 divisions. (See Fig. 26)
Substituting the given value:
Pulse width = 7 (div) x 1 . 1 4 2 x 0 . 2 (ms) = 1.6 ms
24
Unknown
signal
1 -75 (kHz) = 1.142
5 x 0 . 1 (ms)
PULSE JITTER MEASUREMENT
1. Apply the signal to the INPUT jack and set the vertical
MODE to the channel to be used.
Use the VOLTS/DIV to adjust for an easy to observe
waveform display. Special care should be taken to ad-
just the trigger group of controls for a stable display.
Set the A VARIABLE to C A L position.
2. Select the HORIZ DISPLAY to A L T and pull out the
SLOPE switch to affect the S T A R T S AFTER DELAY
mode.
Adjust T T R A C E SEP control and the DELAY TIME
MULT control for intensified display of the waveform to
be measured.
3. Using the B SWEEP TIME/DIV adjust the display for in-
tensification of the entire jitter area of the waveform.
4. Select the HORIZ DISPLAY to B DLY'D.
Measure the width of the jitter area.
The jitter time is this width in division multiplied by the
setting of the B SWEEP TIME/DIV control.
Using the formula:
Pulse jitter = Jitter width (div) x B SWEEP TIME/DIV setting
[EXAMPLE]
The example shows a case in which the jitter width was
measured at 1.6 divisions wide with the
TIME/DIV set at 0.2 /ts. (See Fig. 27)
Substituting the given value:
Pulse jitter = 1 . 6 (div) x 0.2 (jts) = 0.32 /*s
SWEEP MULTIPLICATION (MAGNIFICATION)
The apparent magnification of the delayed sweep is deter-
mined by the values set by the A and B SWEEP TIME/DIV
controls.
1. Apply a signal to the INPUT jack and set the vertical
MODE to the channel to be used, adjusting VOLTS/DIV
for an easily observed display of the waveform and the
other controls if necessary.
B SWEEP
Pulse jitter
Fig. 27