5-3
IM 704420-01E
Displaying the Measured Results
5
Explanation
Numeric display of jitter, jitter ratio and average value
The TA120E continuously makes measurements when the power is turned ON. The
jitter ratio (
σ
/T
*1
), jitter (
σ
), and average value
*2
of the measurement function that was
selected in section 4.1 is displayed using numeric values.
*1 T is the period of the clock signal of the CD or DVD. When the measurement function is
3T jitter, T = 231.385/N (where N is the
×
N value). When the measurement function is D-
to-C jitter, T is the period of the clock signal that is applied to the clock input connector or
regenerated by the PLL circuit.
*2 The average value is the average of the time measurement.
When the measurement function is set to 3T jitter: Average of the pulse width of the
measured 3T signal
When the measurement function is D-to-C jitter: Time difference average between the
data signal and clock signal
• When [
σ
] and [ns] light, the jitter is displayed using numeric values.
• When [
σ
/T] and [%] light, the jitter ratio is displayed using numeric values.
• When [AVE] and [ns] light, the average of the measured values is displayed using
numeric values.
Turning ON/OFF the numeric display
If the changes in the numeric display of the jitter or jitter ratio bother you, you can
display the characters “d-oFF” instead of displaying the values.
Note
•
Even when the numeric display is turned OFF, the display shows the setup values when
setting the TA120E. For the setup procedure, see chapter 4. Error codes and version
information are also shown on the display even when the numeric display is turned OFF.
•
If the value to be displayed using numeric values cannot be obtained, the display shows “- - -
- -” (bar).
•
If the PLL circuit is turned ON during D-to-C measurement and the clock cannot be
regenerated using the PLL circuit (PLL unlock), the PLL indicator blinks, and the characters
“unLoC” are shown on the display. In addition, the DC output (see section 7.1) is set to 5 V.
•
If numeric display is shown when the average coefficient (see section 7.1) or the jitter ratio
correction coefficient (see section 7.1) of the DC output filter is some value other than the
initial value, the [
σ
/T] (when displaying the jitter ratio) or [
σ
] (when displaying the jitter)
measurement indicator blinks.
•
If the average value is shown when the average coefficient (see section 7.1) of the DC output
filter is some value other than the initial value, the [AVE] measurement indicator blinks.
5.2 Displaying the Numeric Value and Turning OFF the Numeric Display
