YOKOGAWA TA120E, User Manual

Page: 55 / 165

5-1
IM 704420-01E
Displaying the Measured Results
5
5.1 Using the Analog Meter
«For a functional description, see section 1.5.»
Keys
KEY
LOCK
MEAS
SET AVE /T
0
2
4
4
8
6
12
8
16
10
%
deg
%
20
180
us
ms ns
MEAS
x1
3TCD
xN
3TCD
xN
BI-PHASE
SPEED DELAY GATE TIME
FUNC GATE
LOCAL
DATA
SCALE
PRESET
PHASE
10 20
TRIG CLOCK PHASE
AUTO MAN
GP-IB
REMOTE
EQLZ LEVEL PLL
SHIFT
ARM INH
DtoC
DVD
0.1s
0.5s
MAN
UTILITY OPTION
10
5
σ σ
Lights when measured results are shown on the display.
Procedure
Indicating the jitter ratio on the analog meter
When the TA120E is turned ON, the meter needle indicates the measured jitter ratio.
Selecting the scale
Press the SCALE key to select [10%] or [20%]. The needle moves according to the
selected scale.
Explanation
Jitter ratio indication on the meter
The TA120E continuously makes measurements when the power is turned ON. The
meter needle indicates the jitter ratio (
σ
/T) of the measurement function that was
selected in section 4.1.
* 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 speed 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.
Selecting the scale
You can select the scale that is used when indicating the measured jitter ratio on the
analog meter.
• 10%
The scale line is written every 0.2%. The needle is capable of indicating a jitter
ratio of up to 11%.
• 20%
The scale line is written every 0.5%. The needle is capable of indicating a jitter
ratio of up to 22%.
Note
• The phase difference between the data signal and the clock signal can be indicated on the
analog meter in the range from 0 deg to 360 deg. The scale line is written every 90 degrees.
For a description on how to use the analog meter when it is indicating the phase difference,
see section 4.8.
• The minimum interval for measuring jitter on the TA120E is 50 ms. In some cases, the
analog meter may not be able to keep up with the changes in the measured value.
• If the jitter ratio exceeds the maximum value of each scale, the meter needle goes off the
scale beyond the scale line that indicates the maximum value of each scale.
• If the trigger is not activated on the input signal and measurements cannot be made, the meter
needle goes off the scale beyond the scale line that indicates the maximum value of each scale.
• 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 meter needle
goes off the scale beyond the scale line that indicates the maximum value of each scale. In
addition, the DC output (see section 7.1) is set to 5 V.
Chapter 5 Displaying the Measured Results