YOKOGAWA TA120E, User Manual

Page: 53 / 165

4-14
IM 704420-01E
4.7 Switching the Clock Signal (Applicable to D-to-
C Jitter Measurements)
«For a functional description, see section 1.4.»
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
Procedure
When the measurement function is set to [DtoC DVD] (D-to-C jitter), you can use the
regenerated clock signal.
Using the regenerated clock signal
Press the SHIFT+CLOCK (PLL) key. The PLL indicator lights and the PLL circuit
turns ON. The D-to-C jitter measurements can now be carried out using the
regenerated clock signal.
Using the clock signal that is applied to the clock input connector
Press the SHIFT+CLOCK (PLL) key while the PLL circuit is ON. The PLL indicator
turns OFF, and the PLL circuit turns OFF. The D-to-C jitter measurements can now
be carried out using the clock signal that is applied to the clock input connector.
Explanation
For the clock signal used to measure the D-to-C jitter, you can select either the clock
signal that is applied to the clock input connector or the clock signal that is regenerated
by the PLL circuit. To use the clock signal regenerated by the PLL circuit, you must turn
ON the PLL circuit operation according to the steps above. When the PLL circuit
operation is turned ON, the settings made in “Selecting the slope of the clock signal” in
section 4.1 are made invalid, and the rising slope is always used.
Note
• The clock signal regenerated by the PLL circuit is regenerated from the single-speed data
signal of a DVD. Therefore, the frequency range of the regenerated clock signal is 27
MHz
±
10%.
• If the clock cannot be regenerated using the PLL circuit (PLL unlock), the PLL indicator blinks,
the meter needle goes off the scales beyond the scale line that indicates the maximum value
of each scale, and the characters “unLoC” appear on the display. In addition, the DC output
(see section 7.1) is set to 5 V.