Anritsu BERTWave MP2100B, Operation Manual, Page: 212 / 382

Chapter 7 Measuring Waveform
7-26
7.6.1 Setting Clock Recovery Unit
The Option 053, 054, or 055 Clock Recover Unit (CRU) can generate a
clock from the signal collecting data.
The waveform can be measured using the generated clock.
The following can be set using the clock recovery unit.
●
Clock Recovery
●
CRU Loop BW
CRU Input sets the input connector for the clock recovery unit.
Clock Recovery sets the output On/Off and frequency range.
CRU Loop BW is the loop filter bandwidth used at the frequency control
circuit for CRU.
Phase Comparator Input signal Loop filter
Voltage
Control Osc
Buffered Amp
CRU Out
CRU In
Figure 7.6.1-1 Block Diagram of Clock Recovery Unit
Although the frequency band is wide, instantaneous frequency
fluctuations can be buffered. The communications standards specify the
loop filter bandwidth used to measure jitter.
CAUTION
● The impedance of the CRU In and CRU Out connectors
is 50 Ω . Measurement may not be performed correctly if
a cable with another impedance is used or if the
impedance of the connected device is not 50

.
● The CRU Out connector output voltage is 0.5 to 1.5 Vp-p
between 8.5 GHz and 12.5 GHz, and 0.27 to 0.54 Vp-p for
2.7 GHz or lower. Check that the output voltage does
not exceed the connected device maximum input
specifications. If it does, connect an attenuator to the
CRU Out connector.