VSC8113QB1 VITESSE [Vitesse Semiconductor Corporation], VSC8113QB1 Datasheet - Page 8

• Manufacturer Part Number: VSC8113QB1
• Description: ATM/SONET/SDH 622 Mb/s Transceiver Mux/Demux with Integrated Clock Generation and Clock Recovery
• Manufacturer: VITESSE [Vitesse Semiconductor Corporation]

ATM/SONET/SDH 622 Mb/s Transceiver Mux/Demux
with Integrated Clock Generation and Clock Recovery
Page 8
Clock Recovery
Loop Filter and a Voltage Controlled Oscillator (VCO). The phase detector compares the phase information of
the incoming data with the recovered clock. The frequency detector compares the frequency component of the
data input with the recovered clock to provide the pull in energy during lock acquisition. The LoopFilter inte-
grates the phase information from the phase and frequency detectors and provides the control voltage to the
VCO.
ered clock are different, a data bit in the serial data stream will occasionally be dropped. If the Frequency Detec-
tor does not detect this condition in a moving 1.5 s window, the CRULOCKDET output is asserted to signal
that the CRU is frequency locked to the serial data stream. This output is forced low if it detects that a data bit is
dropped or if the recovered clock frequency drifts more than 5% from the CMU’s output frequency.
The fully monolithic Clock Recovery Unit (CRU) consists of a Phase Detector, a Frequency Detector, a
The CRU provides a lock detect function. If the frequencies of the serial data stream and the CRU’s recov-
741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: [phone]
VITESSE
Figure 6: External Integrator Capacitor
VITESSE SEMICONDUCTOR CORPORATION
SEMICONDUCTOR CORPORATION
+
CP1
CN1
-
CP = 0.1 F
CN = 0.1 F
CN2
CP2
VSC8113
Data Sheet
G52154-0, Rev 4.2
3/19/99