The MK2059-01 is a VCXO (Voltage Controlled Crystal Oscillator) based clock generator that produces common telecommunications reference frequencies. The output clock is phase locked to an 8kHz (frame rate) input reference clock. The MK2059-01 also provides jitter attenuation. Included in the selection of output frequencies are these common system clocks: 1.544 MHz (T1) 2.048 (E1) 19.44 MHz (OC-3) 16.384 MHz (8x E1) This monolithic IC, combined with an external inexpensive quartz crystal, can be used to replace a more costly hybrid VCXO retiming module. Through selection of external loop filter components, the PLL loop bandwidth and damping factor can be tailored to meet input clock jitter attenuation requirements. A loop bandwidth down to the Hz range is possible