The M2020/21 is a Voltage Controlled SAW Oscillator (VCSO) based clock jitter attenuator PLL designed for clock jitter attenuation and frequency translation. The device is ideal for generating the transmit reference clock for optical network systems supporting 2.5GB to 10GB data rates. It can serve to jitter attenuate a stratum reference clock or a recovered clock in loop timing mode. The M2020/21 module includes a proprietary Surface Acoustic Wave (SAW) delay line as part of the VCSO. This results in a high-frequency, high-Q, low phase noise oscillator that assures low intrinsic output jitter.