Model PLXO-250 is a phase-locked crystal oscillator (PLXO) from EM Research that provides a stable 250-MHz output signal when fed with a 10-MHz reference source. The oscillator, which measures just 1.5 x 1.5 x 0.6 in. and delivers +7 dBm output power, achieves phase noise of better than -95 dBc/Hz offset 100 Hz from the carrier and better than -140 dBc/Hz offset 10 kHz from the carrier. Harmonics are less than -50 dBc while subharmonics are less than -70 dBc. The oscillator works with a +12-VDC supply.