The 5257A Transfer Oscillator Plug-In is designed to be used in the 524X-Series Counter Mainframes. The frequency range is from 50MHz to 18GHz and accepts CW, Pulsed, RF or FM modulated signals. Sensitivity is rated at -7 dBm (50MHz to 15GHz) and -4 dBm (15GHz to 18GHz). APC Lock range is approximately ?0.2% of input frequency. Pulse carrier frequency measurements; minimum pulse width, 0.5 ?s; minimum repetition rate, 10 pulses/sec. Input impedance is 50-ohms and VFO stability is typically 1x10E-07 per minute (after 2 hours).