STC-50375300-15-C1 is an extended V-Band Down-Converter that converts millimeterwave signal from the frequency range of 50 to 75 GHz to the baseband at 5 to 30 GHz. The down-converter is designed and manufactured for Keysight PNA-X frequency extension so that the noise figure measurement can be preformed in the mmW frequency band. The down-converter has a built-in phase locked oscillator (PLO), which is externally referenced at 10 MHz. The down-converter also integrated a PIN diode based SPDT switch at the RF input for receiving signal level monitoring. The switch is controlled by TTL signal and the bypassing “ON” is at TTL “LOW”. The bypassing loss is 4 dB typical and 6 dB maximum. The RF ports for the down-converter are WR-15 waveguides with UG-385/U anti-cocking flange. The IF ouput is a 2.92 mm (F) connector and PLO reference signal input connnector is an SMA (F) connnector. A wall mount AC adapter is included for AC powering.