Micronetics' CNG-SatCom includes constant noise output. This feature allows the user to set and maintain a desired level of noise while varying the carrier signal. The internal power meter is used to measure the noise and carrier levels and to maintain accurate SNR that are set by the user. A Master/Slave attenuation design allows the modem to maintain a lock on the carrier signal while establishing new carrier to noise ratios. This instrument has dual impedance input/output capability that is easily selected from the front panel or through remote GPIB commands. The rear panel is configured with both 50 ohm SMA(F) connectors and 75 ohm BNC(F) connectors. The instrument is internally calibrated for either impedance, which eliminates the need for any external hardware and potential losses that will result from these conversions.