The Model 608A Signal Generator is a general purpose laboratory generator covering the 10 to 500 megacycle band. Both the frequency and output are calibrated. Internal modulation at either of two fixed frequencies is provided. The instrument may also be modulated from external sources of sine waves or pulses. The Model 608A may be used for measuring gains selectivity or image rejection of receivers, IF and broad band amplifiers. The high output voltage (1 volt into a 50 ohms load) of the generator is suitable for driving bridges, slotted lines, transmission lines, antennas, and filter networks.