INTRODUCTION the carrier-frequency range from 5 kc to 50 Me. It may be amplitude-modulated up to 80% over the audio range from 20 c to 15 kc. The carrier output voltage at the attenuator jack is accurately adjustable to any value from 0.1 microvolt to 200 millivolts; output voltages up to two volts are available at a second jack. receivers. It can also be used as an r-f voltage standard in fi“ld-intensity measurements. Its wide carrier-frequency range makes it suitable for use as a power source in bridge measurements and for measurements on supersonic equipment.