The Standard Signal Generator 931 H is designed for repairs, production testing and design work on radio receivers and similar apparatus, operating in the range 50 kc/s to 50 Mc/s, 1.2. Frequency is accurately set by the direct reading dial and a 1000 point per scale vernier gives the possibility of returning precisely to a previously noted frequency. 1.3. The RF circuit is designed for low drift and low harmonic content end output is practically constant throughout any given range. A strong detent mechanism gives exact positioning of the coil turret. 1.4* Output, adjustable from a few tenths of a microvolt to one volt on RF, ten times as much on AF, is monitored permanently by a moving coil meter. 1.5. Output may be unmodulated RF, modulated RF (internal or external), AF, or multivibrator. All outputs may be used with the attenuator. RF level, modulation depth, and AF level are all monitored. 1.G, The attenuator consists of a non inductive potentiometer feeding a ladder network. Output impedance is near 75 Ω except for 100 nV output lovol (0 to 40 Ω). 1.7» A standby Switch is provided that cuts all RF and AF outputs whilst leaving the heaters on and dissipating the same total heat as on normal output.