General Radio Corp 1390-B Random Noise Generator. Generates random noise (vacuum tube source) into a 600 ohm load (0.00005-5VRMS, metered and in decade ranges). Upper frequency bandwidth (at 3dB point) can be set to 20KHz, 500KHz, or 5MHz. Ideal for random vibration testing, and audio/noise filtering tests.
Broad band noise signal: 5Hz to 5MHz uniform spectrum level. Useful in noise and vibration testing of mechanical and electrical systems. Upper frequency cutoff can be set at: 20kHz, 500kHz, or 5MHz. Output level is controlled by a 4-step attenuator with 20 dB steps. Continuously variable control providing a calibrated, metered output from <30