The Model 1940A is a four channel 400 MHz DDS signal generator in a rackmount (1U) instrument case. The 1940A generates up to four different output frequencies simultaneously from 200 kHz to 400 MHz in 1 Hz steps. The 1940A can be locked to an external frequency standard or used stand-alone with its internal temperature compensated crystal oscillator (TCXO). Sine waves with up to 60 dB of attenuation are standard. The 1940A can be configured with 2 or 4 (standard) frequencies. Simple front panel control or RS232 allows setting of all parameters, which can be saved into non-volatile EEPROM memory upon power down.