Novatech Instruments’ Model 409B/02 four-output, two-frequency 171 MHz direct digital synthesizer (DDS) table top signal generator offers 0.1 Hz frequency resolution and ±1.5 ppm accuracy. The unit features two phase synchronous sine wave outputs up to 171 MHz, with matching LVCMOS outputs, serial control, 500 MHz external clock input, and on-board TCXO (temperature compensated crystal oscillator), stable to ±1.5 ppm: all in a small table-top shielded instrument case. Based on Analog Devices’ AD9958, the 409B/02 has 32-bits of frequency resolution, 10-bits of amplitude resolution, and 14-bits of phase resolution on each of the channels. The small table top case allows the 409B/02 to be integrated into test stations and other applications requiring multiple and frequency agile outputs. When used with the external clock input, all 409B/02 units can be synchronized to a system-wide frequency standard. The serial control with simple text commands features non-volatile storage of all settings. Menu driven control software (SOF8) is included.