The TDDS100-48 from Telemakus is a USB-stick-sized direct digital synthesized RF signal source that operates from 1 Hz to 100 MHz. It has a 0 dBm output and can be swept in steps as low as 1 Hz between any two frequencies in its specified range. It has a phase noise of -140 dBc at 100 kHz and second and third harmonics under -60 dBc at 10 MHz. The USB-controlled source has a 0.5 GB of flash memory which stores its installation files, test data and supporting documentation. It is available with SMA female connectors.