Based on a custom ultra-high-repetition-rate GaN differential pulser IC, the palm-sized Ultracomb-8G is powered from any USB3.0/3.1 port through which the user can program comb amplitude, comb picket spacing and low/high-frequency spectral weighting. Comb picket spacing can be software-programmed to any frequency from 10MHz to 2GHz in single-ended-output mode (10-50MHz in differential output mode) in 0.01 Hz steps, generated by an on-board LMX2594 synthesizer driven from an internal 150fs-jitter reference clock or external 10-500MHz reference. The unit can also be programmed in 1:1 clock mode, enabling the pulse repetition rate of the comb generator (and the comb tooth spacing) to be the same as the external reference/clock input. Its differential outputs enable direct antenna connections without the use of a BALUN, and 3dB higher total output level. All models include Windows 10 and RedHat Linux 7.6 and Centos Linux 7.6 drivers and user programs with full source, as well as a comprehensive QT control panel

• Fully Differential Pulse Outputs with amplitude up to 20V into two 50 ohm loads or 100 ohm differential load, or two opposing single-ended 10V pulses.
• 65ps to 400ps programmable rise time and 140ps to 800ps FWHM pulse widths
• 10 MPPS to 2 GPPS programmable pulse rate in single-ended mode. 10 MPPS to 50 MPPS in differential mode. Pulse shape independent of rate
• Internal reference (150fs RMS jitter) or external reference/clock, SW selectable.
• Ultra-low jitter internal LMX2594 synthesizer allows virtually any pulse rate with sub- Hertz resolution, and precise synchronization, including 1:1 clocking, with external reference/clock, with programmable external clock to pulse delay.
• Concurrent low-jitter square wave sync/trigger output in sync with pulse outputs.
• USB 3.0/3.1 Interface. No external power required. 5.5" L x 2" W x 0.6" D
• Powerful QT software interface and cross-platform C libraries
• Generates ultra-low phase noise combs to 10GHz in single-ended mode.

• Pulse leading edge rise time (10-90%): 65ps to 400ps programmable
• Picket spacing (Pulse rate): Single-ended mode: 10 Mhz to 2 Ghz
• Picket spacing (Pulse rate): Differential mode: 10 MHz to 50 MHz
• Differential Phase Matching (10-50Mhz): 20 ps max
• Differential Amplitude Matching (10-50Mhz): 2% typ, 5% max
• Output Amplitude Range (each output into 50 ohms, diff=twice this value):
• 100-400ps rise time setting: 2V to 10V peak (6-20V diff)
• 65-100ps rise time setting: 1.5V to 7V peak (6-14V diff)
• Pulse jitter, cycle-to-cycle, both + and - outputs: Internal Ref, Fpulse= 50 MPPS <1ps RMS