HP/Agilent 5328B Universal Frequency Counter Description:
The 5328B Universal Counter provides solid performance for bench or system use. The unit offers sensitivity of 25 mV rms to 40 MHz, 50 mV rms from 49 to 100MHz. 9-digit LED display. Programmable with functions, resolution, sample rate, (maximum or manual control), arming, display modes, measurement modes, output mode, and reset commands. Trigger level, trigger slope, input impedance, coupling, separate/common/check, invert A and B are also programmable. Trigger level is programmable in 10 mV steps in x1; 100 mV in x10. 

HP/Agilent 5328B Universal Frequency Counter Specifications:

• Frequency measurements to 100 MHz 
• 10 ns Time Interval resolution, 10 ps with averaging
• 10 ns Period resolution, 1 fs with averaging. 
• HP-IB programming and External Arming Standard