The 1820B Series Universal Frequency Counters are compact instruments designed for versatile frequency measurements. They’re equipped with a high-quality temperature-compensated internal frequency reference to provide exceptional stability and accuracy, with a low aging rate of ±1 ppm across the entire temperature range. 
Featured on the front is a 0.5 in LCD for displaying frequency, period, ratio, pulse width, or event count measurements. Multiple input channels allow for precise measurements across a broad range of frequencies. Input A offers flexible signal conditioning, with configurable coupling (AC or DC), input impedance (1 MΩ or 50 Ω), attenuation (1:1 or 5:1), threshold (fully variable) and active edge. With the 1826B, an additional input C offers an N-type connector with 50 Ω input impedance and frequency range of 2 GHz to 6 GHz.

• 3 GHz (1823B) and 6 GHz (1826B) models
• Dedicated microwave channel with N-type connector (1826B only)
• 10-digit display resolution with 0.5 in LCD
• ±1 ppm time base stability
• Internal rechargeable batteries allow for up 24 hours of operating life
• Frequency ratio measurement function
• Time interval measurement
• Remote control with USB (VCOM) interface
• Selectable measurement time, 100 s, 10 s, 1 s, and 0.3 s