“This series utilizes a reciprocal counting technique to provide high resolution at all frequencies, from 1mHz to 3GHz for the 1823B, or 6GHz for the 1826B,” said the company. “The counters deliver eight significant digits in 1s of measurement time, nine digits in 10s and 10 digits in 100s.”
Input A works from dc to 125MHz and offers ac or dc coupling, 1MΩ or 50Ω impedance, 1:1 or 5:1 attenuation and a variable threshold.
Input B has 50Ω impedance and works across 80MHz to 3GHz.
Input C, fitted only to the 1826B (see photo), has a 50 Ω N-type connector for operation between 2 and 6GHz.
A well as frequency, they will measure period (input A or B), ratio (input B:A) or pulse width (input A), and will count events (input A).
The display has ~13mm characters, and control it through the front panel or from a computer through USB – which can also be used to power the instrument.
AC power is also possible and there is an internal battery (x3 2.5Ah NiMH cell) is said to support 24 hours of operation. Only the ac adapter can recharge the battery (four hours), not the USB input.
Dimensions are 260 x 88 x 235mm and 950g, plus 170g for the ac adapter.