Fluke PM6680B High Resolution Timer/Counter Programmable

The Fluke PM6680B is a high-resolution timer/counter with programmable automation for precision frequency, time interval, and timing measurements across laboratory, research, and manufacturing environments. It delivers 10-digit frequency resolution in 1 s measuring time and sub-nanosecond time interval accuracy, with full SCPI command compliance and IEEE-488 bus control supporting up to 125 triggered measurements per second.

Technical Specifications Frequency Measurement

Input A: DC to 225 MHz (AC-coupled 10 Hz to 225 MHz); 4.2 GHz with optional module

Input B: DC to 100 MHz

Input C: Up to 4.2 GHz (optional)

Resolution: 10 digits in 1 s measuring time Time Interval & Pulse Measurements

Single-shot resolution: 250 ps

Averaged resolution: 100 ps

Range: 0 ns to 10^10 s

Rise/fall time: 3 ns to 10^10 s (up to 160 MHz)

Pulse width: 3 ns to 10^10 s (up to 160 MHz)

Period: 6 ns to 10^10 s Additional Measurements

Duty factor: 0 to 1 (0.11 Hz to 160 MHz)

Phase (A relative B): −180° to +360° with 0.01° resolution (0.03 Hz to 160 MHz)

Ratio (A/B, C/B): 10^−9 to 10^15

Totalization: 0 to 10^17 (8 modes including simultaneous up/down counting)

Frequency burst: Measures burst frequency and PRF with selectable start delay

Peak reading voltmeter: 4-digit, 120 MHz Signal Conditioning

Input impedance: 1 MΩ || 15 pF

Sensitivity: 50 mVrms to 5 Vrms; 20 mV < 100 MHz on Channel C

Input coupling: AC/DC selectable

Trigger level: ±5 V Timebase & Stability

Standard timebase with optional TCXO, high-stability oven, and very high-stability oven modules

Time base stability: <5 × 10^−11 per month (with oven options)

Key Features

Programmable all front-panel functions; macro programming for user-defined mnemonics

Internal memory: Up to 2,600 readings with internal transfer rate to 2,000 measurements/s

Arming input with inhibit capability; preset time or trigger event delay

IEEE-488 bus compliance with SH1, AH1, T6, L4, SR1, RL1, DC1, DT1, E2 interface functions

SCPI command set compliant

Typical Applications Frequency and period measurements on digital and RF signals; timing analysis in prototype validation; automated test sequences in production environments; burst signal characterization; duty cycle and phase relationship analysis.

Compatibility & Integration Full IEEE-488 programmability enables system integration with automated test systems. SCPI compliance ensures compatibility with standard software frameworks. Internal memory supports standalone logging without external controllers.