Astronics / EADS / Racal 2461-Ce Universal Counter Timer VXI Card

The Astronics/EADS/Racal 2461-Ce is a universal counter timer for precision timing and frequency measurements in VXI-based test systems. This C-size VXI module delivers frequency measurement to 200 MHz with 9-digit resolution, time interval measurement at 1 ns single-shot or 100 ps average mode, and comprehensive pulse characterization including rise time, fall time, pulse width, and duty cycle. The 2461-Ce integrates a Temperature Compensated Crystal Oscillator (TCXO) for enhanced timebase stability, supporting external 10 MHz inputs at 100 mV minimum. Nine arming modes and programmable trigger levels from -5.1 V to +5.1 V (x1 range) enable flexible signal conditioning across ±5.1 V or ±42 V input ranges. Phase measurement, totalize functions (manual, by pulse, by cycle, and timed), and DVM capabilities for MAX, MIN, and DC voltage measurement round out the feature set.

Technical Specifications

Form Factor: C-size VXI module

Frequency Measurement Range: Up to 200 MHz

Frequency Resolution: Up to 9 digits per second

Time Interval Resolution: 1 ns single-shot; 100 ps average mode

Input Voltage Range: ±5.1 V or ±42 V

Trigger Level Range: -5.1 V to +5.1 V (x1, 2.5 mV resolution); -51 V to +51 V (x10, 25 mV resolution); -200 V to +200 V (x40, 100 mV resolution)

Minimum Signal Amplitude (x1 Attenuation): <50 MHz: 5 V pk-pk; <100 MHz: 2.5 V pk-pk; <200 MHz: 1.5 V pk-pk

Minimum Signal Amplitude (x10 Attenuation): <50 MHz: 50 V pk-pk; <100 MHz: 25 V pk-pk; <200 MHz: 15 V pk-pk

Timebase: Internal TCXO; external 10 MHz input at 100 mV minimum, 1 kΩ impedance

Arming Modes: 9 selectable modes

Key Features

Pulse rise time, fall time, pulse width, and duty cycle measurement

Phase measurement capability

Multiple totalize functions: manual, by pulse, by cycle, and timed

Digital voltmeter with MAX, MIN, and DC voltage measurement

Programmable measurement timeout

Accommodates up to 3 function cards in single module (positions 1 and 2 with front panel access)

Typical Applications Aerospace, defense, and telecommunications test environments requiring integrated frequency, timing, and pulse characterization.

Compatibility & Integration Part of the 2460 Series family, compatible with VXI-based modular test systems.