The Astronics/EADS/Racal 2461-Ce is a high-performance 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.
