The Astronics/EADS/Racal 2201 is a dual-channel universal counter/timer engineered for precision frequency, period, pulse width, and time interval measurements in R&D and automatic test equipment environments. It delivers nine automated measurement functions with frequencies up to 225 MHz on main channels and an optional third input extending to 1.3 GHz. Averaged time interval resolution reaches 10 picoseconds, while trigger control offers 10 mV resolution across a ±5.1 V range (±51 V in X10 mode).
## Technical Specifications
**Measurement Functions**
• Frequency, Period, Time Interval, Time Interval Delay, Pulse Width, Frequency Ratio (Channel A to B), Totalize, Phase, Peak Signal Voltage
**Frequency Measurement**
• Main Channels A & B: DC to 225 MHz (DC coupling); 1 MHz to 225 MHz (AC coupling, 50 Ω)
• Optional Channel C (Option 41): 50 MHz to 1.3 GHz
• Resolution: Up to 9 digits per second
• Gate Time: 100 µs to 10 seconds (programmable internal); expandable to 1000 seconds external
• Measurement Technique: Reciprocal method to 10 MHz; conventional above 10 MHz
**Time Interval Measurement**
• Averaged Resolution: 10 picoseconds
• Single-Shot Resolution: 1 ns
• Delay Range: 100 µs to 1000 seconds
**Input Characteristics**
• Impedance: 50 Ω or 1 MΩ (Channels A & B); 50 Ω nominal (Channel C)
• Sensitivity (Sine, <225 MHz): <50 mVrms
• Sensitivity (Pulse, 5 ns width): <75 mVpk-pk
• Trigger Level: ±5.1 V (±51 V X10 mode) with 10 mV resolution
• Trigger Slope: Selectable positive or negative
• Auto Trigger: 100 Hz to 150 MHz, attenuator adjusts for signals exceeding 5.1 Vpk-pk
**Filtering**
• Low-Pass Filter: Selectable, 100 kHz bandwidth nominal
• Onboard Low-Pass: 50 kHz per channel
**Timebase**
• Standard Aging: 0.1 ppm/month
• Temperature Stability: 1 ppm (0° C to 40° C)
• Optional OCXO (Option 11): 0.01 ppm accuracy, 0.1 ppm stability (0° C to 60° C), 0.1 ppm/year aging
• Optional Rubidium Oscillator (Option 12): Available for long-term stability
## Typical Applications
Component characterization, signal integrity analysis, frequency synthesis validation, and automated production testing across RF and baseband domains.
