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CMC251
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CMC251
Features & Benefits
CMC251
- 1 Hz to 100 MHz (CH 1), 80 MHz to 1.3 GHz (CH 2)
- ±1 ppm Time Base
- Period Average, Period, Frequency, Totalize Self-test
- Display Hold
- Remote Start/Stop
- One Year Warranty
Applications
- Training
- Manufacturing
- Production Test
- Field Repair
- Bench Calibration and Repair
- Product Design
- Laboratory and Research
- Education
CMC251
The CMC251 1.3 GHz Multifunction Counter measures the frequency of sine, square and triangle waves from 1 Hz to 1.3 GHz. The CMC251 also provides period, totalize and pulse width measurements. The counter has two input channels. Channel A is a standard 1 MΩ input for frequency measurements up to 100 MHz. Channel B is a 50 Ω terminated input for use in high-frequency systems. This counter is of interest to radio amateurs because of its ability to measure high-frequency systems. The temperature-compensated, crystal-controlled time base is stable to ±1 part per million per year.
Characteristics
Channel A
Frequency Range - 1 Hz to 100 MHz.
Sensitivity - 20 mVRMS, 1 Hz to 30 MHz; 50 mVRMS, 30 MHz to 100 MHz.
Attenuation - 3 V to 42 V (HI); 50 mV to 5 V (LO).
Max. Input Voltage - 1 Hz to 5 MHz: 42 V pk. 5 MHz to 100 MHz: 4.9 V pk.
Low Pass Filter - -3 dB at 100 kHz.
Impedance - 1.0 MΩ, paralleled by 40 pF.
Channel B
Frequency Range - 80 MHz to 1.3 GHz.
Sensitivity - 5 mVRMS, 80 MHz to 600 MHz; 15 mVRMS, 600 MHz to 900 MHz; 35 mVRMS, 900 MHz to 1.3 GHz.
Impedance - 50 Ω.
Max. Input Voltage - 1 VRMS.
Period
Range - Direct: 0.4 µs to 1.0 s. Prescale: 0.04 µs to 1.0 s.
Resolution - Direct: 100 ps to 100 ns. Prescale: 10 ps to 10 ns.
Min. Pulse Width - Direct: 0.2 µs. Prescale: 20 ns.
Frequency Range - Direct: 1 Hz to 2.5 MHz. Prescale: 1 Hz to 25 MHz.
Events Averaged (N) - 1, 10, 100, 1000, 10,000 cycles.
Totalize Range - 0 to 99,999,999.
Pulse Width
Range - 0.25 µs to 0.5 s.
Period Range - 100 ps to 100 ns.
Events Averaged (N) - 1, 10, 100, or 1000 cycles.
Time Base Stability
Temperature - <1 ppm from 0 °C to 40 °C.
10% Line Voltage Change - <0.4 ppm.
Accuracy
Frequency - ±(time base error + 1 count).
Period - ±(time base error + 1 count + trigger error).
Pulse Width - ±(time base error + 1 count + trigger error + 10 ns).
Plus
Selectable Slope - No.
Ratio CH A: CH B - No.
Display Hold - Yes.
Remote Start/Stop - Yes.
Time Interval CH A: CH B - No.
Safety - UL1244, CSA231, EN61010-1.
EMC - Meets Directive 89/336/EEC.
Ordering Information
CMC251
1.3 GHz Frequency Counter with High Stability Time Base.
Includes: Operator's manual, US power cord, one year warranty.
Available Accessories
10X Probe, 250 MHz - Order P6106A.
Tektronix Measurement Service
Tektronix CAL and REP service programs allow you to prepurchase genuine Return to Tektronix Services - ask your Distributor for details.
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Product manufactured in ISO 9002 registered facilities. 3MW-15103-0a