Electroencephalograph tester CMRR 3.0+

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Overview
The CMRR 3.0+ is a dedicated tester for measuring the Common Mode Rejection Ratio (CMRR) of EEG and ECG devices. It is engineered for R&D, compliance verification and production-line testing, meeting strict medical test-circuit requirements while providing stable, repeatable measurements.
Supports compliance testing of international medical standards: IEC 60601-2-25, IEC 60601-2-27, IEC 60601-2-47, IEC 60601-2-26, GB 9706.225, GB 9706.227, YY 9706.247, GB 9706.226, YY1079, YY1139, YY0782, YY0885, ANSI/AAMI EC11, ANSI/AAMI EC13.

Functions

• Built-in calibrated sine wave signal generator and voltage measurement circuit for accurate test signal output and real-time common-mode voltage monitoring.
• Double-layer internal shielding and specialized external design to minimize environmental noise interference.
• Wide voltage output range including up to 70.71 Vrms to extend CMRR test range up to 120 dB.
• Touchscreen for electrode selection and impedance overlay; physical knobs for fine capacitance adjustment.
• SDK support for automated test development and integration into production test systems.
• Optional Standard Assistant Software to simplify step-by-step compliance test procedures (sold separately).

Highlights

• All-in-one circuit design implements capacitance simulation and parallel impedance arrangements required by standards.
• Integrated calibrated generator overcomes insufficient voltage from general-purpose signal generators.
• Calibrated voltage measurement enables monitoring and adjustment of common-mode voltage relative to the generator output.
• Built-in MCU and electronic relays allow manual or automated switching of RC networks and voltage selections.
• Double-layer shielding and optional shielding covers for enhanced noise isolation and higher-CMRR testing.
• Achieves up to ~111 dB CMRR in unbalanced tests; expandable to 120 dB with higher output voltage.

Ordering information / Package contents

• Part No.: 100-CM00003 — Model No.: CMRR 3.0+. Advanced common mode rejection ratio tester with 11 compound terminals.
• Package contents: CMRR 3.0+ x 1; Top shielding cover x 1; Bottom shielding cover x 1; Compound terminal x 11; USB cable x 1; Grounding wire x 1; 12V Power adapter x 1 (power cord excluded).
• Optional software add-on pack for automated setups (part numbers HA0-CM04001, HA0-CM04002, HA0-CM04003, HA0-CM04005).
• Optional shielding case: model CM30ESBX for enhanced shielding performance (recommended for Holter testing).
• Optional calibration and warranty extension services available (part numbers YY0007, YY0008).

Technical specifications

• Supply voltage settings: 0.5 / 2.828 / 20 / 2 / (70.71) Vrms — ±1%*
• Common-mode (CM) point voltages: 1.414 / 10 / 1 / (35.355) Vrms — ±1% (0.25 Vrms ±2%)
• Frequency options: 50 / 60 / 100 / 120 Hz — ±1%
• Electrode with impedance: selectable via touchscreen — options: None / RA / LA / LL / V1 / V2 / V3 / V4 / V5 / V6 / ALL
• Electrode without impedance: selectable via touchscreen — options: RA / LA / LL / V1 / V2 / V3 / V4 / V5 / V6
• Imbalance resistance (R): 51 kΩ — 51 kΩ ±1%
• Imbalance capacitance (C): 47 nF — 47 nF ±5%
• DC offset: powered by replaceable preinstalled battery; applied on RA / LA / LL / V1~V6 — 300 mV ±1%; battery life up to 40 hrs (intermittent use)
• 100 pF capacitor measurement: uses 11:1 (110 MΩ : 10 MΩ) voltage divider for indirect measurement — 100 pF ±5%
• Operating environment: laboratory use; typical range 15–30°C, 10–75% RH. Note: 110 MΩ divider may be affected by humidity above 85%.
• Notes: *Voltage accuracy requires verification with a higher-precision multimeter.