RM2-PSP
2 Channel Psophometer
The RM2-PSP is a high-performance, dual-channel Psophometer and Psophometric filter designed in accordance with ITU-T Recommendation O.41 (previously CCITT recommendation). Built with precision and reliability in mind, the RM2-PSP is ideal for measuring noise levels on speech transmission circuits—essential for ensuring the integrity of communication systems used in railway networks, emergency services, and military operations.
Still widely deployed across the globe, the RM2-PSP remains a trusted standard for assessing perceptible noise in critical voice communication lines.
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Key Features
- Compliant with ITU-T O.41 for accurate, standardised noise measurement
- KEMO® FM-1200/PSP Filter Module for Psophometric weighting
- Fully Independent Dual Channels with matched performance
- Selectable Gain Levels: x1, x10, x100, x1000
- Filtered & Amplified Output plus RMS DC conversion
- Input Level Indicators: Green (1V), Amber (7V), Red (9V), Overload (>10V)
- Robust Construction: Aluminium chassis, stainless steel front/rear
- 19″ Rack Mountable (1U height) with optional transit case
- Global Compatibility: 110V or 240V AC input
What is a Psophometer?
Derived from the Greek word psóphos meaning noise, a Psophometer is a specialized instrument used to measure the perceived level of noise on telephone circuits. By applying frequency-weighted filters that mimic human hearing sensitivity, the RM2-PSP allows engineers to quantify how noise impacts the quality of voice transmissions, vital for evaluating and maintaining critical communication systems.
Rear Panel Outputs (Per Channel)
Each channel provides 4 dedicated BNC outputs:
- Input Monitor – Unity gain (available on front and rear)
- Amplified Output – Selectable gain up to x1000 (10V peak swing)
- Filtered Amplified Output – In accordance with ITU-T O.41
- RMS DC Output – 1V RMS = 1V DC ±5% tolerance
Technical Specifications
| Parameter | Specification |
|---|---|
| Channels | 2 fully independent |
| Input Impedance | 600Ω |
| Output Impedance | 50Ω |
| Gain Options | x1, x10 (20dB), x100 (40dB), x1000 (60dB) |
| Gain Matching | Within 0.1dB at 1kHz |
| Output Voltage Swing | ±12V max |
| RMS Calibrated Range | 0.1 to 1V |
| RMS to DC Gain | 1:1 ±0.5dB |
| Output Noise | < 300 nV/√Hz typical |
| Frequency Response | ITU-T O.41 (1994) |
| Input Frequency Range | 100Hz – 6kHz |
| Max Gain | x1000 |
| AC Input Power | 105–125V or 210–250V AC, 50–60Hz |
| AC Supply Input Power | 25VA |
Mechanical
| Parameter | Specification |
| Dimensions | 420mm (W) x 390mm (D) x 50mm (H) |
| Mass | 4.9 kg |
| Enclosure Material | Aluminium chassis, stainless steel front/rear |
| Operating Temperature | 5°C to 35°C |
| Mounting | 19” rack, 1U height |
Safety & Connectivity
- Input Isolation: 1500V to case and outputs
- Signal Inputs: Max 50mW (AC+DC), 6V RMS, 3mA DC
- Earth Connection: Via IEC mains; signal 0V floating but accessible on rear 4mm connectors
Applications
