Rohde & Schwarz URE Series Broadband RMS Voltmeters
2 models with full specifications from Rohde & Schwarz.
This technical guide reviews the Rohde & Schwarz URE series of high-precision, broadband RMS voltmeters, focusing on the URE2 and URE3 models. Designed for engineers and test system evaluators, these instruments provide highly accurate true RMS measurements of both AC and AC+DC signals. Both models employ a patented rectifier circuit and a microprocessor-controlled autocalibration system with nonvolatile correction factor storage to maintain measurement integrity. This guide explains the core architectural features shared across the series and contrasts the individual models based on frequency limits, DC voltage capability, configuration memory, and input interface options, helping technical buyers select the correct instrument for their test environment.
- AC Voltage Range
- 50 µV to 300 V
- Measurement Resolution
- 4.5 digits
- True RMS Converter
- Patented rectifier circuit
- Crest Factor Range
- Up to 7
Models in this series
Shared Architecture and True RMS Performance
The Rohde & Schwarz URE series is engineered for high-accuracy broadband RMS measurement, utilizing a patented rectifier circuit to resolve both AC and AC+DC signals. Both instruments support a crest factor up to 7, allowing for precise evaluation of complex, non-sinusoidal waveforms. To maintain high accuracy over time and temperature variations, both models feature microprocessor-controlled autocalibration with nonvolatile storage of correction factors.
Each instrument includes a 4.5-digit LCD digital display alongside an analog bar graph display with a selectable scale. A built-in zero function is standard on both models, designed to compensate for external noise voltages as well as inherent instrument noise. Additionally, both devices share identical physical dimensions (219 mm × 103 mm × 350 mm) and operate within a temperature range of 0 °C to +50 °C.
Key Differences and Model Selection
While the Rohde & Schwarz URE2 and Rohde & Schwarz URE3 share the same underlying measurement architecture, they differ in frequency limits, input characteristics, and memory features:
- Frequency Coverage: The URE2 covers a range from DC and 10 Hz up to 25 MHz. The URE3 extends this performance, offering a frequency measurement range up to 30 MHz.
- DC Measurement Range: The URE3 explicitly defines a DC voltage measurement range of 0 to 300 V.
- Frequency Response Correction: The URE3 includes automatic frequency response correction, which utilizes the measured frequency internally to enhance overall accuracy at high frequencies.
- Setup Memory: The URE3 features internal memory capable of storing up to 9 complete instrument configurations, allowing rapid test setup transitions. The URE2 does not include this configuration memory.
- Input Capacitance: The URE2 lists a specific input capacitance of 25 pF at its 1 MΩ input, whereas the URE3 specifies a 1 MΩ input impedance.
Interfaces and System Integration
Both the URE2 and URE3 models are equipped with a GPIB (IEEE-488) interface as standard, enabling integration into automated test systems. However, the URE3 offers additional hardware options for complex test setups.
Optional interfaces for the URE3 include a ready output, a trigger input, a TTL frequency counter input, and a dual-channel analog output via the specialized In/Out option. Mechanically, the URE2 weighs 4.8 kg, while the URE3 is slightly lighter at 4.6 kg.
Frequently asked questions
- What is the maximum voltage the URE series can safely measure?
- Both the Rohde & Schwarz URE2 and URE3 have a maximum continuous input voltage rating of 300 V RMS.
- Does the URE series support automated systems?
- Yes, both the URE2 and URE3 feature a standard GPIB (IEEE-488) interface for remote control and data transfer.
- Can the URE3 measure DC voltage directly?
- Yes, the URE3 features a dedicated DC voltage measurement range from 0 to 300 V.