Rohde & Schwarz CMD Series GSM Radiocommunication Testers
2 models with full specifications from Rohde & Schwarz.
The Rohde & Schwarz CMD Series consists of digital radiocommunication testers designed for GSM networks. This family is split into specialized instruments for testing either mobile devices or infrastructure. The CMD55 is tailored for GSM mobile stations, supporting signaling and transmitter or receiver testing on mobile devices. The CMD57 is engineered for measurements on GSM base stations (BTS) and BTS modules. Both systems provide testing capabilities for developers, production environments, and service engineers, supporting major GSM frequency bands and offering standard integration interfaces.
- CMD55 Applications
- GSM Phase 1 and Phase 2 Mobile Stations
- CMD57 Applications
- GSM Base Stations (BTS) and BTS Modules
- CMD55 Reference Frequency
- 10 MHz
- CMD57 Dynamic Range
- >72 dB
Models in this series
Mobile Station Testing with the CMD55
The CMD55 is a dedicated mobile station test set. It supports multi-band operations covering GSM900 (including E-GSM), DCS1800, and PCS1900 networks. It allows for complete Phase 1 and Phase 2 mobile station testing with GMSK modulation.
Its integrated RF generator operates across several frequency ranges depending on the band: 925 MHz to 960 MHz for GSM900, 1805 MHz to 1880 MHz for DCS1800, and 1930 MHz to 1990 MHz for PCS1900. In addition to RF generation, the instrument performs signaling and call processing tests, including call setup, call release, call clearing, and handover (channel, band, and power level). For receiver sensitivity evaluations, the unit measures Bit Error Rate (BER), Residual BER (RBER), and Fast BER.
Base Station and Module Testing with the CMD57
The CMD57 is optimized for GSM base station (BTS) and BTS module testing. It natively supports GSM900, E-GSM, and UIC (European train radiotelephony), with optional support for GSM1800 and GSM1900. Designed to work without complete signaling setups, the CMD57 has a dedicated module test functionality for testing transmitter components without synchronization.
To check transmitter switching and modulation, the instrument features a dynamic range exceeding 72 dB and adjacent timeslot rejection up to 50 dB. It performs precise measurements for phase and frequency error (including statistical functions), transmitter power ramp, and spectrum due to modulation or switching. The integrated RF monitor bandwidths of 30 kHz and 100 kHz permit these measurements without requiring an external spectrum analyzer.
Physical Interfaces and Remote Control
Both instruments in the series are built for benchtop or rackmount integration, featuring standard communication ports. The CMD55 includes GPIB (IEEE-488.2), a 9-pin RS-232-C port, and a Centronics printer port. The CMD57 includes RS-232-C and IEC/IEEE-488 (GPIB) interfaces, and is controlled via SCPI-compatible remote control protocols.
For power requirements, both systems run on 100 V to 240 V AC (±10%), with the CMD55 drawing approximately 120 W at 50/60 Hz, while the CMD57 accepts 50 Hz to 60 Hz / 400 Hz. The CMD55 weighs 14 kg with dimensions of 435 mm × 165 mm × 460 mm, and the CMD57 measures 435 mm × 170 mm × 415 mm.
Frequently asked questions
- What standard modulation format is used by the CMD55?
- The CMD55 uses GMSK (Gaussian Minimum Shift Keying) modulation for GSM mobile station testing.
- Does the CMD57 require signaling to test transmitter modules?
- No. The CMD57 includes a module test functionality that allows complete transmitter measurements without signaling or time synchronization.
- What interfaces does the CMD57 support for Bit Error Rate (BER) measurements?
- The CMD57 supports BER measurements through several interfaces: the Abis interface, IEEE bus, RS-232-C interface, BTS loopback, and CMD loopback.