Showing Results for Rohde & Schwarz CMD80

Rohde & Schwarz, a world market leader in mobile-radio measurements, and its US partner company Tektronix have jointly developed a mobile-phone tester for the US mobile-radio system CDMA to IS95 standard: Digital Radiocommunication Tester CMD80. It also incorporates the technology needed for measurements in the predecessor analog AMPS network, which is still in use. CMD80 measures the RF and AF parameters of mobile stations supporting both standards or dual-mode equipment in development, production and service with the aid of network-specific signalling. It covers the 800-MHz band (cellular radio mobiles for CDMA and analog AMPS), the 1900-MHz band (PCS mobiles for CDMA, PCS = personal communication system) and the 1700-MHz band for the Korean variant of CDMA.

Measurements are based on ultramodern digital signal processing. The results are thus available within the shortest possible time, which means an enormous benefit in speed-dictated mass production. DSP technology has two important benefits: measurement functions can be enhanced by software upgrades and new measurement techniques can be added solely by software modifications. The individual measurements for the various standards are derived directly from the relevant specifications and are preconfigured. Measurements can thus be performed without in-depth knowledge of the relevant network.

Basically, CMD80 provides two different measurement modes for each network. Measurements can be performed either as a module test (ie without call setup to the DUT) or as a manual test with full signaling. In the latter case a call setup for performing the measurement can be made both from the base station (which is simulated by the CMD80) and from the mobile. In this mode it is also possible to set up a call with voice loopback. The audio data picked up by the microphone of the mobile phone are buffered in the CMD80 and reflected to the mobile under test after a delay of about two seconds. In this way speech quality of the DUT can be verified.

In the signaling mode, implicit hand-offs can be made within the same standard (ie a D-AMPS handoff to another digital traffic channel – a new channel number – or changeover to another timeslot at the same TDMA frequency) as well as handoffs to other standards, if defined. This is an important criterion for testing multimode/ multiband mobile phones. The measurements themselves are adapted to the relevant transmission standard.

The following CMD80 specifications are for CDMA communications only.

Signal Generator

• Frequency range
  • US Cellular: 869 MHz to 894 MHz
  • Japan Cellular: 832 MHz to 870 MHz
  • China Cellular: 934 MHz to 969 MHz
  • PCS (US): 1930 MHz to 1990 MHz
  • PCS (Korea): 1805 MHz to 1870 MHz
• Frequency resolution: 1 Hz
• Output level
  • RF IN/OUT: -124 dBm to -20 dBm
  • RF OUT: 2 -105 dBm to 0 dBm
  • Resolution: 0.1 dB
• Modulation: QPSK
• Carrier suppression: 30 dB

Analyzer

• Frequency range
  • US Cellular: 824 MHz to 849 MHz
  • Japan Cellular: 887 MHz to 925 MHz
  • China Cellular: 889 MHz to 924 MHz
  • PCS (US): 1850 MHz to 1910 MHz
  • PCS (Korea): 1715 MHz to 1780 MHz
• Frequency resolution: 1 Hz
• Power
  • Reference level range: RF IN/OUT (full scale) is -28 dBm to +41 dBm,
    RF IN 2 (full scale) is -69 dBm to 0 dBm
  • Dynamic range: 50 dB below reference level
• Demodulation: O-QPSK
• Demodulation frequency measurement range: -3 kHz to +3 kHz
• Rate set support
  • Rate set 1 (8 k): standard
  • Rate set 2 (13 k): option B14
• AWGN generator (option B81)
  • Equivalent noise bandwidth: 1.8 MHz typical
  • Gain adjustment range: -20 dB to +6 dB of forward channel power
• Signaling digital modes: IS-95, UB-IS-95, J-STD008, T53