IFR 2959 Digital TDMA (IS-136A) Testing:
To simplify testing, digital phone tests mirror analog test procedures with alterations only to account for the different digital measurements and enhanced features available with modern TDMA (IS-136A) handsets. Set up and testing of IS-136A handsets can be fully automatic for all modes available in the handset, or it can be manual and interactive for diagnostic analysis. In addition to the normal registration and call control functions the IFR 2959 provides control over specialized TDMA (IS-136A) test features.
- All eleven RF power levels
- TDMA-specific call control such as time slot changes
- DTMF signaling from the handset
- RMS EVM (Error Vector Magnitude), phase error, droop, and I/Q origin offset (Carrier leak)
- RMS EVM over the first 10 symbols
- Voice loopback tests or actual voice checks with built-in VSELP and ACELP codecs including the energy (r0) variable of the VSELP codec
- BER verification of the phone’s receiver
- MAHO RSSI (Mobile Assisted Handoff-Receive Signal Strength Indication) on the alternate channel at -75, -85 and -95 dBm
- Full-featured Constellation display of the transmitter’s modulation
IFR 2959 CDPD Modem Testing:
CDPD (Cellular Digital Packet Data) is a separate packet radio service deployed on many AMPS cellular networks. The 2959’s CDPD test mode simulates the functions of Mobile Data Base Stations (MDBS) and Mobile Data Intermediate Systems (MD-IS), which provides the stimulus and response necessary to test mobile-end systems (M-ES) often called CDPD wireless modems. Though some handsets may have CDPD modems built in, they always operate separately from the phone, and are tested as autonomous devices. The external modems have an RF connector for their antennas, and a data connector for a laptop’s serial connector. Modems can be integrated into laptops, cellular phones or PDAs (Personal Digital Assistants). Testing can be as simple as connecting the external modem to a laptop loaded with the appropriate software to communicate with the CDPD modem, connect the 2959’s RF test port to the modem’s antenna connector, and then running a simple automatic test such as a Ping. Modems integrated into other devices do not require an auxiliary laptop connection for proper testing.
Not only do CDPD modems require traditional radio testing associated with cellular phones, the 2959 must be able to simulate the CDPD base station and the supporting network. This requires test analysis of the 19,200 baud GMSK RF carrier from the modem; protocol checks of the CDPD messages and associated compression, encryption, and authentication algorithms. As in cellular handset testing, you have control over specialized functions for CDPD tests:
• RF power and frequency
• Frequency stability and modulation indexes
• Receiver sensitivity
• Verification of CDPD protocol functions.
• GMSK (Gaussian Minimum Shift Keying) eye pattern
• Graphic burst analysis for relative on/off switching level confirmation and spectrum plot over the assigned channel.
