The Marconi IFR Aeroflex 2957A is a specialized radio communication test set engineered for AMPS (Advanced Mobile Phone System) equipment validation. Built on the 2955 series platform with dedicated AMPS-specific software and cellular adapter, it delivers base station simulation and comprehensive DC, audio, and RF testing for mobile radios. The instrument supports manual and fully automated operation modes with remote GPIB or RS-232 connectivity, meeting requirements across AMPS, E-AMPS, N-AMPS, TACS, PMR, and EDACS standards.
Technical Specifications
RF Performance
• Signal generator: 400 kHz to 1.05 GHz (2957A variant: up to 1000 MHz)
• Output power: +5 dBm (overrange to +7 dBm)
• Level accuracy: ±2 dB above −127 dBm
• Spectrum analyzer dynamic range: 50–70 dB with tracking generator for filter/duplexer alignment
• Analyzer spans: 100 Hz/division to full span
System Architecture
• Base unit: Marconi 2955 series foundation
• Display: Menu-driven CRT interface
• Preset storage: 26 stores for standard settings
• Weight: Under 15 kg (33 lbs) for portable variants
• Power: AC supply (up to 400 Hz) or vehicle supply
AMPS Configuration
• System identity: 5-digit decimal (default 00002)
• Control channel: 0–1023 (default 334)
• Voice channels: 0–1023 (first default 1; last default 666)
• Mobile number (MIN): XXX-XXX-XXXX format
• Digital colour code: 0–3 (default 0)
• Narrowband (N-AMPS) support enabled
• DSAT/DST capable (instruments after May 1991)
– Key Features
• Base station simulation with full signalling
• DTMF in-conversation transmission via keypad
• SAT deviation parameter control
• System A/B channel allocation (313–333 System A; 334–354 System B)
• Built-in self-test and operator guidance
• Fully automated test executive with manual override
– Typical Applications
• Mobile radio commissioning and field service
• Base station transceiver validation
• Cellular system troubleshooting and alignment
• Duplexer and filter characterization
– Compatibility & Integration
Remote operation via GPIB or RS-232 enables integration into automated test environments and laboratory setups for extended cellular radio validation.
