The HP/Agilent 11757B Multipath Fading Simulator/Signature Test Set is a specialized instrument for comprehensive testing of wireless communication systems under realistic signal propagation conditions. It simulates multipath fading effects to validate receiver and transceiver performance in R&D and manufacturing environments where precise fading emulation is critical. The instrument generates both static and dynamic multipath fades by introducing a controlled notch within the transmission bandwidth, enabling direct measurement of equalizer performance and fade margin characteristics.
## Technical Specifications
The 11757B employs a simplified 3-ray multipath model with precisely controlled notch depth up to 40 dB across 1.0 MHz to 40 MHz bandwidths while maintaining constant average gain. Intermodulation distortion products measure typically less than −50 dBc, ensuring that observed performance degradation results from simulated fading rather than test equipment artifacts.
Frequency coverage operates at 70 MHz ±20 MHz standard IF. Option 140 provides 140 MHz IF coverage; Option 147 supports both 70 MHz and 140 MHz. Option H02 increases input/output power capability to +4 dBm. Auxiliary output is provided on the rear panel, mirroring front panel output characteristics.
## Key Features
• M-Curve signature capability for radio performance assessment with and without multipath protection
• Measures static M-curves, dynamic M- and S-curves, recovery signatures, recovery times, and dispersive fade margin
• M-Curve signature measurement completes in less than one minute with hardcopy output
• Loads statistical or measured fading data into non-volatile memory
• Supports up to 10 complex fading event simulations for accelerated radio stress testing
• On-board temperature compensation and voltage stabilization for improved measurement accuracy
• Warranted specifications valid 15° to 35° C after 15-minute warm-up
## Compatibility & Integration
HP-IB (General Purpose Interface Bus) port enables remote access and automatic data capture with parameter control for computer-based analysis. Ethernet connectivity supports remote access and data acquisition. Both interfaces allow automated parameter configuration and measurement streaming for system integration.
