The Watkins-Johnson WJ-9477 is a precision tunable demodulator for signal reception and analysis across VLF through low-HF bands. It demodulates AM, FM, and SSB signals with 10 Hz tuning resolution and microprocessor control, serving electronic warfare, signal intelligence, and RF testing applications where frequency-selective demodulation and configurable IF filtering are essential.
Technical Specifications
• Frequency Range: 0.001 to 30 MHz (WJ-9477); 0 to 31 MHz (WJ-9477G)
• Tuning Resolution: 10 Hz
• IF Bandwidth Filters: 9 selectable bandwidths available
– WJ-9477: 3 kHz to 5 MHz
– WJ-9477G: 3.2 kHz to 6 MHz
• Physical: 3.5 inches H × 8.5 inches W × 21 inches D; 20 lbs
• Control: Microprocessor-based
– Key Features
• Demodulation modes: AM, FM, SSB (SSB optional on WJ-9477G)
• Multiple IF bandwidth options (3.2 kHz GP1, GP2, GP3 configurations)
• IF converter option (WJ-9477/IFC) for frequency translation
• Independent Single Sideband (ISB) reception capability
• Video filters (VF) for output signal shaping
• Video output attenuator (VOA) for precise level control
– Typical Applications
• Electronic warfare signal monitoring and analysis
• Signal intelligence (SIGINT) reception
• HF/VLF communication testing and characterization
• Multi-mode demodulation requiring configurable bandwidth
– Compatibility & Integration
Designed for standalone operation or system integration. Rack-mount form factor accommodates standard 19-inch installations. Microprocessor control enables precise, repeatable operation across diverse modulation types and bandwidth configurations.
