The Stanford Research Systems SG396 is a 6 GHz vector signal generator engineered for RF and microwave development requiring analog and vector modulation in a single platform. It combines Rational Approximation Frequency Synthesis (RAFS) with dual arbitrary waveform generators to deliver spur-free outputs, 1 μHz frequency resolution, and -116 dBc/Hz phase noise at 1 GHz. The instrument supports ASK, FSK, MSK, PSK, QAM, and VSB modulation with factory presets for GSM, EDGE, W-CDMA, APCO-25, DECT, NADC, PDC, ATSC-DTV, and TETRA standards. Frequency switching occurs in under 8 ms to within 1 ppm. Dual baseband generators operate at 125 MHz with symbol rates to 6 MHz, while 300 MHz modulation bandwidth accommodates advanced I/Q applications. Digitally controlled attenuation spans 156 steps to -130 dB, with up to +25 dB gain and calibrated power control via a 40,000-element memory matrix. Standard and optional rubidium timebases support frequency stability of 1 × 10⁻¹¹ (1 s Allan variance). RF output via Type N connector (above 950 kHz) and BNC for DC to 62.5 MHz signals. Direct AWGN injection capability supports noise-injection testing workflows.
Technical Specifications
• Frequency range: DC to 6.075 GHz
• Frequency resolution: 1 μHz
• Frequency synthesis: Rational Approximation Frequency Synthesis (RAFS)
• Frequency switching time: 40 dBc (>35 dBc above 4 GHz)
• Modulation bandwidth: 300 MHz
• I/Q inputs: 50 Ω, ±0.5 V
• Dual arbitrary waveform generators: 125 MHz operation, up to 6 MHz symbol rate
• AM modulation: 0 to 100% (0.1% resolution)
• AM distortion: <1% (fC < 62.5 MHz, fM = 1 kHz); 62.5 MHz, fM = 1 kHz)
• FM frequency deviation: 0.1 Hz minimum; frequency-dependent maximum
– Key Features
• Spur-free synthesis via RAFS topology
• Vector modulation: ASK, FSK, MSK, PSK, QAM, VSB, and custom I/Q
• PSK derivatives: BPSK, QPSK, OQPSK, DQPSK, π/4DQPSK, 8PSK, 16PSK, 3π/8 8PSK
• QAM variants: 4, 16, 32, and higher orders
• VSB variants: 8VSB, 16VSB
• Standard modulation presets: GSM, EDGE, W-CDMA, APCO-25, DECT, NADC, PDC, ATSC-DTV, TETRA
• Direct AWGN injection into signal path
• Calibrated power control with 40,000-element memory matrix
• Ovenized or optional rubidium timebase
– Typical Applications
• Wireless communications development and testing
• Radar system characterization
• Satellite communications signal generation
• Modulation validation across multiple standards
• Noise injection and receiver stress testing
– Compatibility & Integration
• RF output: Type N connector (≥950 kHz)
• Baseband output: BNC (DC to 62.5 MHz)
• External modulation: ±0.5 V I/Q inputs at 50 Ω impedance
