Advantest U3851 9kHz to 8GHz Cross Domain Analyzer

The Advantest U3851 is a cross-domain analyzer that integrates network analysis, spectrum analysis, and impedance analysis within a single instrument spanning 9 kHz to 8 GHz. It performs simultaneous two-channel measurement and analysis across time, amplitude, phase, and frequency domains - a capability enabling direct signal comparison and characterization of components and circuits. The instrument features industry-first two-channel phase synchronization for vector signal analysis, making it suited for R&D and manufacturing environments in telecommunications and broadcasting.

Technical Specifications

Frequency Coverage: 9 kHz to 8 GHz Time-Domain Analysis

• Maximum analysis bandwidth: 40 MHz


• Time resolution: 15.4 ns (at 40 MHz CBW) to 2 ms (at 100 Hz CBW)


• Supports Frequency vs. Time, Power vs. Time, and Phase vs. Time analysis


• Wide-band time-domain analysis available Capture Bandwidth: 100 Hz to 30 MHz (1-3 steps); extends to 40 MHz Sampling Rate: 500 Hz (at 100 Hz CBW) to 65 MHz (at 40 MHz CBW) for I/Q pair data per sample Inter-Channel Balance (at 1 GHz, CBW 100 kHz/ms, −30 dBm input)


• Amplitude: ±2.0 dB


• Phase: ±15 deg RF Input (L-input)


• Connector: N-type female, 50 Ω nominal impedance


• VSWR: <1.7:1 (10 MHz to 3.0 GHz); 3.0 GHz)


• Maximum safe input: +30 dBm (Pre-Amp OFF, ≥10 dB attenuator); +13 dBm (Pre-Amp ON, 0 dB attenuator)


• DC rating: ±15 VDC max RF Input (H-input)


• Maximum safe input: +10 dBm (0 dB attenuator)


• DC rating: ±25 VDC max Calibration Signal Output


• N-type female connector, 50 Ω impedance


• 20 MHz reference frequency

Key Features

• Two-channel phase-synchronized vector signal analysis


• Vector math operations (composition and decomposition via X function)


• High-purity spectrum analysis option for enhanced phase noise measurement


• FFT analysis capability


• Built-in pre-amplifier for high sensitivity and antenna loss compensation

Typical Applications Component and circuit characterization; phase noise measurements; multi-channel signal correlation in telecommunications and broadcast systems; time-domain and frequency-domain signal decomposition.

Compatibility & Integration Standard 50 Ω RF interface. Dual N-type connectors support independent measurement channels with synchronized timing and phase reference.