HP / Agilent 3575A Gain/Phase Meter

The HP/Agilent 3575A Gain/Phase Meter is a dual-channel AC analyzer that measures amplitude and phase parameters from 1 Hz to 13 MHz. It delivers absolute amplitude levels, amplitude ratios, phase difference, envelope delay, return loss, complex impedance, insertion loss, and transfer functions with high precision across noise and distortion.

This instrument supports sine, square, and triangular waveforms with an 80 dB dynamic range and 100 dB measurement span. Amplitude resolution reaches 0.1 dB across 200 µV rms to 20 V rms inputs, expandable to 200 V rms with 10:1 divider probes. Phase measurements span ±180 degrees (with 12-degree overrange) at 0.1-degree resolution. Dual phase detectors ensure accurate phase characterization in high-noise environments.

Input impedance is 1 MΩ shunted by 30 pF. A 20 dB input attenuator extends operating range to 120 dB when paired with 10:1 probes. Three selectable internal filters provide additional noise rejection. The 3.5-digit LED display presents simultaneous amplitude and phase readings with Option 001.

– Technical Specifications

• Frequency Range: 1 Hz to 13 MHz
• Channels: 2
• Amplitude Dynamic Range: 80 dB
• Amplitude Measurement Range: 100 dB (120 dB with attenuator and probes)
• Amplitude Resolution: 0.1 dB
• Input Voltage Range: 200 µV rms to 20 V rms (expandable to 200 V rms with 10:1 probes)
• Phase Range: ±180 degrees (±12 degrees overrange)
• Phase Resolution: 0.1 degrees
• Input Impedance: 1 MΩ || 30 pF
• Power: 115 V / 230 V ±10%, 48–440 Hz, 40 VA

– Key Features

• Dual phase detectors for noise-robust measurements
• Selectable internal filters for enhanced signal clarity
• Analog outputs (BNC): 10 mV/degree phase, 10 mV/dB amplitude; 1 kΩ output impedance
• BCD outputs available (Options 002, 003) with remote control capability
• Compact 88 mm H × 425 mm W × 337 mm D; 8.3 kg net weight

– Typical Applications

• Feedback system characterization and transfer function measurement
• Network device gain and phase profiling
• Transmission line impedance and insertion loss analysis
• Component qualification in R&D and quality control

– Compatibility & Integration

Option 001 enables dual panel meters. Options 002 and 003 add BCD outputs with remote control; 002 uses negative true logic, 003 positive true logic. Rear-panel analog outputs facilitate external data logging and instrumentation integration.