Agilent/Keysight 3575A

The Agilent/Keysight 3575A is a dual-channel gain-phase meter that measures amplitude and phase across a 1 Hz to 13 MHz broadband range without requiring tuning. It delivers direct characterization of transfer functions, impedance ratios, and absolute signal levels for amplifiers, filters, feedback control systems, and RF/audio devices.

Technical Specifications

Frequency Range: 1 Hz to 13 MHz
Input Level Range: 200 µV rms to 20 V rms
Input Impedance: 1 MΩ shunted by 30 pF
Input Protection: ±40 V dc, 20 V rms maximum
Channels: 2 Amplitude Measurement

• Range: 100 dB


• Dynamic Range: 80 dB


• Resolution: 0.1 dB Phase Measurement


• Range: ±180° with 12° overrange (±192°)


• Resolution: 0.1°


• Accuracy: <2° error at 30 dB signal-to-noise ratio Display & Outputs


• Three-digit selectable readout (amplitude or phase); optional dual meters


• Update Rate: 4 Hz


• Analog Phase Output: 10 mV/degree


• Analog Amplitude Output: 10 mV/dB or dBV (1 kΩ impedance)


• Rear-panel BNC connectors support external data logging and recorder integration Physical


• Dimensions: 88 mm (H) × 425 mm (W) × 337 mm (D)


• Weight: 8.3 kg net; 11.3 kg shipping


• Power: 115 V/230 V ±10%, 48–440 Hz, 40 VA


• Operating: 0–55°C; Storage: −40–75°C


• Humidity: ≤95% relative humidity (operating)

Key Features

• Measures sine, square, and triangular waveforms


• Harmonic rejection eliminates phase errors from even harmonics and in-phase odd harmonics


• Selectable three-stage internal filter bank for noise mitigation


• No tuning required across full frequency span


• Simultaneous dual-channel absolute level measurement capability

Typical Applications

• Bode plot generation for stability margin analysis


• Feedback amplifier characterization


• Component impedance and transfer function measurement


• Control system frequency response evaluation


• RF and audio circuit validation

Compatibility & Integration Analog outputs drive external recorders and measurement instruments for automated data acquisition. Optional dual-meter configuration and BCD output with remote control (Option 002) support laboratory integration workflows.