# Agilent 35665A 2-Channel DC to 102.4 kHz Dynamic Signal Analyzer (Pre-Owned) # Agilent 35665A 2-Channel DC to 102.4 kHz Dynamic Signal Analyzer (Pre-Owned) ## Key Features At A Glance - Two-channel dynamic signal analysis from DC to 102.4 kHz (single-channel) or 51.2 kHz (dual-channel) - Frequency resolution down to 122 µHz with 100/200/400/800 line FFT options and ±30 ppm frequency accuracy - Real-time bandwidth ≥12.8 kHz with fast average on; up to 33 averages/second in single-channel mode (typical) - Input ranges from +27 dBVrms (31.7 Vpk) down to -51 dBVrms (3.99 mVpk) in 2 dB steps - Spurious-free dynamic range below -72 dBfs including spurs, harmonic and intermodulation distortion, and alias products - Built-in source output (±5 V peak) supporting sine, random, pink noise, and chirp waveforms - Integrated tachometer/trigger inputs with 5 to 220,759 RPM range and ±100 ppm RPM accuracy - IEPE signal conditioning standard (4.25 ±1.5 mA current source) for direct accelerometer measurements The Agilent 35665A is a 2-channel dynamic signal analyzer covering DC to 102.4 kHz in single-channel mode and DC to 51.2 kHz when both channels are active. It performs FFT-based frequency-domain analysis with 100, 200, 400, or 800 lines of resolution per measurement, and frequency accuracy of ±30 ppm. The instrument combines dual-channel input acquisition, an integrated source output for stimulus-response measurements, and trigger and tachometer inputs for rotating-machinery analysis in a single benchtop chassis. Dynamic signal analyzers like the 35665A are used wherever an engineer needs to characterize signals in the frequency domain rather than the time domain — measuring amplitude versus frequency, phase relationships between two signals, and transfer functions of physical or electronic systems. The 35665A's IEPE signal conditioning, tachometer input with pulses-per-revolution settings from 0.5 to 2048, and ±5 V peak source output position it for vibration measurement on accelerometers, structural and modal analysis using stimulus-response methods, and order-tracking measurements on rotating equipment when ordered with the appropriate option. ## Brand Heritage Hewlett-Packard's test and measurement business was spun out as Agilent Technologies in 1999. In 2014 the electronic measurement portion of Agilent was transferred to Keysight Technologies, while Agilent retained its life-sciences and chemical-analysis businesses. Instruments originally sold under the HP and Agilent labels — including the 35665A — trace their support and calibration lineage through this corporate sequence. ## Product Core & Specifications Specification Value Frequency Range, One Channel Mode (Ch. 1) 102.4 kHz Range, Two Channel Mode (Ch 1 & 2) 51.2 kHz Resolution 100, 200, 400 or 800 lines resolution Minimum Frequency Resolution, One Channel Mode 244 µHz Minimum Frequency Resolution, Two Channel Mode 122 µHz Spans, One Channel Mode 102.4 kHz to 0.19531 Hz Spans, Two Channel Mode 51.2 kHz to 0.097656 Hz Accuracy ±30 ppm Real Time Bandwidth (Fast Average On) ≥12.8 kHz Measurement Rate, One Channel Mode (401 pt FFT, fast avg on) ≥33 averages/second (typical) Measurement Rate, Two Channel Mode ≥15 averages/second (typical) Display Update Rate ≥8 updates/second (typical) Amplitude / Phase Input Ranges (full scale) +27 dBVrms (31.7 Vpk) to -51 dBVrms (3.99 mVpk) in 2 dB steps Amplitude Resolution 0.016% of full scale (typical) Absolute Amplitude Accuracy ±2.92% (0.25 dB) of reading, ±0.025% of full scale Cross-Channel Gain Accuracy (Source = Full scale) ±0.04 dB Cross-Channel Gain Accuracy (Source = -20 dB full scale) ±0.08 dB Cross-Channel Phase Accuracy (Source = Full scale) ±0.5 deg Cross-Channel Phase Accuracy (Source = -20 dB full scale) ±0.5 deg Dynamic Range Full Span FFT Noise Floor (Input Range 27 to -35 dBVrms) <-76 dBfs (-85 dBfs typical) Full Span FFT Noise Floor (Input Range -37 to -51 dBVrms) <(-112 - Range) dBfs Spurious Free Dynamic Range <-72 dBfs (includes spurs, harmonic distortion, intermodulation distortion, alias products) Zoom Mode Alias Responses (1.5% to 98.5% of frequency span) <-72 dBfs Zoom Mode Alias Responses (Lower and Upper 1.5% of span) <-65 dBfs Input Noise Level (Above 1280 Hz) <-140 dBVrms/√Hz Input Noise Level (160 Hz to 1.28 kHz, 6.4 kHz span) <-130 dBVrms/√Hz Input Input Ranges \-51 dBVrms to +27 dBVrms Input Impedance 1 MΩ ±30%, ≤100 pF Low Side to Chassis Impedance (Floating Mode) 1 MΩ ±30% (typical), <0.01 µF (typical) AC Coupling <3 dB rolloff at 1 Hz Common Mode Rejection (-51 to -11 dBVrms ranges) \>80 dB (typical) Common Mode Rejection (-9 to +9 dBVrms ranges) \>60 dB (typical) Common Mode Rejection (+11 to +27 dBVrms ranges) \>40 dB (typical) Common Mode Range (floating mode) ±4 V pk IEPE Signal Conditioning Current Source 4.25 ±1.5 mA IEPE Open Circuit Voltage +26 to +32 Vdc Trigger / Tachometer Trigger Modes Internal, External TTL, Source, HP-IB Maximum Trigger Delay (Post Trigger) 8191 seconds Maximum Trigger Delay (Pre Trigger) 8191 samples Pulses Per Revolution 0.5, 1 to 2048 (integer steps) RPM Accuracy ±100 ppm Trigger Level Range (Low) \-4 V to +4 V Trigger Level Range (High) \-20 V to +20 V Trigger Level Resolution (Low Range) 100 mV Trigger Level Resolution (High Range) 500 mV RPM Range 5 < RPM < 220,759 Maximum Trigger Pulse Rate 800 kHz Source Output Amplitude Range ±5 V peak Amplitude Resolution (Voltage ≥ 0.2 Vrms) 2.5 mVpeak Amplitude Resolution (Voltage < 0.2 Vrms) 0.25 mVpeak Residual DC Offset ±10.0 mV Output Impedance <5 Ω Source Type Sine, random, pink noise, chirp **Important:** Single-channel and two-channel modes have different maximum frequency spans: 102.4 kHz in one-channel mode and 51.2 kHz when both channels are active. Confirm the channel configuration required by the intended measurement matches the available span before deployment.**Important:** Typical specifications are non-warranted performance specifications included to provide general product information.**Important:** dBfs values are relative to full scale amplitude range; full scale is approximately 2 dB below ADC overload.**Important:** Option 1D1 Real Time Octave Analysis conforms to ANSI Standard S1.11-1986, Order 3, Type 1-D (Extended and Optional Frequency Ranges) and IEC Standard 651-1979 Type 0 Impulse, and ANSI S1.4. ## About this used unit - Warranty included - Functional verification included - Standard Calibration Upgrade Options: No Calibration Required, NIST Traceable, Z540.1 or ISO 17025 with Data, Z540.3 Guardbanding with Data. - Note that unnecessary accessories may not be included (contact Test Architect to confirm). **Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.** ## Details - **Price:** 0.0 USD - **Vendor:** Agilent - **Type:** Spec An - **Tags:** Agilent, Agilent Keysight, Analyzers, Manufacturers, product_manual_group_1, Product_used, Signal ## Variants | Variant | Price | Available | |---------|-------|-----------| | None | 0.00 USD | In stock | | NIST Traceable | 0.00 USD | In stock | | NIST Traceable with Full Data | 0.00 USD | In stock | | ISO IEC 17025 Accredited | 0.00 USD | In stock | ## Images - 35665A HP Signal Analyzer --- > Source: [ValueTronics](https://valuetronics.com/products/35665a-agilent-signal-analyzer-used) > Updated: 2026-05-30