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PSM3750 Frequency Response Analyzer: 10µHz–50MHz, Isolated Inputs (500Vpk), Isolated AC+DC Coupled Generator

The PSM3750 builds upon the success of the PSM2200 and PSM17xx series of frequency response analyzer ranges and combines the experience gained from the design and development of our power analyser range of isolated input channels in order to provide a solution for high voltage, high accuracy, isolated gain, and phase measurement. Utilising an innovative design that incorporates both direct digital analysis and heterodyning techniques within 500Vpk galvanically isolated input/output channels, the PSM3750 provides a broad range of measurement functions over a wider frequency range than any other instrument available today.

As with other N4L products, PSM3750 NumetriQ utilises the latest DSP and FPGA technology to optimise the use of its analogue hardware providing speed and measurement flexibility without compromise on the performance of each measurement function.

control_loop transistor filter audio opto coax ldo transformer cross_talk emi
Control Loop
Filter Design
Audio Amplifier
Coax Cable
LDO Regulator
Signal Transformer
 Cross Talk
 RFI/EMC Filter

Product Images

Features and Benefits

Frequency range 10µHz to 50MHz Isolated inputs – 500 Vpk
 Gain accuracy at < 1 MHz 0.01 dB Phase accuracy at < 1 kHz 0.025°
Frequency response analyzer Impedance analyzer
Vector Volt Meter / Phase Angle Volt Meter RMS Volt Meter / Oscilloscope
Loop response analysis Harmonic analyser

This product is designed and manufactured in the UK. Support is available directly from our UK facility and locally via our US office or network of international distributors. All measurements are traceable to UKAS, certificates of conformance and calibration are supplied as standard. Our products are CE marked.

Brochures  Documentation 
PSM3750_Brochure PDF, 7.7Mb PSM3750 User Manual v3.1 PDF, 679Kb
PSM3750-Dimensions PDF, 90Kb PSM3750 Comms manual v1.20PDF, 495Kb
PSM3750-Rack-Dimensions PDF, 90Kb PSM3750 Start up guide v3.00 PDF, 2,720Kb
PSMComm2 User Manual v1_1c PDF, 2.79Mb LCR Compensation Guide PDF, 165Kb
  IAI2 User Manual PDF, 562Kb


PSM3750 Options, Software and Accessories

COMMS_ICON Communications Interfaces:
  • Standard: RS232, USB, LAN, GPIB
PROBE_ICON Probes and Probe Accessory Options:
INJ_TRANSFORMER_ICON Injection Transformer Options
  • Injection transformers not required as PSM3750 features fully isolated generator
CLAMP_ICON Current Measurement Options:

Impedance measurement can also be performed via external shunts, the IAI2 is not required for this approach to impedance analysis and an LPA power amplifier provides the test signal. Voltage across the DUT is measured with CH1 on the PSM3750 and current through the device is measure with CH2 on the PSM3750 across the N4L HF current shunt.

  • HF010m 10mΩ/20Arms 1MHz Bandwidth Current Shunt
  • HF100m 100mΩ/6Arms 1MHz Bandwidth Current Shunt
  • HF470m 470mΩ/3Arms 1MHz Bandwidth Current Shunt
  • HF01A 1Ω/1Arms 1MHz Bandwidth Current Shunt
EXTENSION_ICON Port Accessory Options:
  • USB to 9 Pin RS232 Serial Converter
CASES_ICON Carry Cases:
  • PSM3750 Soft Carry Case – Black Nylon Padded Case with accessory space, handle and strap
RACK_ICON Rack Mounting Kit Options:
CALIBRATION_ICON Calibration and Documentation:
  • Standard Recalibration – PSM3750
  • Standard Recalibration – PSM3750 + IAI
  • External Laboratory ISO17025 UKAS Calibration + Standard Calibration – PSM3750
  • Spare set of user manuals – Hard copy of user and communications manual
PC_ICON PC Software (Free of charge):
  • PSMComm – PSM PC Interface Software, databasing, graphs, real time data display (PSMComm2 v1_2 PDF, 2.79Mb)
  • PSMSoft – Labview Executable with PSM, including Nyquist Simulation

Application Notes and Related Articles

For application notes please see the app note section of our Knowledge Database

Frequency Response Analyser
Measurement Magnitude, Gain (CH1/CH2, CH2/CH1),
Gain (dB), Offset Gain (dB), Phase (º)
Frequency Range 10µHz – 50MHz
Gain Accuracy in dB 0.01dB + 0.1dB / MHz < 5MHz
0.31dB + 0.04dB / MHz < 50MHz
Phase Accuracy 0.025º < 10kHz
0.05deg + 0.00025deg / kHz < 50MHz
Frequency Source Generator or CH1 Input
Measurement Real Time DFT, no missing data
Speed Up to 100 reading per second
Filter Selectable from 0.2 seconds
Phase Angle Voltmeter
Measurement In Phase, Quadrature, Tan Ø, Magnitude, Phase, In-Phase ratio, rms, rms ratio, LVDT differential, LVDT ratiometric
Frequency Range 10µHz – 50MHz
Basic Accuracy (AC) 0.075% range + 0.075% reading + 50µV < 10kHz
0.075% range + 0.25% + 0.001% / kHz rdg + 50µV < 1MHz
0.075% range + 0.01% + 0.00025% / kHz rdg + 50µV < 50MHz
L C R Meter
Functions L,C,R (AC), Q, Tan Delta, Impedance,
Phase – Series or Parallel Circuit
Frequency Range 10µHz – 50MHz (35MHz - 50MHz reference only)
Current Shunt External or Optional IAI2 Impedance Interface
LCR Measurement Functions
Resistance (R) 1mOhm to 500MOhm
Reactance (X) 1mOhm to 500MOhm
Impedance (Z) 1mOhm to 500MOhm
Capacitance Value (Cp & Cs) 1pF to 1mF
Phase Angle 0 to 360 deg with 0.001 degree resolution
Q. Factor +/- 0.00001 ~ 9999.99
Tan Delta (Reciprocal of Q, also known as Dissipation Factor (D) +/- 0.00001 ~ 9999.99
Admittance (Y) reciprocal of impedance (Siemens) +/- 2nS to 1KS
Conductance (G) resistive part of admittance (Siemens) +/- 2nS to 1KS
Susceptance (B) reactive part of admittance (Siemens) +/- 2nS to 1KS
Voltage Bias +/- 10V
Ranges (External Shunt) Inductance 1H to 100 H
Capacitance 100pF to 100F
Resistance 1Ω to 1MΩ
Basic Accuracy 0.1% + Tolerance of Shunt
Sweep Capability all AC functions
True RMS Voltmeter
Channels 2 (Optional 3rd Channel Available)
Frequency Range DC to 5MHz
5MHz to 50MHz fundamental only
Measurement RMS, AC, DC, PEAK, CF, SURGE, dBm
Basic Accuracy (AC) As PAV + 0.05mV
Basic Accuracy (DC) 0.1% range + 0.1% reading + 0.5mV
Power Meter
Measurements W, VA, PF, V, A, Total, Fundamental and Integrated, Power Harmonics
Frequency Range DC to 5MHz
5MHz to 50MHz fundamental only
Current Shunt External
Current Accuracy As Voltage + External Shunt Tolerance
Watts Accuracy 0.1% VA range + 0.1% reading + External Shunt Tolerance
Signal Generator
Type Fully isolated 10Vrms output protected to 500Vpk, Direct Digital Synthesis
Frequency 10µHz – 50MHz
Waveforms Sine, Square, Triangle, Sawtooth, White Noise
Accuracy (no trim) Frequency 0.05%
Amplitude ±5% < 10MHz,
Amplitude ± 10% < 50MHz
Impedance 50 Ohm ± 2%
100pF to Chassis
Output Level
(Open Circuit)
35mVrms to 10Vrms
Offset ±10vdc, Resolution 20mV
Harmonic Analyser
Scan Single or Series
Frequency range 20mHz to 5MHz
5MHz to 50MHz Fundamental only
Measurement Harmonic, Series, THD, Difference THD
Max Harmonic 100
Input Ranges
Differential Inputs 2 or 3 x Isolated Inputs 500Vpk
Connectors Isolated BNC
Coupling AC+DC, AC (<10VDC), AC (< 500VDC)
Ranges 3mV, 10mV, 30mV, 100mV, 300mV, 1V,
3V, 10V, 30V, 100V, 300V, 500V,

300mV∗, 1V∗, 3V∗, 10V∗
∗ High Voltage Attenuator

Scaling 1 x 10^-9 to 1 x 10^9
Ranging Full auto, Up only or Manual
Input Impedance 1M Ohm Differential / 100pF to Chassis
Model Numbers
Available Packages
PSM3750 – 2C

PSM3750 – 3C

PSM3750 – 2C + IAI2

PSM3750 – 3C + IAI2

2 Channel PSM3750

3 Channel PSM3750

2 Channel PSM3750 + IAI2

3 Channel PSM3750 + IAI2

IAI2 – Impedance Analysis Interface
Frequency Range 10µHz – 50MHz
Measurement Parameters L, C, R, Z, Phase, QF, Tan (δ), Series and Parallel Circuit
Basic Accuracy 0.1% 1kHz
0.2% + 0.002% / kHz < 1MHz
0.2% + 0.0005% / kHz < 35MHz
0.2% + 0.001% / kHz < 50MHz
Measurement Ranges 10nH to 10kH, 1pF to 1000F,
1mΩ to 500MΩ
Phase Accuracy of Internal Shunts Low Shunt 5Ω, 0.1deg + 0.01deg / kHZ
Medium Shunt 50Ω, 0.05deg + 0.005deg / kHz
High Shunt 5kΩ, 0.05deg + 0.005deg / kHz
Very High Shunt 500kΩ 0.1deg + 0.05deg / kHz
Accessories and Ports
Probes 4 off with 2 Channel Version.
6 off with 3 Channel Version
Leads Output, RS232, Power
Software CommView, PSMComm2
Documentation Calibration Certificate, User Manual
RS232 Baud Rate to 19200, RTS/CTS flow control
Analog Output Bipolar ±10V on any measured function – BNC
Sync Output Pulse Synchronised to Generator
Extension Ports

(N4L Accessories)


15 pin female D type

LAN (Standard) 10 / 100 base-T Ethernet auto sensing RJ45
GPIB (Standard) IEEE488.2 Compatible
System Specifications
Functions Up to 4 measured functions, User Selectable
Datalog Window From 10mS with No Gap between each log
Memory RAM or Non Volatile Memory up to 16,000 records
Display 320 x 240 QVGA full colour TFT, White LED backlit
Dimensions 130H x 400w X 315D mm excluding feet
Weight 3.3kg (2Channel), 3.5kg (3 Channel)
Program Stores 100, Location 1 Loaded upon Power Up
Sweep Stores 2000, all parameters in any sweep function
Remote Operation Full Capability, Control and Data
Operating Temperature -5 to 50°C
Storage Temperature -10 to 60°C
Relative Humidity Range 20 to 90% Non-Condensing
IP Protection of Inputs and Outputs IP30 - CEI EN 60529
Max Altitude 2,000 Metres
Power Supply 90-264Vrms 47-63Hz 30VA max
CMRR 140db @ 240Vrms – 50Hz, 120db @ 100Vrms – 1kHz
Warranty 3 Years