Frequency Response Analyzer Accessories

The N4L range of frequency response analyzers can be used in a wide range of applications, in reflection of this we have developed various accessories to enable accurate, reliable and convenient measurement.

Injection Transformers

N4L Injection Transformers –  Feedback Loop Response Analysis
LFIM Frequency Response Analyzer Injection Transformer

The PSM1700 and PSM1735 feature ground referenced generators, as a result there is a requirement to isolate the injected perturbation signal from ground so that the feedback loop is not shorted to the ground plane.  This action is performed by an injection transformer and N4L have designed numerous injection transformers to meet a range of frequencies and voltages.

Model   Frequency Range    Voltage Rating    Turns Ratio   Connectors 
Standard Injection Transformer 10Hz to 200kHz 50V 6.3:1 BNC Input, Isolated BNC Output
HF Injection Transformer 500Hz to 35MHz 50V 2.3:1 BNC Input, Isolated BNC Output
HV Injection Transformer 5Hz to 15MHz 1KV CATII 2.3:1 BNC Input, 2x 4mm Safety Connector Output
Low Frequency Injection Module DC to 100kHz 600V CATII 3.1:1 BNC Input, 2x 4mm Safety Connector Output

Specification Data
PSM Injection Transformer Range – Datasheet

LCR Measurement

IAI Kelvin Fixture
Impedance Analysis LCR Kelvin Fixture

The N4L Impedance Analyzer range offers high accuracy, high frequency LCR measurement. To accompany the IAI and IAI2 we have developed an IAI Kelvin Fixture. This fixture features four contact plates providing true four wire impedance measurement.

Frequency Range
DC to 35MHz


 BATT470m – EIS Interface (Electrochemical Impedance Spectroscopy)
batt470m_350px The BATT470m electrochemical impedance analysis interface (EIS) provides an easy to use battery/cell impedance test platform for the electrochemical industry. Utilizing the highly accurate PSM3750 frequency response analyzer from N4L, the BATT470 provides impedance measurement of batteries/cells up to 200V DC.

Frequency Range Accuracy Impedance Range Voltage Rating
100mHz to 1MHz 0.1% typical 1mOhm to 1kOhm 200V

Specification Data
Batt470m EIS Interface – Datasheet



N4L ESF External Signal Filters
N4L ESF Filters are a range of filters specifically designed for use with the N4L range of HF current shunts.
Available as 5 kHz low pass and 50 kHz low pass for improved signal to noise ratio.
These compact filters are fitted with safety BNC connectors to enable direct connection to the PPA external inputs.
The ESF10m filter has been designed for DC blocking and is designed to be used in pairs with our BATT470m EIS (Electrochemical Impedance Spectroscopy)

Model Roll off Frequency
-3dB@ 5kHz ± 1kHz
-3dB@ 50kHz ± 10kHz
-3dB@ 10mHz ± 2mHz
Specification Data
ESF Filters – Datasheet

Current Measurement

 N4L HFR High Frequency Current Shunts
Frequency Response Analyzer Current Shunts

If external current measurement is necessary for impedance measurement, for example if a test setup utilising an LPA Laboratory Power Amplifier for signal generation is employed. The HF series shunts provide an accurate current sensing solution for many wideband measurement applications up to 20Arms. Utilising an innovative design that is unique to N4L, each shunt will maintain its specified resistance over a frequency range from DC to 1MHz without exhibiting the phase shift normally associated with resistive shunts.

Model  Current Rating
HFR010 20Arms
HFR100 6Arms
HFR470 3Arms
HF01R 1 Arms
Specification Data
HFR Shunts – PSM – Datasheet


Other models available upon request

AC Current Clamps
AC Current Clamp 1000Arms 15kHz Bandwidth

As an alternative to selecting an HFm current shunt for external current measurement in impedance applications is our AC Current Clamp range. These clamps provide current measurement up to 3,000A (P32-UE) with an upper bandwidth of 15kHz (SMUB), providing accurate measurement of an AC signal over a wide bandwidth. Typical applications include impedance measurement of electrochemical cells where high DC current bias is present, the AC responding current clamp will reject the DC bias current and reliable accurate measurement of the AC perturbation current is recorded.

Model Current Rating
M3-UB-50 100mA → 50A
M3-U-100 1 → 100A
S-UE-200 1 → 200A
S-UE-250 1 → 250/500/1000A
US-UE-1000 1 → 1,000A
SM-UE-1000 0.5 → 1,000A
SM-UB-1000 0.5 → 1,000A
P32-UE-1000 5 → 1,000A
P32-UE-3000 5 → 3,000A
Specification Data
M3 UB 50 – 1V – Datasheet
M3 U 100 – 1V – Datasheet
S UE 200 – 1V – Datasheet
S UE 250 500 1000 – Datasheet
US UE 1000 – 1V – Datasheet
SM UE 1000 – 1V – Datasheet
SM UB 1000 – 1V – Datasheet
P32 UE 1000 – 1V – Datasheet
P32 UE 3000 -1V – Datasheet

Other models available upon request

High Voltage Measurement

TT-HV-250 High Voltage Probe (2.5kVpk)
TT-HV-250 Power Analyzer Probe

For High voltage applications, we recommend the PSM3750 frequency response analyzer, for voltages above this level an attenuator is required and the TT-HV-250 provides measurement up to 2.5kV.

Voltage Rating Attenuation Bandwidth
2.5kVpk 100:1 300MHz
Specification Data
N4L 2.5KV High Voltage Probe x100 – Datasheet



Other models available upon request

TT-HVP-15HF High Voltage Probe (15kVpk, 10kVrms)
TT HVP 15HF Power Analyzer Probe 15kV

The TTV-HVP-15HF High Voltage Probe provides 1000:1 attenuation of voltages up to 15kV, with a bandwidth of 50MHz these probes provide high voltage accurate measurement. For connection advice please contact the N4L application engineering department.

Voltage Rating Attenuation Bandwidth
15kVpk, 10kVrms 1000:1 50MHz
Specification Data
15KV High Voltage Probe x1000 – Datasheet


Other models available upon request

ULCP Ultra Low Capacitance Probe (1kVrms)
ULCP ULtra Low Capacitance Probe

The ULCP ultra low capacitance probe is intended for voltage measurement of devices which are particularly sensitive to capacitive loading. This is particularly useful when measuring start up characteristics of low power lighting ballasts, the ULCP Ultra Low Capacitance Probe utilises a differential input design that provides a capacitance to ground of 1pF.

Voltage Rating Attenuation Bandwidth
3kVpk, 1kVrms 1000:1 2MHz
Specification Data
ULCP – Ultra Low Capacitance Probe – Datasheet



Other models available upon request

19in Rack Mount Kits

PSM17xx Rack Mount Kit
frequency response analyzer 19 inch rack mount kit

The PSM1700 rack mount kit provides a convenient, neat method of integrating the PSM1700/PSM1735 Frequency Response Analyzers into a 19in rack. The rack mount kit consists of a framing plate.

Height Compliance
4U EIA Standard


PSM3750 Rack Mount Kit
Power Analyzer 19in Rack Mounting Brackets

The PSM3750 rack mount kit consists of two 19in rack mounting brackets providing simple integration into any EIA standard 19in rack system. The brackets are fitted to the Frequency Response Analyzer by removing the two handle fixtures situated on each side of the instrument.

Height Compliance
4U EIA Standard



ATT Series Attenuators
N4L ATT20 20:1 Attenuator

The ATT10, ATT20 and ATT1000 are BNC to BNC voltage attenuators designed for the PSM BNC inputs. They provide high accuracy wide bandwidth gain, typical applications are in situations when the output of a voltage attenuator (such as the TT-HV250) is above the 10Vpk range of the PSM1735 input.

Model  Attenuation Bandwidth Max Input Voltage
ATT10 10:1 DC-2MHz 30Vpk
ATT20 20:1 DC-2MHz 60Vpk
ATT1000 1000:1 DC-10kHz 1000Vrms
Specification Data
ATT10 – Datasheet
ATT20 – Datasheet