Teseq ISN T4A Impedance Stabilization Network (ISN) for Unscreened Balanced Pairs

Impedance stabilization networks (ISN, or with CISPR 16-1-2 called AAN: asymmetric artificial network) are defined for measuring of conducted common mode disturbances at information technology equipment (ITE) as required in CISPR 22 and CISPR 32. The ISN is placed between the equipment under test (EUT) and auxiliary equipment (AE) or load which are necessary for the operation of the EUT. The ISN establishes the common-mode termination impedance for the EUT’s telecommunications port during measurement and emulates the unsymmetrical contribution (longitudinal conversion loss, LCL) of the connected line. Different ISNs are available in relation to the line category, line numbers and pin-arrangement.

The ISN T4A is designed for measurements on one or two unscreened balanced pairs and consists of one basic network (ISN T400A) with D sub 25 connectors and special adapter sets. A set of adapters consists of LCL adapters to realize the longitudinal conversion loss (LCL)- requirements for the EUT-side in relation to the used cable category (cat. 3, cat. 5) and a connection adapter for the AE-side.

Features & Specifications of Teseq ISN T4A:

• Frequency range: 150 kHz to 80 MHz
• Line parameters: 1 or 2 pairs

Power rating (EUT and AE port)

• AC max. voltage (line to ground): 63 V
• DC max. voltage (line to ground): 100 V
• Current max.: 600 mA (line), 1200 mA (pair)
• Test voltage: 200 VDC, 2 sec

Common mode impedance (EUT port)

• 150 kHz to 30 MHz: 150 Ω ±20 Ω
• 30 MHz to 80 MHz: 150 Ω ±40 Ω
• Phase angle (EUT port) 150 kHz to 30 MHz: 0° ±20°

Coupling path (In/Out port/EUT)

• Connection: BNC 50 Ω
• RF voltage: <15 V
• Frequency range: 150 kHz to 80 MHz

Voltage division factor (RF input to EUT port)

• 150 kHz to 30 MHz: 9.5 dB ±1 dB
• 30 MHz to 80 MHz: 9.5 dB ±2 dB
• Transmission bandwidth* (wanted signal) EUT/AE B3 dB: > 100 MHz sin.

LCL (EUT) *)

• Cat. 3 150 kHz to 30 MHz (corner frequency 2 MHz): 55 dB to 39.3 dB ±3 dB
• Cat. 5 150 kHz to 2 MHz: 65 dB ±3 dB
• Cat. 5 2 MHz to 30 MHz: 65 dB to 49.3 dB +4.5/-3 dB

Decoupling of common mode disturbances (EUT/AE)

• 150 kHz to 1.5 MHz /30 MHz: ≥35 dB to ≥55 dB/≥55 dB
• Crosstalk (PSELFEXT) (EUT /AE) 1 MHz to 100 MHz: ≥61 dB to ≥21 dB

*) all balanced parameters are in relation to a symmetrical load of 100 Ω