Model Explanation

PXI: PXI bus standard (PCI eXtensions for Instrumentation)

2558: Product serial number, specifically referring to four sets of SPDT 75Ω RF relay modules

Full Name: PXI-2558 / 778572-58 → 2.5 GHz 75Ω Quad SPDT Relay Module

Topology Alias: NISWITCH_TOPOLOGY_2558_4_SPDT Technical Specifications

RF Performance

Bandwidth: DC～2.5 GHz

Characteristic Impedance: 75 Ω (suitable for video / CATV)

Terminal Matching: No built-in terminal (external matching)

Insertion Loss: ≤ 0.8 dB @ 2.5 GHz

VSWR: ≤ 1.8:1 @ 2.5 GHz

Channel Isolation: ≥ 50 dB @ 2.5 GHz

Switching and Electrical

Topology: Four sets of SPDT (Quad SPDT), 4 independent channels, each with 1 common terminal (COM), 1 normally open (NO), 1 normally closed (NC)

Relay Type: RF latching relay

Maximum Switching Voltage: 30 V

Maximum Channel Current: 0.5 A (per channel)

Maximum RF Power: 5 W (25°C)

Relay Life: ≥ 10⁶ times (typical value)

Control Interface: PXI bus (NI-SWITCH driver)

Physical and Environmental

Size: Standard PXI 3U single slot

Weight: Approximately 0.45 kg

Connectors: Front panel 12×BNC (4×COM, 4×NO, 4×NC)

Operating Temperature: 0～55°C

Storage Temperature: -40～70°C

Interface and Communication Configuration

Front panel interface

CH1～CH4: Each channel contains COM (common terminal), NO (normally open), NC (normally closed), a total of 12 BNC, all 75Ω

Impedance: 75Ω, no built-in terminal, external matching required

Backplane and Control

PXI backplane: 3U single slot, compatible with PXI-1/PXIe mixed slots

Power Supply: PXI backplane ±15 V, 5 V power supply

Trigger: Supports PXI TTL0～TTL4 hardware trigger, software immediate trigger

Driver: NI-SWITCH, supports LabVIEW, TestStand, CVI

Core Function

4 independent SPDT RF switching: Each channel can independently switch COM→NO or COM→NC, flexible routing

75Ω wideband signal transmission: DC～2.5 GHz, suitable for video / CATV / RF component testing

Flexible topology expansion: Can be cascaded to build large matrices or multi-channel multiplexers, maintaining consistent paths

Relay Life Tracking: Board-mounted counter, predictive maintenance, reducing downtime

PXI Plug-and-Play: Standard driver, quick integration into automated test systems Applicable scenarios

Video / Cable Television (CATV) signal switching: Multi-channel video routing, distribution and switching

RF component testing: Amplifiers, filters, attenuators - input/output switching and path control

Aerospace / Defense: Multi-channel RF signal routing, satellite communication equipment testing

Semiconductor testing: RF chips, transceivers - signal path configuration

Industrial ATE: Production electronic products RF / video function testing, building custom switch matrix

User and maintenance instructions

Installation and configuration

Insert the PXI 3U single slot and fix the panel

Install the NI-SWITCH driver, identify the hardware

Configure the topology as 4-SPDT

Connect BNC cables, avoid excessive force bending; externally, connect a 75Ω terminal to prevent reflection

Key operation points

RF power limitation: Single-channel RF power ≤ 5 W at 25°C, temperature reduction for high temperatures

Avoid static electricity: Ground before operation to prevent RF relays from being damaged by static electricity

Trigger method: Software immediate trigger or PXI TTL hardware trigger, synchronize test process

Independent control: 4 SPDT can be independently controlled, not interfering with each other

Maintenance and calibration

Life monitoring: Read the number of relay closures through NI-SWITCH, an alarm is triggered when it reaches 10⁶ times

Regular calibration: Calibrate insertion loss, VSWR, isolation every year to ensure test accuracy

Environmental requirements: Operating temperature 0～55°C, humidity 10%～90% (no condensation)

Storage: -40～70°C, dry and dust-free, clean connectors before long-term storage