II. Model Interpretation

PXI: Compliant with the PXI bus standard, compatible with PXIe hybrid slots

2554: The serial number of the NI RF multiplexer series, representing 2.5 GHz, 75 Ω, 4×1 (SP4T), electromechanical relays

Alias: NI-2554, 4×1 Mux, SP4T RF Switch, 75 Ω Video Multiplexer

Position: 75 Ω dedicated, 4-out-of-1 RF multiplexer, suitable for broadcasting / video RF scenarios, single-slot high-density integration.

III. Technical Parameters Basic parameters

Topology: 4×1 multiplexer (SP4T), 4 input channels (CH1 to CH4) switched to 1 common output channel (COM) NI

Relay type: Electromechanical latch relay (EMR)

Frequency range: DC to 2.5 GHz (–3 dB)

Characteristic impedance: 75 Ω (nominal)

Channel configuration: 1 bank, 4 input channels, 1 output channel

RF performance (typical / guaranteed values)

Insertion loss:

≤1 GHz: <0.8 dB (typical <0.5 dB)

≤2 GHz: <1.3 dB (typical <0.9 dB)

≤2.5 GHz: <1.7 dB (typical <1.2 dB)

Channel-to-channel isolation NI:

≤1 GHz: >47 dB

≤2 GHz: >40 dB

≤2.5 GHz: >40 dB

VSWR:

≤2.5 GHz: <1.75 (typical <1.5)

Maximum switching power: 10 W (continuous) NI

Propagation delay: typical 1.0 ns NI

Rise time (10%–90%): typical 75 ps NI

Channel skew: typical <25 ps NI

Electrical and dynamic

Maximum switching voltage: 30 VDC NI

Maximum switching current: 0.5 A (per channel) NI

Maximum carrying current: 0.5 A (per channel) NI

Switching time: maximum 10.4 ms NI

Relay lifespan NI:

Mechanical lifespan: 1×10⁶ times

Electrical lifespan (30 V, 10 mA, DC resistive): 3×10⁵ times

Scan rate: maximum approximately 95 times/second

Physical and environment

I/O connector: 5×SMA female (4×CH + 1×COM, gold-plated)

Size: 3U PXI single slot (21.6 × 2.0 × 13.0 cm)

Weight: approximately 204 g

Power consumption: 12 V ≈ 0.4 W

Operating temperature: 0 to 55 °C

Storage temperature: –20 to 70 °C

Relative humidity: 5% to 85%, no condensation

IV. Interface and communication configuration

Front-end interface

RF interface: 5×SMA female

CH1 to CH4: 4 RF input channels (75 Ω)

COM: common output terminal (75 Ω)

Trigger interface: PXI backplane trigger line 0 to 7, minimum pulse width 150 ns NI

Bus and control

Bus interface: standard 3U PXI mixed bus (compatible with PXIe mixed slot)

Control software: compatible with NI- SWITCH, MAX, LabVIEW, TestStand, Switch Executive

Driver support: IVI compatible driver, provides LabVIEW VI and text language API

Trigger synchronization: PXI hardware trigger, multi-module cascading synchronization

Configuration method: software selects any one of the 4 channels to connect to COM, supports single-step switching and sequential scanning

Adaptation and expansion

Adaptation cable: SMA-SMA (75 Ω); optional SMA to BNC (75 Ω)

Expansion capability: multi-module cascading, builds N×1 multiplexer or 4×N matrix

V. Core functions

4×1 multiplexer (SP4T): 4 75 Ω RF signals selected to a single COM, realizes multi DUT / instrument sharing of a single port, simplifies test topology. DC - 2.5 GHz Broadband Coverage: Covers CATV (5 - 1000 MHz), satellite intermediate frequency, high-definition video, and ISM frequency bands, suitable for mainstream 75 Ω RF applications.

75 Ω Precise Impedance Matching: The entire system is designed with 75 Ω, eliminating impedance mismatch reflections, protecting the 75 Ω source end and DUT, and improving test accuracy.

Low Loss + High Isolation + Excellent VSWR: Low insertion loss, high channel isolation, small standing wave ratio, minimizing signal attenuation and crosstalk.

Relay Life Monitoring: On-board counter tracks the number of each channel switch, predicting lifespan, reducing unplanned downtime.

PXI Standard Integration + Low Power Consumption: Single slot 3U size, seamless integration into PXI chassis; latch relay design, no continuous power supply after switching, low heat generation.

Six, Application Scenarios

CATV / Broadcasting Equipment Testing: Multi-channel switching and parameter testing for 75 Ω RF ports of set-top boxes, modulators, amplifiers, distributors, etc.

Video RF Signal Routing: Selective routing and distribution of high-definition video, satellite intermediate frequency, and monitoring RF signals, preventing reflection damage to the source end.

75 Ω RF Component Verification: Function and mass production testing of filters, mixers, attenuators, antennas, etc., 75 Ω components.

Parallel Testing of Multiple DUTs: 4 75 Ω DUTs share one instrument (spectrum analyzer / network analyzer), improving test efficiency.

Research and Development Laboratory and Scheme Verification: Debugging, matching test of 75 Ω RF links, multiple scheme comparison, low reflection to ensure accuracy.

Seven, Usage and Maintenance Instructions

Usage Tips

Installation: Standard 3U PXI single slot, lock the panel, ensure reliable contact of the backplane; avoid strong vibration and electromagnetic interference.

Connection: SMA connector is lightly inserted and removed; RF power ≤ 10 W (continuous),严禁 exceeding power； unused ports are recommended to be connected to 75 Ω terminators.

Power On Status： Default no channel connection (COM open)， need software to specify CHx → COM connection.

Software Control： Use NI-SWITCH or LabVIEW VI to select channels； regularly read relay counters to monitor remaining lifespan.

Environment： 0 - 55 °C operation， dust-proof， moisture-proof， and dew-proof； away from strong electromagnetic interference， ensure good grounding.

Maintenance Instructions

Regular Inspection： Quarterly inspection of SMA connectors for looseness， oxidation， or damage； clean the panel and ventilation ports， maintain good heat dissipation.

Life Management： Mechanical life is approximately 1 million times； regularly read onboard counters， plan for replacement in advance to avoid downtime.

Fault Troubleshooting： First check SMA connection， 75 Ω terminators and grounding； use MAX diagnostic switch status； take precautions against static electricity.

Storage： Power off when not in use， cover SMA with dust cap， dry and dust-proof storage， avoid high temperature， high humidity and strong magnetic fields.

Calibration： Suggested to calibrate once a year to ensure insertion loss， isolation， VSWR， etc.， meet specifications； can contact NI or third-party calibration institutions.