Introduction to the method of preventing spectrum analyzer damage by Antai maintenance

A spectrum analyzer is an instrument for studying the spectral structure of electrical signals. It is used to measure signal parameters such as signal distortion, modulation, spectral purity, frequency stability, and intermodulation distortion. It can be used to measure certain parameters of circuit systems such as amplifiers and filters. It is a multi-purpose electronic measuring instrument.

So how to prevent the damage of spectrum analyzer? Let's learn with Antai Maintenance Huagong:

1. Ensure proper grounding

1. Always use the three-phase AC power cord that comes with the analyzer.
2. Properly ground the instrument to prevent static charge accumulation. The accumulation of large amounts of static charge may cause damage to the instrument and personal injury to the operator.
3. Do not use extension cables, power cords, or autotransformers without a protective grounding conductor to avoid damaging the grounding protection.
4. Check the quality and polarity of the AC power supply; the AC voltages typically required are 100 V, 120 V, 220 V ±10%, or 240 V + 5%/-10%. Typically, the expected ground wire resistance is < 1 Ω, and the voltage between neutral and ground is < 1V. Install an uninterruptible power supply [UPS] if necessary.

2. Read warning labels and technical specifications

1. Do not exceed the parameter values ​​given in the Specifications Guide or the values ​​indicated by the yellow warning label on the analyzer.
2. Refer to the Specifications Guide for conditions required to achieve the listed specifications. Note the information on stabilization time, instrument setup, and calibration requirements.
3. For example, the yellow warning label on the front panel of the E4440A PSA indicates that the maximum RF input power applicable is 30 dBm (1W) and 0 Vdc DC coupled voltage or 100 Vdc AC coupled voltage.

3. Avoid inputting too much power to the analyzer

1. Limit the signal level to be measured with the spectrum analyzer to avoid damage to the front end. Applying too much power to the front end may cause damage to the front end components. The typical maximum RF input signal level is 30dBm (1W).
2. Turn off the DUT/signal source or reduce the power of the DUT/signal source before turning on or off the connected device or DUT. This helps prevent unexpected voltage increases or decreases and avoids affecting the input or output of the analyzer. Use DC blocks, limiters, or external attenuators as needed.

For example,
①Keysight 11867A RF limiter can provide input protection. It will reflect signals with average power up to 10 W and peak power up to 100 W. In many spectrum analyzer applications, 11867A can provide input protection for attenuators and mixers that meet the specified frequency range.
②11742A DC blocking capacitors can block DC signals below 45 MHz and allow signals up to 26.5GHz to pass. It is ideal for use with high frequency oscilloscopes or in biased microwave circuits to suppress low frequency signals that could damage expensive measurement instrumentation.

4. Protect the RF input connector

1. Be careful not to bend, bump, or fold any device under test (DUT) connected to the analyzer input, such as filters, attenuators, or long cables. This will reduce the strain on the input connector and installed hardware.
2. Make sure the input properly supports external connected devices (rather than leaving them hanging).
3. Do not mix 50Ω and 75Ω connectors and cables.

5. Use RF cables and connectors correctly

1. Avoid bending cables repeatedly. Bending at too sharp an angle can damage the cable immediately.
2. Limit the number of connections and disconnections to reduce wear and tear.
3. Inspect connectors before using them; check for dirt, cracks, and other signs of damage or wear. A faulty connector can quickly cause a good connector to fail.
4. Always use a torque wrench and gauge tool to connect RF connectors.
5. Clean dirty connectors to avoid affecting the electrical performance of the connection or damaging the connection.

6. Correctly prevent electrostatic discharge

1. Electrostatic discharge (ESD) may damage or destroy electronic components. Therefore, testing should be performed at an anti-static workstation as much as possible. Keep all components at least 1 meter away from materials that may generate static electricity. Before connecting the coaxial cable to the analyzer, short-circuit the center and outer conductors of the cable together to ground.
2. Install ESD protective covers on all RF connectors before transporting and moving equipment.

7. Maintain proper ventilation and humidity conditions

1. Check and clean the ventilation holes of the instrument regularly. Poor air circulation may cause the instrument to overheat and malfunction. The optimal operating temperature of the instrument is 20°C to 30°C.
2. When installing the product in the chassis, the air convection channel in and out of the instrument must not be blocked. For every 100 W of power consumed by the chassis, the ambient temperature must be 4°C lower than the maximum operating temperature of the product. If the total power consumption of the chassis is greater than 800 W, forced ventilation must be used.

8. Use the correct method of movement

1. When transporting the instrument, hold the handle tightly to lift it.
2. Avoid lifting the instrument by grasping the front panel directly. If the instrument slips, the keyboard, knobs, or input connectors may be damaged.
3. Use a cart or two people to help move heavy instruments. Properly package the instrument for transportation.
4. Using unspecified packaging materials may cause damage to the instrument. Do not use styrene beads of any shape as packaging materials. They do not provide adequate cushioning for the device and may generate static electricity, causing damage to the device. Try to keep the original packaging so that it can be reused when transporting the instrument.

9. Change instrument settings

1. Before taking any measurements, first review the measurement procedures and settings required for the particular application (see Measurement Guide).
2. Depending on the type of repair, the analyzer settings may have to be restored to factory settings.