Test Overview/Procedures

To make PARD measurements, the electronic load used should operate in CR mode for constant volt- age and constant current power supplies. The load should also have lower PARD than the power sup- ply being tested. This is especially important when measuring the PARD of linear power supplies, since they typically have excellent PARD specifications.

A regulated AC source should be applied to the input of the power supply under test. PARD meas- urements are made at the lowest and highest speci- fied values of AC input to the power supply, and at the lowest and highest specified source frequencies.

Proper connections between the instruments and power supply under test are essential when making these measurements. Since PARD consists of low level, broadband signals, major test set concerns are ground loops, proper shielding, and impedance matching. A digitizing oscilloscope can be used for peak-to-peak measurements (see Figure 8). High frequency noise spikes need to be measured, and therefore the digitizing rate of the oscilloscope must be at least five times the maximum PARD frequen- cy for proper sampling. To eliminate cable ringing and standing waves, the typical configuration includes coaxial cabling with 50 Ohm terminations at both ends. Capacitors should be connected in series with the signal path to block the DC current.

A true rms RF voltmeter should be used to meas- ure the rms specification. Precautions similar to those for the peak-to-peak measurements should be considered. For both measurements, care should be taken to prevent ground loops. Since most oscilloscopes and true rms voltmeters have ground referenced inputs, testing a power supply with grounded outputs may create such a ground loop. In this case, it may be necessary to use instru- ments with floating (differential amplifier) inputs to eliminate this problem.

The first set of PARD measurements should be made with the AC source voltage and frequency set at the lowest specified values, and with the power supply under test at its minimum and then maximum rated load value. A second set of meas- urements should be made with the AC source set at the highest specified values of amplitude and frequency, and with the power supply minimally loaded and then maximally loaded. To test multiple output power supplies, PARD measurements for each output should be made with all other outputs set initially to minimum load, and then to maxi- mum load.

Figure 8. PARD Testing Configuration

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Agilent Technologies AN 372-1 specifications Pard Testing Configuration
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AN 372-1 specifications

Agilent Technologies AN 372-1 is a versatile and highly regarded instrument in the field of electronic testing and measurement. Designed primarily for research and development, as well as validation in production environments, this advanced technology showcases Agilent's commitment to providing high-quality measurement solutions.

One of the standout features of the AN 372-1 is its wide frequency range capability, enabling it to effectively measure signals across various applications. This instrument supports a frequency range extending up to 26.5 GHz, making it suitable for high-frequency applications in telecommunications, aerospace, and defense sectors. With this broad frequency capability, users can rely on the AN 372-1 for accurate and reliable measurements in the most demanding environments.

Another significant attribute of the AN 372-1 is its high dynamic range, which allows for precise detection of both weak and strong signals in the presence of noise. This characteristic is essential for engineers working to ensure signal integrity in complex systems, as it allows for the identification of issues that may otherwise go unnoticed. Coupled with a fast sweep speed, the device can quickly capture transient events or changes in signals, making it a vital tool for time-sensitive applications.

The user interface of the AN 372-1 is designed for ease of use, with a touchscreen display that simplifies interaction and data visualization. Its intuitive design enables users to set up measurements and navigate through the many options effortlessly. Furthermore, the instrument is equipped with advanced analysis features and software that enhance data interpretation and manipulation, allowing engineers to derive meaningful insights from their measurements quickly.

In addition to its measurement capabilities, the AN 372-1 supports advanced connectivity options, including USB, LAN, and GPIB. This ensures seamless integration with other instruments and systems, facilitating a more streamlined testing workflow. The ability to connect with external software also enhances its functionality, allowing users to automate processes and improve test efficiency.

The AN 372-1's rugged design ensures it can withstand the challenges of both laboratory and field use. Its build quality speaks to Agilent's commitment to creating long-lasting instruments that offer reliable performance throughout their lifecycle. Overall, the Agilent Technologies AN 372-1 stands out as a comprehensive tool for engineers and researchers requiring precise, reliable, and efficient electronic measurements across a myriad of applications.
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