Answer to Question #205354 in Electrical Engineering for Bahawal Tahir

Question

what do you understand by network analyzer? write detail note on its working,functionality,applications and specification of network analyzer? (b) what is pNA network analyzer? draw and explain block doagram of network analyzer system? enumerate the difference between network analyzer and spectrum analyzer?what si best network analyzer?

Answer 1

Part a

A network analyzer is a tool for determining the network characteristics of electrical networks. Network analyzers are frequently used to assess two-port networks like amplifiers and filters, but they may also assess networks with any number of ports.

Network analyzers are essential to test instruments in RF design labs and many other industrial and service environments.

Network analyzers can provide critical insights into the operation and performance of RF networks of all sorts, despite their primary concentration on research and development.

The RF network analyzer gives the network a stimulus and then measures its reaction. This allows the operation and performance to be observed and evaluated for appropriateness.

All RF and microwave frequencies can be analyzed using RF network analyzers, and some network analyzers can even function in the microwave range.

The Network Analyzer includes a source for generating a known stimulus signal and a collection of receivers for determining changes in the stimulus induced by the device-under-test (DUT). The receivers on the Vector Network Analyzer take the generated signals and compare them to a known stimulus signal.

The frequency range is the most important characteristic. The frequency range of a network analyzer specifies the minimum and greatest frequencies it can measure. The frequency range of the vector network analyzer is crucial since measurements outside of this range will be impossible.

When deciding on the frequency range for the RF network analyzer, keep in mind that you'll need to test the network's performance at not only the fundamental frequency but also harmonics to see how the network responds at these frequencies - this is especially important for items like amplifiers, mixers, and converters, where harmonic performance is a major factor.

Dynamic range: Another critical parameter is the VNA dynamic range, which specifies the power range in which the RF network analyzer will operate. This might be critical when there is a substantial difference between the highest and minimum power levels involved in measurement. This VNA standard should be at least 6 dB better than the item under test's expected maximum attenuation.

Most mainstream vector network analyzers have dynamic range parameters above 120dB, usually more than enough for all but the most stringent needs. 

Part b

The PNA Series of network analyzers provides industry-leading performance for quickly and precisely evaluating amplifiers, mixers, and frequency converters. Pulsed S-parameter measurements are made possible by built-in pulse modulators and pulse generators—measure S-parameters with the least amount of uncertainty and the most consistency.

Above is a block diagram of a basic two-port vector network analyzer. This diagram depicts the high-level components required for a standard VNA.

Precision connections are located on the front panel of the VNA, and precision cables are used to connect them to the item being tested. Because the phase and loss of a normal cable would fluctuate too much with even minor movement, precision cables are necessary.

A variable frequency signal is created within the vector network analyzer to test the device, and the output is switched to test the DUT in either direction. The left-hand side of the figure is picked in this situation. The signal is divided, and one output is utilized as the receiver's reference signal. At the same time, the other is transmitted to a directional coupler and then into the DUT through the VNA's external connection and precision cables.

The DUT receives power via the directional coupler (directional coupler 1), but the reflected power is detected by the third port, which is then linked to the receiver once again.

Directional coupler 2 samples the power that goes through the item under examination, and this signal is transferred to the receiver.

The signal source has an output that is linked to the receiver and creates a signal to power the item being tested. This makes it possible to extract phase information from observed signals. Currently, vector network analyzers will require a lot of digital signal processing, and a lot of the receiver and detector sections will be done digitally.

The receiver processes the signals before sending them to the processor and displays them. This section will rely heavily on microprocessor technology to offer the control, functionality, and user-friendly displays that modern test equipment requires.

Although this example of an RF network analyzer only has two ports, other vector network analyzers may have more ports for systems with many signal pathways.

Test equipment such as RF network analyzers can be rather costly. They are, nevertheless, useful in the design of RF networks, especially filters and other devices whose RF performance must be correctly appraised.

While a spectrum analyzer analyzes an applied signal, a network analyzer creates a signal and characterizes the devices that receive it. ... It seeks a known signal/frequency of a device output and, using vector-correction, gives a more precise measurement than the spectrum analyzer