Introduction to new features of wireless real-time spectrum analyzers

Wireless devices may periodically hang during work, interfere with the work of other consumer electronics products (such as radio stations), or fail to fully perform their intended functions. These problems will make consumers' technical level and corresponding products The supplier loses confidence.

To avoid this terrible situation, it is critical to choose a high-performance spectrum analyzer that meets the needs of today's wireless product design and debugging. This spectrum analyzer must not only be able to verify the true performance of the product, but also be able to detect it. The function of a highly integrated wireless transmitter.

In the past few years, the products that users have come into contact with are becoming more and more powerful. The purpose is to integrate a variety of convenient and practical technologies in a single device such as a mobile phone, thereby enhancing the user's multifunctional experience. New high-speed data technologies, such as HSDPA/HSUPA and A version of 1xEV-DO, provide users with more powerful features such as broadcast video and high-speed E-mail. Moreover, technologies such as satellite and Earth video broadcasting, UWB and WLAN will also be integrated into mobile handheld devices.

This trend of versatile integration presents designers with two major challenges: dealing with rapidly changing bandwidth allocation requirements and isolating problems that occur in highly integrated systems. Today, most standards only require wireless transmitter testing in a fixed operating state. However, in essence, the bandwidth required for user models of high-speed data services (such as high-speed Internet access, E-mail and periodic downloads, etc.) varies in real-time as demand.

If the ratio of the peak power to the average power of the signal varies greatly, this instantaneous bandwidth change will present a greater challenge. The above problem occurs when other wireless technologies cause instantaneous battery consumption, or when signals transmitted out of band interfere with the operation of the sensitive receiver.

Suppose a user wants to make a call from a mobile phone, connect to a data download file, use UWB to send the file to a storage device, and watch the World Cup through a continuous video service. How do designers ensure that these functions are implemented? To fully test a multi-functional integrated device, designers must go beyond the limitations of technical standards to test the actual operational and performance requirements of the device.

Another challenge faced by designers is that as device integration increases, it becomes increasingly difficult to detect wireless transmitters. To simultaneously observe a signal path in the frequency, time, and digital domains, multiple test instruments may be required, so it becomes increasingly difficult to isolate hardware and software problems. The ability to correlate time events between signal events across multiple instruments and throughout the signal path has become an integral part of debugging modern wireless designs.

Regardless of the storage capacity of spectrum analyzers, oscilloscopes, and logic analyzers, their ability to store events is limited. So when we need to correlate a signal event between multiple instruments, we must isolate the signal of interest in real time as the event occurs before the memory is full. Otherwise, it is almost impossible to intercept a problem that changes over time between multiple domains.

The key to achieving this is the way the event is triggered and the ability to cross-trigger other instruments with low latency.

Triggering artifacts, capturing event data across test environments, and analyzing time-related data are all necessary to find the fundamental source of advanced wireless device problems. With the development of the past few years, spectrum analyzers have become the main tool for analyzing RF transmission characteristics. Choosing the right tools can speed up the development of wireless designers and improve development capabilities.

Base station multi-carrier amplifiers and other high-performance wireless transmitters are capable of measuring high-dynamic-range signals using the function of a swept-tuned spectrum analyzer. Recently, vector signal analyzers have been introduced to enable users to analyze the performance characteristics of transmitters for modulated signals. In some cases, these two types of analyzers can be used in combination. The user can observe a high dynamic range signal (spectral analysis) and a modulation state (vector analysis) of the signal. But unfortunately, users can't observe both signals at the same time.

The multi-carrier amplifier (MCPA) used in the early design test tools was inefficient and could not transmit burst carrier signals such as 1xEV-DO and HSDPA. This old-fashioned MCPA is being replaced by a new MCPA device that uses the latest linearization techniques such as digital pre-correction. Thanks to advanced DSP and higher data rate D/A converters, digital pre-correction linearization technology can greatly improve the efficiency of the amplifier and reduce the cost of implementation.

Swept spectrum analyzers or vector signal analyzers can verify the spectrum and modulation performance of MCPA according to technical standards, but they cannot exceed the limits of technical standards and explain the device characteristics under actual conditions. The practical operation of modern wireless devices requires high speed data channels to have characteristics for the intended user usage pattern.

The architecture of swept-tuned spectrum analyzers and vector signal analyzers limits their ability to detect transient events. The probability of capturing a spectral event depends on the speed of the scan, the range of quantization, and the subsequent processing of the trace information (trace informaTIon). Sweep-tuned analyzers do not have vector memory and typically only record minimum, maximum, and average power consumption. Although the vector signal analyzer has a vector trace memory, it can capture signal processing at a slower rate and cannot perform continuous signal analysis tasks.